80 KiB

Raw Blame History

Framing — `apply_resource_op` delete destroys unsaved work

Revision 4. Status: PROPOSED — needs explicit user approval before implementation. DO NOT implement, DO NOT merge. Lane: resource-op-delete-guard, worktree ../pmacs-resource-op-delete, based on githubsucks/main @ 7586905.

Every count in this document was produced by a command run at revision 4, with its output pasted at the point of use. That is a reaction to this lane's own record: it shipped a stale line count, then a stale commit count, then a stale ledger citation, in three consecutive revisions — each by carrying a measurement across a base change.

This is a live data-loss bug, reproduced four ways against ad41cf1 (§1.1). A language server can destroy a buffer's unsaved edits and the file that would have held them, with no prompt, no status message, and no error return.

This PR is the implementation PR. Revision 2 drops revision 1's framing-PR-then-implementation-PR plan, which conflicted with one-feature/one-branch/one-PR. The framing is revised in place; once the design is approved, the implementation lands on this same branch and in this same PR (§8).

Revision history

Revision 3 → 4, after review round 3

Round 3 accepted the core — pre-filesystem refusal, four-phase ordering, the #171 split, Q#RD10 — and raised four P1s and a P2. All accepted.

P1 — the lane state and ledger were still false. Re-measured:

$ git rev-list --left-right --count fd7ae37...7586905
13      2

#171 is two commits behind, not zero. Revision 3's "0 behind" was measured against ad41cf1 and reported in present tense after main had moved. The ledger additionally still described #186 as revision 2 on ad41cf1 and retained the superseded ab42a79 / 153-behind entry for #171. Both lane entries are now corrected in place rather than having a correction layered above stale ground truth, which is what produced a self-contradicting ledger. §1.12 carries its count as pasted command output.

P1 — the withdrawn LSP claim survived in the normative decision. Q#RD3 still called partial application "FailureHandlingKind.Abort, the strategy the spec itself assigns to any edit containing resource changes", and §1.11 called Abort the default "by omission". Both are withdrawn. Both sites now say only that verified pmacs behaviour resembles abort-style application, with the justification resting on §1.6's reproduction. This mattered more than an ordinary error because §1.15's audit had certified the document clean while the claim was still load-bearing three sections away.

P1 — acceptance 15 had no reachable payload. WorkspaceEditResponse::from_lsp_value (src/rename.rs:95) returns Self, its doc says "A null / shapeless result yields an empty response", and the binding's only ? is lua_to_json over a value that arrived through json_to_lua. No server payload can make the parse fail, so the criterion could not fail either. Decision (Q#RD11): keep the wrap, drive the test with an explicit throwing stub, and label it defensive. Q#RD7's promise is correspondingly narrowed to "always attempts a response while the response channel remains live" — send_response is itself under an ignored pcall (builtin/runtime/lsp.lua:1843).

P1 — absent-plus-ignore had no synchronous seam. pmacs.fs.stat (builtin/runtime/fs.lua:133) dispatches async; the only synchronous filesystem binding is canonicalize (src/lua_bindings/mod.rs:6743), which resolves symlinks and returns nil for a dangling one — so it disagrees with the primitive's symlink_metadata on precisely the input this query turns on. New Q#RD12 specifies a structured Rust-backed verdict (no-op / clear / conflict) evaluated with the same symlink_metadata call, with an error contract that fails toward refusal. New criteria 11a (present + ignore + modified ⇒ still refused) and 11b (dangling symlink counts as present) supply the missing opposite direction.

P2 — acceptance and file-scope bookkeeping. Criterion 14's "fails in both directions" was false: with both duplicate buffers clean, the setup cannot distinguish first-match validation from full validation. The claim is fixed, not the setup — criterion 6 already pins validation breadth, and duplicating it would add no bite; the two are now labelled by which half of Q#RD10 each covers. §8's touch table and §7's gate list are reconciled: lsp_dispatch_seams_acceptance was named in one and omitted from the other, and the parse-stub work was missing from both.

Sweep — corrections applied at one site while a dependent site kept the old claim. Whole-document pass over every claim withdrawn or revised in revisions 2 and 3, checked at each consuming site rather than only where defined. Count: 4. Two were the P1-2 sites above (Q#RD3, §1.11). Two were the stale #171 count, which had propagated into both the revision-history entry and §1.12. Claims checked and found clean at every consuming site: rev 1's buffer-first ordering; "whole-batch atomicity"; find_buffer_for_path as the lookup; primitive-only ignore_if_not_exists; the three withdrawn impossibility claims about prompting; "no *Messages*/*warnings* buffer"; "only path 1 is unattended"; mode (d) as unowned; and Q#RD9. Each of those appears only in withdrawal text or in correctly-scoped ground truth.

Revision 2 → 3, after review round 2

Round 2 confirmed everything central from round 1 as fixed and raised four P1s. All four accepted; two sweeps run.

P1-1 — the ownership boundary was stale. Revision 2 described PR #171 as "OPEN, STALE, 153 commits behind, under re-scout" and said it claimed the rename side only. Re-checked directly: #171 is at revision 7, fd7ae37, merge-base ad41cf1 — not stale. (That sentence originally read "0 commits behind"; it was measured before main moved and is corrected in the rev 3 → 4 section above.) Revision 6 had assigned both rename and delete to Stage 2a, with the opposite policy: its reconcile_delete "kills unmodified buffers and keeps modified ones alive", i.e. the file is deleted and the modified buffer orphaned, and its §11 named that orphaning as accepted residue. Two lanes, opposite answers, same event. §1.12 and Q#RD5 now carry the settled split verbatim, and #171 revision 7 has adopted it from the other side.

P1-2 — the LSP failure-handling claim was wrong. Revision 2 said the spec "assigns Abort to any edit containing resource operations" and rested B2 on it. It does not. Recovery is described by the client's advertised failureHandling; Abort is one of four strategies, and only TextOnlyTransactional degrades to abort when resource changes are present. pmacs advertises none (§1.11, established by revision 2's own sweep), so the spec assigns pmacs no strategy at all. §1.7 and B2 are rewritten to stand on verified pmacs behaviour — §1.6's reproduced partial batch — rather than on borrowed protocol authority. This was the document's second external-spec overclaim; every external claim now carries a direct quote or is marked not established (§1.15).

P1-3 — Q#RD7 had no implementable, tested reporting seam. Three gaps confirmed by reading: _parse_workspace_edit is called at builtin/runtime/lsp.lua:1835, outside the apply_workspace_edit call revision 2 proposed to wrap, and it is fallible (lua_to_json(edit)?, src/lua_bindings/mod.rs:10161), so "always answers" was false for a parse failure; append_to_errors_buffer (src/lua.rs:401) is private, so revision 2's promise to log through it was not implementable from where it was made, and a Lua preflight rejection never reaches Rust anyway; and acceptance 13 tested the response but not the promised *errors* trace. Q#RD7 is rewritten around one seam at the server-request boundary, and of the two options offered, this revision picks wrapping parse-plus-apply rather than narrowing the claim — the fix is one line up from the existing wrap and it makes "always answers" true rather than qualified.

P1-4 — clean duplicate reconciliation was unspecified. Revision 2 said validation scans every match but never said what reconciliation does afterwards. Now an explicit decision, Q#RD10, taking the user's steer: validate every match, reconcile only today's first exact-path match. Widening would enlarge the parked lifecycle defect that Q#RD5 exists to contain; the surviving clean duplicate is named as residue handed to #171, not left silent. Acceptance 14 pins it in both directions.

Sweep — external claims. Every non-repo claim re-audited (§1.15). One was a paraphrase standing in for a quote: revision 2 asserted that "in Emacs kill-buffer on a modified file-visiting buffer prompts" without establishing it. It is true, but not for the reason a reader would assume, and the precise version matters to the argument — see §1.13, which now quotes Fkill_buffer and the INTERACTIVE macro.

Sweep — cross-lane claims. Beyond P1-1: revision 2's Q#RD8 said mode (d) "needs its own lane and a census". It has one — #171's reconcile_delete composes both removal phases and adopts the trap verbatim. Q#RD8 and §6 now name the owner instead of describing the defect as unowned. Q#RD6 additionally claims the shared query explicitly, per the boundary's "whichever lands first owns the query", so the duplicate resolves in one direction. And a gap neither lane closes — pmacs.fs.remove has no dirty check of its own — is now named as explicitly out of scope with its owner (§6), because "both lanes guard deletion" otherwise reads as the primitive being guarded.

Revision 1 → 2, after review round 1

The refusal strategy was approved in principle; revision 1 as written was not. Q#RD1 (refuse unconditionally) and Q#RD5 (take prefix-awareness now) are settled yes; Q#RD9 is settled no and is withdrawn. Six blocking points, all accepted, plus three further overclaims found by the sweep the review asked for.

Q#RD2 conflated inspection with removal — rewritten. Revision 1 proposed removing the buffer before the filesystem call. That fires arbitrary Lua on_removed callbacks while the file still exists, destroying today's useful invariant that a subscriber observes the path already gone, and it accepts losing the buffer if the deletion then fails. The correct sequence separates the two: stat/no-op → enumerate and validate → mutate filesystem → reconcile. Validation needs no removal, so a failed deletion leaves the buffer intact automatically. The review is right and revision 1 was wrong. Buffer::editing_in_progress() (src/buffer.rs:747) is a public getter, so the re-entrancy condition can also be checked during validation rather than discovered during removal.
Q#RD3 overclaimed whole-batch atomicity — rewritten and downgraded. Revision 1 called the preflight "whole-batch atomicity" and said "nothing in the batch is mutated". That is false for a sequential batch: an earlier text edit can dirty a clean buffer, and an earlier rename can move a modified buffer into a later delete's subtree, after the snapshot was taken. The preflight is now described as an early conflict check — a cheap, honest first filter, not a transaction (§2.1, Q#RD3). The real robustness comes from per-op pcall and an always-sent response (Q#RD7).
The lookup cannot be EditorCore::find_buffer_for_path — accepted and independently re-verified. It normalizes but delegates to BufferRegistry::find_by_path (src/buffer_registry.rs:168), whose own doc says "First buffer bound to path" — singular, insertion order. And pmacs.buffer.from_file (src/lua_bindings/mod.rs:3112) calls create_from_bytes with no dedup check, so duplicate path-bound buffers are reachable from public Lua. A clean first match hides a modified second. Q#RD6 now requires a full scan.
Do not expand the parked lifecycle defect — accepted. Revision 1 left it ambiguous whether a recursive delete should reconcile descendants. It must not: mode (d)'s dangling-window and last-buffer defects would be promoted from exact-path to tree-wide. Q#RD5 now says explicitly that the tree is inspected but only the exact path is reconciled.
Q#RD4 must hold at both layers — accepted. Revision 1 applied the ignore_if_not_exists early return only to the primitive. The Lua preflight must not reject an absent path merely because a modified buffer still names it.
The prompt argument was overclaimed — rewritten, and this was my error. Revision 1 said prompting was "architecturally unavailable", "the only option that is possible", and that the server-initiated path "cannot produce that answer". All three are wrong. pmacs.lsp.send_response (src/lua_bindings/mod.rs:9680) takes request_id as an ordinary value, so a workspace/applyEdit can be answered on a later tick; and a callback continuation would reuse the existing minibuffer shadow (rung 4), not add a seventh rung. The honest claim is that prompting is expensive and separately scoped, and §2.2 now argues only that, on evidence (§1.8).

Three further overclaims found by the sweep (the review asked for the defect class, not just the three cited instances — all three are the same shape: revision 1 asserted an absence or a guarantee it had not established):

"There is no *Messages* buffer and no *warnings* buffer" was misleading by omission. There is a durable append-only error surface: LuaHost::append_to_errors_buffer (src/lua.rs:401) writing *errors* (ERRORS_BUFFER_NAME, src/lua.rs:32; 49 references across src/ and builtin/), already used by log_hook_error (src/lua_bindings/mod.rs:6061), log_statusline_provider_error (:6099) and log_buffer_removed_error. This improves the design: Q#RD7 now records the refusal there too, so it survives the status line being cleared and leaves a trace on the unattended path.
"Only path 1 is fully unattended" understated the problem. Revision 1 said a raise on paths 2 and 3 "propagates out of the pmacs.async coroutine" without establishing where it lands. It lands nowhere useful: step (builtin/runtime/async.lua:196) routes an uncaught coroutine error to pmacs.error, which is undefined — 11 call sites in builtin/, zero definitions — so the error(...) fallback re-raises at the spawn site. No caller reliably reports a raise, which strengthens rather than weakens point 2's requirement.
pmacs advertises no workspace.workspaceEdit capability at all. default_client_capabilities (src/lsp.rs:3242) sends "applyEdit": true but no workspaceEdit object, so no documentChanges, no resourceOperations, and no failureHandling — grep -rn failureHandling over the tree returns 0. Revision 1 discussed batch semantics without noting that pmacs declares no failure-handling strategy. Named as ground truth (§1.11); not fixed here (§6).

Revision 1

First cut. Established the bug and the four modes, the caller inventory, the Emacs prior art, and the refusal recommendation.

0. Coherence impact (COHERENCE §20)

Journey step 6, "Receive language intelligence" (§2), and by consequence step 5, "Edit immediately" — the loss is of exactly the edits step 5 grades as "genuinely excellent". §2's verdict table grades step 6 Partial; this lane does not raise that grade, it removes a way the step can destroy the user's work. Serves Priority 1 ("treat regressions as release blockers") as a correctness floor rather than a feature.
Interaction islands: none added. The recommended design adds no modal surface at all — it refuses and reports. Revision 2 correction: revision 1 additionally claimed that the rejected prompt option would have added a seventh dispatcher rung. It would not; a callback continuation reuses the existing minibuffer shadow (rung 4). The count stays at six either way, and §6's island budget is not an argument against prompting (§2.2).
Config registry: not adopted. No knob is proposed; the refusal is unconditional (Q#RD1). An lsp.confirm-server-edits-style setting is the natural future adopter and is parked in §6.
Background-work attribution: unchanged.
No audited claim in COHERENCE.md changes, so under §25 no COHERENCE edit rides this PR. The docs/active-work.md lane for this PR does ride it, per that file's "When a PR is opened, give it a lane."

1. Ground truth (scouted and verified @ `ad41cf1`)

1.1 The bug, reproduced

pmacs.buffer.apply_resource_op with kind = "delete" destroys a modified buffer and the file backing it. Reproduced in this worktree by throwaway acceptance tests against ad41cf1, written, run, then removed — they are the model for §5's pins, not shipped artefacts. Four modes:

(a) The reported bug.

PRE: modified=true text="UNSAVED EDIT ORIGINAL ON DISK\n"
apply_resource_op result: Ok(())
buffers before=3 after=2
file still on disk? false

The call returns Ok(()). The file is gone. The buffer is gone. The text existed in exactly one place and now exists nowhere.

(b) ignore_if_not_exists = true destroys the buffer having done no filesystem work at all. When the path is already absent, the delete arm skips the remove_file — and falls through to the buffer reconciliation anyway:

file gone; buffers=3; buffer holds the only copy
result: Ok(())
buffers after=2
CONFIRMED: ignore_if_not_exists=true did ZERO fs work yet still destroyed the only copy.

The create arm returns early (return Ok(())) under the analogous ignore_if_exists condition; the delete arm's Err(NotFound) branch does not return.

(c) recursive = true fails in the opposite direction.

recursive delete result: Ok(())
inner file exists? false
buffers before=3 after=3
inner buffer still in registry? true

The tree goes; no buffer is reconciled, because the lookup is for the directory path and buffers hold file paths. The most destructive arm does the least reconciliation. Here the data survives — in an orphaned buffer — which is strictly safer than (a), and is why the fix must not be "make delete behave like the recursive case".

(d) Removal is not kill_buffer.

victim is the active buffer? true
window.buffer():is_valid() after delete => Ok(Boolean(false))
editor.file_path() after delete => Ok(Nil)

buffers now: 1
delete of the LAST buffer: Ok(())
buffers after: 0  (0 => registry driven empty)

EditorCore::kill_buffer (src/editor_core.rs:4590) refuses the last buffer and rebinds every window to a fallback. This path does neither. (d) is parked (§6, Q#RD8) and, per Q#RD5, must not be widened by this lane.

1.2 There is no dirty check at any link in the chain

The delete arm (src/lua_bindings/mod.rs:3313) — stats, deletes, then find_by_path, then remove_buffer_and_fire. No is_modified.
remove_buffer_and_fire (:1592) — registry.remove(id) then after_buffer_removed (:1602), which clears keymaps, config, folds and fires on_removed. No dirty check.
BufferRegistry::remove (src/buffer_registry.rs:127) — one guard, and not this one:
```
if let Some(buf) = self.buffers.get(&id)
    && buf.editing_in_progress()
{
    return Err(RegistryError::ConcurrentEdit { ... });
}
```
That refuses re-entrant removal from inside an edit intercept (T M7.4). It says nothing about unsaved content.

The report's description is accurate at every link. Modes (b), (c) and (d) are additional.

1.3 The ordering is disk-first, so no guard placed later can help

The arm performs the irreversible filesystem operation before it has looked for a buffer. A fix that adds a dirty check to the existing buffer-reconcile block is not a fix — it converts mode (a) into mode (c), and the user's file is still gone. The check must happen in a phase that precedes the filesystem call, which is what Q#RD2 introduces.

1.4 `is_modified` is available, singular, and the lookup around it is not

One field, Buffer::is_modified: bool (src/buffer.rs:164); one accessor (:473); one public mutator mark_clean (:488). Buffer::editing_in_progress() (:747) is likewise a public getter, so both conditions Q#RD2 needs are inspectable without mutating.
Zero features refuse or confirm on unsaved state today. kill_buffer, editor.quit (whose editor.before-quit veto hook has no subscriber) and dired.revert all ignore it; the only behavioural consumer is autosave's gather filter (src/autosave.rs:363), which includes rather than refuses. This lane introduces the first refusal keyed on unsaved state and should be read as setting that precedent.
The registry lookup is singular and duplicates are reachable. BufferRegistry::find_by_path (src/buffer_registry.rs:168) returns the first match in insertion order — its own doc says "First buffer bound to path". EditorCore::find_buffer_for_path (src/editor_core.rs:935) normalizes and then delegates to it, so it inherits the singularity. And duplicates are creatable from public Lua: pmacs.buffer.find_or_open (src/lua_bindings/mod.rs:3162) dedups via find_by_path, but pmacs.buffer.from_file (:3112) does not — it calls create_from_bytes unconditionally and then set_buffer_path. Two from_file calls on one path yield two path-bound buffers, and a clean first match hides a modified second. This is why Q#RD6 requires a full scan rather than the existing wrapper.
Lua reaches modified state as buf:is_modified() (:1261) and pmacs.describe.buffer(id).modified (:6359). It is not a key on the pmacs.buffer module table, so the preflight needs a new query (Q#RD3).

1.5 Who calls this, and what happens to a raised error

One production caller: apply_workspace_edit (builtin/runtime/lsp.lua:1301), at :1346. Three callers of that:

#	Call site	Origin	Disposition of a raise
1	`handle_server_requests` (`lsp.lua:1815`), call at `:1836`	server-initiated `workspace/applyEdit`	Swallowed. The pump runs under `pcall(handle_server_requests)` (`:1892`); the raise unwinds past the `pcall(pmacs.lsp.send_response, ...)` that answers the request, so the user sees nothing and the server is never answered.
2	LSP rename (`lsp.lua:2311`)	user, `M-x`	Raises out of the `pmacs.async` coroutine — see below.
3	code action apply (`lsp.lua:2373`)	user, `M-x`	as #2.

Revision 2 correction. Revision 1 called only path 1 unattended. Paths 2 and 3 are no better: step (builtin/runtime/async.lua:196) handles an uncaught coroutine error by calling pmacs.error if it exists and error(...) otherwise —

if not ok then
  if pmacs.error then
    pmacs.error("pmacs.async: coroutine raised: " .. tostring(yielded))
  else
    error("pmacs.async: coroutine raised: " .. tostring(yielded))
  end
  return
end

— and pmacs.error is undefined: 11 call sites across builtin/, zero definitions. So the fallback always runs and re-raises at the spawn site. No caller reliably surfaces a raise to the user. Hence Q#RD7: the refusal travels as a value, never as an exception alone.

src/rename.rs:25 documents the division of labour — rename.rs parses and never mutates; Lua drives the primitives "so the application strategy stays configurable". That strategy is what this framing picks.

1.6 A partial batch is already possible today — verified

The applier's loop (lsp.lua:1340-1349) calls the primitive unprotected. Two delete ops where the second raises:

batch result: Err(... "apply_resource_op delete: No such file or directory (os error 2)")
a.txt still exists? false (false ⇒ partial batch)

The first op stayed applied. Partial application on I/O error is the status quo, not something a refusal introduces. Data loss is strictly worse than a failure class the code already tolerates.

It also shows the preflight's contract is narrower than its comment implies. lsp.lua:1287-1291 says the applier "refuses to mutate anything unless every URI it touches resolves to a real file path first". True — but URI resolution is the only precondition; the plan loop (:1302-1336) validates nothing about the filesystem or the registry. That loop is where Q#RD3's conflict check goes.

1.7 The batch is sequential; the protocol assigns pmacs no failure strategy

Claims about the LSP specification (3.18), each a direct quote, not a paraphrase — and note carefully what they do not say.

Sequential execution — this is the load-bearing one, and it is unconditional:

"If resource operations are present, clients need to execute the operations in the order in which they are provided."

Failure recovery is the client's declared choice, not a fixed rule:

"How the client recovers from the failure is described by the client capability: workspace.workspaceEdit.failureHandling"

FailureHandlingKind has four values, quoted from the spec's own namespace block:

Value	Doc comment (verbatim)
`Abort`	"Applying the workspace change is simply aborted if one of the changes provided fails. All operations executed before the failing operation stay executed."
`Transactional`	"All operations are executed transactionally. That means they either all succeed or no changes at all are applied to the workspace."
`TextOnlyTransactional`	"If the workspace edit contains only textual file changes they are executed transactionally. If resource changes (create, rename or delete file) are part of the change the failure handling strategy is abort."
`Undo`	"The client tries to undo the operations already executed. But there is no guarantee that this is succeeding."

Revision 3 correction. Revision 2 read this as "the protocol assigns Abort to any edit containing resource operations". That is wrong. Abort is one of four strategies a client may advertise; Transactional covers all operations and Undo attempts rollback. Only TextOnlyTransactional degrades to abort in the presence of resource changes, and that degradation is a property of that strategy, not of resource operations in general.

And pmacs advertises none of them (§1.11). So the specification does not tell us what pmacs should do here; it tells us the question is the client's to answer. Revision 2 borrowed authority it did not have.

What survives, and is sufficient: sequential execution is unconditional, which is why a snapshot preflight is necessarily incomplete — an earlier op can change the facts a later op's precondition was evaluated against. That, plus §1.6's verified pmacs behaviour (a partial batch already happens today on I/O error), is the whole basis for Q#RD3 and B2. The justification is that partial application is already what pmacs does and is safer than data loss — not that the protocol blesses it.

1.8 What prompting would actually cost — corrected

Revision 1 called prompting impossible. It is not. Establishing what is and is not true:

True, and verified:

The primitive cannot suspend. apply_resource_op is a synchronous Rust closure performing its std::fs calls inline; there is no yield point. A prompt therefore cannot be issued from inside it — the applier would have to be restructured into a continuation chain.
pmacs.minibuffer.read (src/lua_bindings/mod.rs:13380) is asynchronous-by-callback, and Minibuffer::accept (src/minibuffer.rs:334) deliberately returns the callback rather than invoking it, because "firing user code from inside the minibuffer would re-enter the registry" (:332).
The minibuffer is a single slot that replaces without asking. Minibuffer::session: Option<MinibufferSession> (src/minibuffer.rs:71), and begin (:106) is documented "Replaces any existing session". A prompt raised mid-batch while the user has a minibuffer open silently destroys the in-flight prompt and its callbacks.
There is no y_or_n helper in the tree — a named deferral (docs/dired-framing.md:854).

False, as revision 1 had it:

"The server-initiated path cannot produce that answer." It can. pmacs.lsp.send_response (src/lua_bindings/mod.rs:9680) takes (server_id, request_id, result, err) as ordinary values; nothing binds it to the pump's call frame, and request_id arrives on the event as a plain Lua value that can be stashed. A workspace/applyEdit can be answered on a later tick.
"It costs a seventh dispatcher shadow." It does not. The minibuffer is already rung 4; a continuation reuses it.

So the honest case against prompting (§2.2) is scope, not possibility: queuing, cancellation, collision with an already-active single-slot minibuffer, and revalidation of every precondition after the user turn — because the world moves during the turn, which is §1.7's problem again, only worse.

1.9 Autosave cannot serve as a pre-delete backup

Verified against src/autosave.rs: there is no per-buffer write entry point (the only public writer is sweep, :261, which walks the whole registry); sweep skips clean buffers (:363); removing a buffer purges its recovery file — the on_removed callback registered at builtin/runtime/autosave.lua:167 calls discard_buffer (:511), with a sweep-time GC backstop (:290-306), pinned by tests/autosave_acceptance.rs:702; and deleting the file flips the recovery to Stale, which is never auto-offered.

1.10 Report channels — corrected

pmacs.editor.set_status (src/lua_bindings/mod.rs:13036) is transient; it is cleared at the top of every dispatch_key.
Revision 2 correction: a durable surface exists. LuaHost::append_to_errors_buffer (src/lua.rs:401) appends to *errors* (ERRORS_BUFFER_NAME, src/lua.rs:32), creating it on first use, and is the established idiom for "a callback failed and the user was not watching" — log_hook_error (src/lua_bindings/mod.rs:6061), log_statusline_provider_error (:6099), log_buffer_removed_error, and the config error path (src/lua_bindings/config.rs:511). Revision 1 claimed no such channel existed. It does, it is Rust-side, and Q#RD7 now uses it.

1.11 pmacs advertises no `workspace.workspaceEdit` capability

default_client_capabilities (src/lsp.rs:3242) sends "applyEdit": true (:3259) inside its "workspace" block (:3253) but no workspaceEdit object at all. So pmacs declares neither documentChanges ("The client supports versioned document changes in WorkspaceEdits"), nor resourceOperations ("The resource operations the client supports"), nor failureHandling ("The failure handling strategy of a client if applying the workspace edit fails") — grep -rn "failureHandling" over the tree returns 0.

Two consequences worth stating plainly. pmacs applies resource operations it never declared support for; and it declares no failure strategy at all — which is not the same as defaulting to one. The spec establishes no default for a client that advertises nothing, so pmacs's actual behaviour is simply whatever its code does, which §1.6 verified resembles abort-style application without being licensed as it. (Revision 3 wrote "Abort semantics are the de facto behaviour by omission"; that smuggled the withdrawn claim back as a default and is itself withdrawn at revision 4.) Neither is fixed by this lane — declaring capabilities changes what servers send, which is a behavioural change needing its own evidence (§6). It is recorded because a framing about batch failure semantics that did not notice pmacs declares none would be describing half the system.

1.12 The rename arm is more careful, and differently careful

"rename" (src/lua_bindings/mod.rs:3291) does std::fs::rename, then find_by_path, then set_buffer_path — it rebinds, preserving contents and modified state. Delete destroys. Rename treats the buffer as the valuable thing and the path as a mutable attribute; delete treats the buffer as a cache of the file.

Both arms share the §1.4 lookup defects.

Cross-lane state, re-measured at revision 4. PR #171 (dired Stage 2) is at revision 7, fd7ae37, merge-base ad41cf1:

$ git rev-list --left-right --count fd7ae37...7586905
13      2

Thirteen ahead, two behind — and those two are exactly PR #189's COHERENCE change, so no cross-lane conclusion turns on them. Revision 3 of this document said "0 commits behind"; that was measured against ad41cf1 and reported after main had moved to 7586905, which is the third instance in this lane of quoting a census as a constant. Revision 2 of this document described it as "OPEN, STALE, 153 commits behind, under re-scout" and said it claimed the rename side only; both halves of that were out of date. Its revision 6 assigned rename and delete reconciliation to Stage 2a with the opposite policy — reconcile_delete killing unmodified buffers and keeping modified ones alive, so the file is deleted and the modified buffer orphaned, with that orphaning named as accepted residue.

The settled split (identical wording carried by both lanes):

#186 owns the urgent pre-filesystem refusal for synchronous apply_resource_op. #171 later owns full post-delete lifecycle reconciliation, including the async race where a buffer becomes modified after dired dispatch. #171's revision 7 adopts the refusal and stops saying LSP intentionally deletes modified files.

#171 revision 7 has adopted this from its side: its Q#DR18 takes this document's Q#RD1 refusal rather than re-deciding it, and it records the reason the refusal cannot simply be extended to cover dired — dired never calls apply_resource_op. It calls pmacs.fs.remove, which dispatches a worker, so a synchronous refusal inside the primitive cannot reach it at any strength. That asynchronous window is #171's, and naming it here is what keeps this lane from appearing to close a defect it does not close.

The older in-tree note at docs/dired-framing.md:807-819 (Stage 1-era) still describes the rename-side lookup defect accurately, but it is superseded as a statement of plan by #171's Stage 2 document, which exists only on that branch.

1.13 Prior art — claims about Emacs, not pmacs

Verified against lisp/progmodes/eglot.el, emacs-mirror/emacs master.

Eglot orders the operations the other way round. Its do-delete:

(do-delete (path &key recursive ignoreIfNotExists &allow-other-keys)
  (let ((exists (file-exists-p path)))
    (when (and (not exists) (not ignoreIfNotExists))
      (eglot--error "File %s does not exist" path))
    (when exists
      ;; Kill buffer if the file is visited
      (let ((buf (find-buffer-visiting path)))
        (when buf (kill-buffer buf)))
      (delete-file path recursive))))

The buffer is killed before the file is deleted. Note also that the exists guard means ignoreIfNotExists does not fall through to the buffer kill — the asymmetry mode (b) exposes in pmacs.

Revision 3 precision. Revision 2 asserted that "in Emacs kill-buffer on a modified file-visiting buffer prompts", which was a paraphrase carrying real weight in the argument. It is true, but the mechanism is not the obvious one and the difference matters. From Fkill_buffer (src/buffer.c):

    /* Is this a modified buffer that's visiting a file? */
    modified = !NILP (BVAR (b, filename))
      && BUF_MODIFF (b) > BUF_SAVE_MODIFF (b);

    /* Query if the buffer is still modified.  */
    if (INTERACTIVE && modified)
      {
	/* Ask whether to kill the buffer, and exit if the user says
	   "no".  */
	if (NILP (calln (Qkill_buffer__possibly_save, buffer)))
	  return unbind_to (count, Qnil);

and INTERACTIVE is (src/commands.h):

/* Nonzero if input is coming from the keyboard.  */

#define INTERACTIVE (NILP (Vexecuting_kbd_macro) && !noninteractive)

So the gate is "Emacs has a keyboard", not "this function was reached through call-interactively". Eglot's do-delete calls kill-buffer programmatically from Lisp and still prompts in a normal session — but does not in batch mode or while a keyboard macro is executing. Revision 2's sentence was right for a reason it never established, and false in two environments it never considered.

Two riders, both verified: eglot ignores kill-buffer's return value, so declining the kill still deletes the file — the buffer and its text survive, which is milder than pmacs's failure but is not a refusal. And the prompt is not buffer-offer-save, whose own docstring says so: "Note that this option has no effect on kill-buffer'; if you want to control what happens when a buffer is killed, use kill-buffer-query-functions'."

Ordering note (rev 2, sharpened at rev 3): Emacs's ordering is not what Q#RD2 adopts. Emacs can afford buffer-first because kill-buffer is itself the consent gate — conditionally, per the INTERACTIVE gate above. pmacs has no such gate at all, so it validates first and reconciles last (Q#RD2), which yields the same safety unconditionally and without firing callbacks against a file that still exists.

Eglot confirms server-initiated edits by default, as a whole-batch decision taken before anything is applied. eglot-confirm-server-edits defaults to '((t . maybe-summary)); prepare builds closures touching nothing, then the decision, then apply-all. The maybe-* decisions skip the prompt only when the batch is peaceful:

(peaceful
 (and
  all-text-edits
  (cl-loop for op in prepared
           always (find-buffer-visiting (cadddr op)))))

all-text-edits is a conjunction over the whole batch, so a batch containing any create/rename/delete always prompts under the default.

1.14 `apply_resource_op` has no direct test coverage

grep -rn "apply_resource_op" tests/ src/ returns 4 lines: one doc comment in src/rename.rs and three inside the binding's own definition. Zero tests name it.

One indirect acceptance exercises it: m4_15_workspace_edit_resource_ops_apply_in_order (tests/m4_acceptance.rs:4014), driven by the resourceops mode of the fake server (src/bin/pmacs_fake_lsp.rs:834). Its deleted c.rs is never opened, so the entire buffer-reconciliation half is untested. That suite and that fake are where §5's pins belong.

1.15 External-claim audit (revision 3)

Two external-spec overclaims in two revisions is a pattern, not an accident, so every claim in this document that is not about this repository is listed here with its evidence. The standing rule: an external claim carries a direct quote or it is marked not established.

This audit itself failed at revision 3, and the failure mode is recorded because the table is now something readers trust. Revision 3 marked the Abort claim WITHDRAWN in row 4 while Q#RD3 — the normative decision — still asserted it, and §1.11 still called it a default. The audit checked each claim where it was defined, not at every site that consumed it, so it certified a document that was internally contradictory. A withdrawal recorded in an audit while the claim stays load-bearing elsewhere is worse than no withdrawal, because the audit converts an error into a false assurance.

So the audit procedure is, from revision 4: for each row, grep the whole document for the claim's terms and check every hit, not the defining section. Revision 4 ran that and found two surviving consumers (§1.15 is the audit; the fix is in Q#RD3 and §1.11).

#	Claim	Source	Status
1	Resource ops execute in provided order	LSP 3.18 `WorkspaceEdit`	Quoted, §1.7. Unconditional.
2	Recovery is described by the client's `failureHandling`	LSP 3.18	Quoted, §1.7.
3	The four `FailureHandlingKind` doc comments	LSP 3.18	Quoted verbatim, §1.7 table.
4	~~The spec assigns `Abort` to resource-op edits~~	—	WITHDRAWN (P1-2). Never supported; it conflated one client-selectable strategy with a protocol rule.
5	`documentChanges` / `resourceOperations` / `failureHandling` capability doc comments	LSP 3.18	Quoted, §1.11.
6	eglot's `do-delete` body	`lisp/progmodes/eglot.el`, emacs-mirror master	Quoted from source, §1.13.
7	`eglot-confirm-server-edits` default and the `peaceful` conjunction	same	Quoted from source, §1.13.
8	Emacs prompts when killing a modified file-visiting buffer	`src/buffer.c` + `src/commands.h`	Quoted at rev 3, §1.13. Was a bare paraphrase at rev 2; the real gate is `INTERACTIVE`, i.e. keyboard present — not `call-interactively` — so it does not hold in batch or during a keyboard macro.
9	`buffer-offer-save` does not affect `kill-buffer`	`lisp/files.el` docstring	Quoted, §1.13.

Not established, and therefore not claimed anywhere in this document: what lsp-mode (as distinct from eglot) does with DeleteFile; and the exact ApplyWorkspaceEditResult field list beyond applied and failureReason, which this document uses only because pmacs's own code already sends them (builtin/runtime/lsp.lua:1841).

2. The decision space

2.1 Recommended — validate before mutating, at the primitive; conflict-check early, in the applier

The primitive refuses before touching disk. The applier catches what it can early, and reports honestly what it cannot.

Layer 1 — the primitive (the invariant). The delete arm becomes four ordered phases:

stat / no-op decision  →  enumerate and validate affected buffers
                       →  mutate the filesystem
                       →  reconcile the registry

Validation inspects; it does not remove. If any affected buffer is modified — or is mid-edit (editing_in_progress) — the op returns an error having touched nothing. Because validation removes nothing, a filesystem failure leaves every buffer intact automatically, and on_removed still fires only in the reconcile phase, i.e. with the path already gone, preserving today's invariant.

Layer 2 — the applier (early conflict check + robust reporting). apply_workspace_edit's existing plan loop gains a modified-buffer conflict check for delete ops and returns its existing nil, message. This is a filter, not a transaction (§1.7): it catches the common case cheaply, before anything is mutated, and it is honest that a sequential batch can still refuse mid-flight. What makes mid-flight refusal survivable is Q#RD7: each primitive call is wrapped, every failure becomes nil, message, the origin buffer is restored best-effort, and the unattended caller always answers the server.

Neither layer is redundant. Layer 1 alone leaves every batch failure reported through a channel that does not work (§1.5). Layer 2 alone leaves the primitive armed for direct callers — pmacs.buffer.apply_resource_op is public Lua API, and dired Stage 2's own plan names delete reconciliation as its 2a substrate.

Why this beats the runners-up, in one sentence each: it is the only option that puts the check strictly before the irreversible step without either firing callbacks into a half-changed world (buffer-first) or inventing a recovery surface (backup), and it is the only one whose cost is bounded by this lane.

2.2 Prompt the user — rejected on scope, not on possibility

Revision 2 rewrite. Revision 1 argued impossibility on three grounds; two were wrong (§1.8) and are withdrawn. The surviving argument is narrower and is about cost:

The applier must become a continuation chain. The primitive cannot suspend (§1.8), so the remaining plan has to be carried as a closure across the user turn — with cancellation, and with revalidation of every precondition afterwards, because the world moves during the turn. That is §1.7's sequential-batch problem with a human-scale delay inserted into it.
The minibuffer is a single slot that replaces without asking (Minibuffer::begin, "Replaces any existing session"). A prompt raised while the user is mid-M-x destroys their in-flight prompt. Queuing is therefore a prerequisite, and no queue exists.
Deferred answers need a pending-request ledger. Answering workspace/applyEdit later is possible (§1.8) but means retaining (server_id, request_id) across ticks and deciding what happens if the server dies first. purge_dead_pending exists for client requests; there is no equivalent for held server requests.

None of that is impossible; all of it is a separate lane with its own framing. Refusing is the correct move for a live data-loss bug, and a prompt can later loosen an unconditional refusal without either change invalidating the other.

2.3 Save first, then delete — rejected

Silently converts an unsaved edit into a committed one and then destroys it — more destructive, not less, because it overwrites the on-disk original immediately before removing the file. It also cannot be relied on: save_inner (src/editor_core.rs:1908) refuses at :1917 when the file changed on disk since it was read, so the fallback question is unanswered and we are back to refusing.

2.4 Back up the contents somewhere recoverable — rejected

Rejected on evidence (§1.9): the decisive fact is that removing the buffer deletes the recovery file, so the backup is destroyed by the operation it exists to survive. Building a side-store outside autosave/ means a second recovery surface with its own discovery, GC and lifecycle, to make a destructive operation feel safe.

2.5 Key the behaviour on LSP-versus-user provenance — rejected

apply_resource_op takes no provenance argument and there is no ambient caller identity. Adding one makes the primitive's safety depend on a caller-supplied flag — any caller that omits it is unguarded, which is the failure mode the lane exists to remove. COHERENCE §10 (extension trust classes) is unbuilt, so there is no trust dimension to key on. The refusal is unconditional and provenance-blind.

3. Decisions

Q#RD1 — Refuse. Do not prompt, do not save, do not back up — SETTLED YES

A delete whose target set contains a modified buffer fails, changing nothing on disk and nothing in the registry. This is the first refusal in the codebase keyed on unsaved state (§1.4) and is intended as the precedent for kill_buffer and editor.quit, which have the same gap.

Q#RD2 — Validate before mutating; reconcile last — REWRITTEN at rev 2

Four phases, in order: stat/no-op decision → enumerate and validate affected buffers → mutate the filesystem → reconcile the registry.

Validation inspects only. It checks Buffer::is_modified() and Buffer::editing_in_progress() (src/buffer.rs:473, :747) across the affected set. Nothing is removed, so nothing can be lost if a later phase fails.
editing_in_progress moves from discovery to validation. Today a ConcurrentEdit refusal from BufferRegistry::remove arrives after the file is gone. Checking it during validation means a delete invoked from inside the target's own edit intercept refuses before disk.
on_removed still observes the path already gone. Reconciliation is the last phase, so the invariant revision 1 would have broken is preserved. This is the specific defect revision 1's buffer-first ordering introduced, and it is why that ordering is withdrawn.
A filesystem failure leaves buffers untouched, automatically rather than by compensation.

Q#RD3 — The preflight is an early conflict check, not a transaction — DOWNGRADED at rev 2

apply_workspace_edit's plan loop gains a modified-buffer conflict check for delete ops and returns its existing nil, message. It is described in the code comment and here as a filter:

What it guarantees: when the conflict is visible at plan time, nothing in the batch is mutated at all, and the user gets one clear message.
What it does not guarantee, stated plainly: documentChanges are sequential (§1.7). An earlier text edit can dirty a clean buffer, and an earlier rename can move a modified buffer into a later delete's subtree, after the snapshot. Then the preflight passes and the primitive refuses mid-batch, leaving earlier operations applied. That outcome resembles abort-style application, and it is what pmacs already does today on an I/O error (§1.6, verified). It is not licensed by the specification: the spec assigns no strategy to a client that advertises none (§1.7), so the justification is observed pmacs behaviour plus the judgement that a visible partial refactor beats unrecoverable unsaved work — nothing more.
Revision 1 called this "whole-batch atomicity" and said "nothing in the batch is mutated". That was false and is withdrawn.

The check needs a path-keyed modified query that Lua lacks (§1.4). It must be one query shared with the primitive's validation phase, so the two cannot drift apart.

Q#RD4 — `ignore_if_not_exists` short-circuits at both layers — WIDENED at rev 2

When the path is absent and ignore_if_not_exists is set, the op is a no-op:

Primitive: return early without touching the registry — the create arm's existing idiom and Eglot's exists guard (§1.13).
Preflight: must not reject the batch merely because a modified buffer still names that absent path. Revision 1 applied this only to the primitive, which would have made the preflight refuse an op the primitive treats as a no-op — a refusal with no underlying destruction, i.e. a false positive that blocks legitimate edits.

Mode (b) is not a special case of the main bug; it is a missing early return, and a fix aimed only at the "we actually deleted something" branch leaves it live.

Q#RD5 — Recursive deletes are inspected tree-wide but reconciled exact-path — SETTLED YES, NARROWED at rev 2

Mode (c) proves recursive = true reconciles nothing, so an exact-path guard is bypassed by the most destructive arm. Therefore:

Validation is prefix-aware: every buffer whose path lies beneath the deleted directory is inspected, and any modified one refuses the op. Without this the guard has a trivial reachable bypass.
Reconciliation is not widened: after a successful clean recursive delete, descendant buffers are left exactly as today — orphaned and clean. Removing them now would promote mode (d)'s dangling-window and last-buffer defects from an exact-path defect to a tree-wide one, which is precisely the parked lifecycle work this lane must not expand into (Q#RD8).

The asymmetry is deliberate and is the point: inspect widely, mutate narrowly.

Boundary with dired — restated at rev 3. The settled split (§1.12, quoted there verbatim and carried identically by #171) is:

#186 owns the urgent pre-filesystem refusal for synchronous apply_resource_op. #171 later owns full post-delete lifecycle reconciliation, including the async race where a buffer becomes modified after dired dispatch.

The stale justification is withdrawn. Revision 2 supported taking the delete side now by citing the ledger's "OPEN, STALE, 153 commits behind, under re-scout" assessment of #171. That re-scout has finished; #171 is at revision 7, integrated to ad41cf1. The conclusion is unchanged and rests on urgency alone — this is a live data-loss bug with a reproduction, and a refusal that must precede the filesystem call cannot be deferred to a lane that acts after it. It no longer rests on any claim about #171's freshness, and it must not be re-argued from one.

Q#RD6 — The shared query scans all path-bound buffers — REWRITTEN at rev 2

Revision 1 said the guard would use EditorCore::find_buffer_for_path. That is wrong and is withdrawn: it normalizes but delegates to the singular, first-match-only find_by_path (§1.4), and duplicate path-bound buffers are reachable from public Lua via pmacs.buffer.from_file. A clean first match would hide a modified second — a silent guard bypass.

The shared query therefore:

scans every path-bound buffer, returning all matches rather than the first;
normalizes once and compares normalized forms, so a raw-path lookup cannot miss a stored normalized path;
matches with component-aware Path::starts_with, not string prefix — so /tree does not match /tree-sibling;
is the single query used by both the primitive's validation phase and the Lua preflight (Q#RD3).

This lane claims the query. The boundary's rule is "whichever lands first owns the query and the other adopts it", and #171 revision 7 records that this rule's four clauses are character-for-character what it had written independently for reconcile_delete. To stop both lanes asserting ownership: #186 owns and implements the shared walk, #171 adopts it and extends it to reconcile_rename. If #171 lands first the claim inverts and this decision is what gets deleted — but it is stated in one direction so the duplicate resolves rather than persisting.

"Modified" is Buffer::is_modified(). No new notion of dirtiness.

Explicitly not guarded: a clean buffer. A delete whose target is open but unmodified proceeds and removes the buffer, as today. Overreach would break m4_15 and would fail legitimate deletes for users who merely have the file open.

Q#RD7 — One reporting seam at the server-request boundary — REWRITTEN at rev 3

§1.5 established that no caller reliably surfaces a raise. Revision 2 answered that with three promises that did not compose into anything implementable; revision 3 replaces them with one seam.

Where the seam is: the server-request boundary, i.e. the workspace/applyEdit arm of handle_server_requests (builtin/runtime/lsp.lua:1833-1843). Everything below hangs off that single point.

Wrap parse and apply, not apply alone. Revision 2 wrapped "every primitive call inside apply_workspace_edit", which does not cover pmacs.lsp._parse_workspace_edit — it is called at lsp.lua:1835, one line above apply_workspace_edit, and it is fallible (lua_to_json(edit)?, src/lua_bindings/mod.rs:10161). A parse failure therefore escaped, was swallowed by pcall(handle_server_requests), and left the server unanswered — the exact defect being fixed, one line out of scope.

Of the two options offered in review, this revision picks wrapping parse-plus-apply rather than narrowing the wrap to applier execution failures. Reason: the wrap moves up exactly one line and costs nothing, so the boundary is uniform regardless of which call fails.

Revision 4 correction to the strength of the claim. Revision 3 said this made "always answers" true without qualification. It does not, for two independent reasons, and the honest wording is "always attempts a response while the response channel remains live":
- send_response is itself called under an ignored pcall (builtin/runtime/lsp.lua:1843), so its failure is unobservable to the applier. A dead or wedged transport cannot be answered by any amount of wrapping upstream.
- The parse call is, on the evidence, not reachably fallible — see acceptance 15 and Q#RD11.
Every failure becomes a value. Refusal, I/O error, and parse failure all converge on the existing nil, message shape, which all three callers already handle. No exception escapes the applier.
The unattended caller always attempts a response: { applied = false, failureReason = ... } is constructed and sent in every failure case the applier can observe. Whether it lands is the transport's business, and the applier cannot tell (see above).
The durable trace is written at this boundary, not in the primitive. Revision 2 promised logging through LuaHost::append_to_errors_buffer (src/lua.rs:401). Two problems, both confirmed: it is private, so it is not callable from where the promise was made; and a Lua preflight rejection never reaches the Rust primitive at all, so primitive-side logging would miss the common unattended case entirely. So: a narrow Lua-callable surface that appends one attributed record to *errors*, invoked at the server-request boundary after any applied = false, with the label lsp:workspace/applyEdit. One call site, one label, reachable from the layer that actually knows the outcome.
The origin buffer is restored best-effort on the failure path too. Today pcall(pmacs.buffer.find_or_open, origin) runs only after a successful loop; an early failure return would strand the user in whatever buffer the last op left active.
The message names the buffer and says what to do. Not a bare errno.

Acceptance 13 tests both halves of the boundary — the response the server receives and the *errors* record — because revision 2 tested only the first while promising the second.

Q#RD8 — The window/last-buffer defects do not land here

Mode (d) is real and parked (§6). It is a different failure from data loss, and it is shared with pmacs.buffer.remove.

The trap that makes the obvious fix wrong: the two removal paths clean disjoint sets. kill_buffer handles the last-buffer refusal, round_trip_buffers, side-window collapse and window rebinding, but not keymaps, config, folds or on_removed callbacks; remove_buffer_and_fire handles exactly the latter and none of the former. Neither is a superset, so "just call kill_buffer instead" would silently regress four cleanups.

Revision 3 — that lane now exists. Revision 2 said mode (d) "needs its own lane and a census", which was true when written and is not now. #171's reconcile_delete composes both phases for every id it kills and reroutes apply_resource_op's delete arm through it, and #171 revision 7 records the disjoint-set trap independently. So mode (d) is owned, not unowned, and per Q#RD5 this lane's job is narrower than it looked: not merely "don't fix it here" but don't enlarge the surface #171 has to fix.

Q#RD9 — WITHDRAWN at rev 2

Revision 1 proposed that, after a buffer-first removal, a filesystem failure would leave the buffer unrestored. Q#RD2's phase ordering makes the situation unreachable: nothing is removed before the filesystem mutation succeeds, so there is no lost buffer to restore. The decision number is retained rather than reused, so review can see it went away rather than being renumbered.

Q#RD10 — Validate every match; reconcile today's first match only — NEW at rev 3

Q#RD6 makes validation scan all path-bound buffers. Revision 2 never said what reconciliation does afterwards when several match, which left the common duplicate case undefined. It is now decided:

Validation: every match. If any buffer bound to the path — or beneath it, for a recursive delete — is modified, the op refuses. A clean first match must not be able to hide a modified second (§1.4).
Reconciliation: exactly today's behaviour. After a successful delete, the single first exact-path match is removed, as find_by_path does now. Additional clean duplicates are left in place.

Why not remove them all. Every extra removal goes through remove_buffer_and_fire, which is phase 2 without phase 1 (Q#RD8) — so removing N duplicates creates up to N dangling windows and brings the registry N steps closer to empty. That is precisely the parked defect Q#RD5 is written to contain, and widening it here would hand #171 a larger problem in exchange for tidiness this lane does not need.

The honest cost, stated rather than buried: a surviving clean duplicate is left bound to a path that no longer exists — the same orphan shape as mode (c), on a narrower trigger. It is residue handed to #171, whose lifecycle transaction can then remove all matches safely because it composes both phases. This lane's contract is that no unsaved work is lost, not that the registry ends tidy.

Acceptance 14 pins both directions, so neither widening nor narrowing can happen silently.

Q#RD11 — The parse wrap is a defensive boundary, tested with a stub — NEW at rev 4

Revision 3 justified wrapping _parse_workspace_edit by asserting it was reachably fallible. On the evidence it is not, and acceptance 15 as written could not fail:

WorkspaceEditResponse::from_lsp_value (src/rename.rs:95) returns Self, not a Result. Its own doc comment says "A null / shapeless result yields an empty response."
The binding's only ? is lua_to_json(edit)? (src/lua_bindings/mod.rs:10161), and its input arrived as JSON through json_to_lua. Every value that round-trip produces is accepted going back.

So no fake server can send a payload that makes the parse fail. Decision — the first of the two options offered: keep the wrap, and label it a defensive boundary test driven by an explicit throwing test stub for pmacs.lsp._parse_workspace_edit. Reasons: the wrap costs one line and makes the boundary uniform, so a future parse that does become fallible is covered by construction rather than by remembering; and the promise in Q#RD7 is narrowed to match reality rather than propped up by an unfalsifiable criterion.

What this explicitly is not: a claim that a server can trigger it. Acceptance 15 is labelled defensive, and it substitutes the stub rather than dressing up a reachable payload — a criterion that cannot fail is not a pin, and pretending otherwise is the defect this decision exists to avoid.

Q#RD12 — The preflight needs a structured Rust-backed seam, not a registry walk alone — NEW at rev 4

Q#RD4 requires the Lua preflight to distinguish absent + ignore (a no-op the preflight must let through) from present + ignore (a real delete the preflight must judge). Q#RD6 specifies only a registry walk, which answers a question about buffers, not about the filesystem. Nothing in Lua closes that gap today:

pmacs.fs.stat (builtin/runtime/fs.lua:133) dispatches through async_mod._dispatch_fs_stat and returns a handle — asynchronous, and the applier is synchronous.
The only synchronous filesystem binding is canonicalize (src/lua_bindings/mod.rs:6743), which is realpath-like and not equivalent to the primitive's symlink_metadata: it resolves symlinks and returns nil for a dangling one, so it reports "absent" for a broken symlink that symlink_metadata reports as present. That is exactly the case this query turns on, so using it would produce a preflight that disagrees with the primitive on the one input that matters.

The seam: one synchronous Rust binding returning a structured verdict, evaluated with the same symlink_metadata call the primitive uses, so the two layers cannot disagree by construction:

Verdict	Meaning
`no-op`	path absent and `ignore_if_not_exists` set — the op will do nothing; the preflight must not reject it
`clear`	the delete may proceed: no matching buffer is modified
`conflict`	at least one matching buffer (at the path, or beneath it for a recursive delete) is modified — refuse, with the buffer named

Error contract. The binding is total over its inputs and does not raise for ordinary filesystem conditions — absence is a verdict, not an error. It raises only on argument-type violations, matching the rest of the pmacs.buffer surface. A stat error that is neither success nor NotFound (e.g. EACCES on a parent directory) yields conflict, not clear: the preflight must never report "safe to delete" on the strength of a question it could not answer. That asymmetry is deliberate — the failure direction is toward refusing.

This binding is the single shared query of Q#RD6: the walk is its buffer half, the symlink_metadata call its filesystem half, and the primitive's validation phase calls the same function so drift is impossible rather than merely discouraged.

4. Bets (falsifiable)

B1 — Refusing breaks no legitimate server workflow. A server deleting a file the user has unsaved edits in is a conflict the user must resolve. Falsified by a real server whose normal operation deletes files the user is actively editing.
B2 — Mid-batch refusal is acceptable because partial application is already what pmacs does, and is safer than data loss. Rewritten at rev 3 (P1-2). Revision 2 rested this on the protocol "assigning Abort" to resource-op edits, which it does not (§1.7): recovery is the client's advertised choice and pmacs advertises none. The bet now stands on repository evidence — §1.6 verified that an op failing mid-batch leaves earlier ops applied on main today — plus the ordering judgement that a partial refactor the user can see and redo beats unsaved work they cannot recover. Falsified if a server is found that requires transactional application and degrades badly under partial application. Acceptance 12 pins the observable behaviour either way.
B3 — Prefix-aware validation does not over-refuse. Falsified if a common workflow deletes a directory while an unrelated modified buffer sits beneath it and the refusal is judged unhelpful.
B4 — Leaving clean descendants orphaned is the lesser evil (Q#RD5). Falsified if orphaned clean buffers after a recursive delete prove more disruptive than the tree-wide lifecycle defect that removing them would create.

5. Acceptance

Each criterion states the pre-image it must fail against. A test that passes against its pre-image has no bite and is rejected.

A delete op targeting a modified buffer refuses, and the file survives. Assert together: the call fails, the buffer is still in the registry with its exact unsaved text, and path.exists() is still true. Bite: fails against ad41cf1 unmodified. Asserting only that the buffer survived is vacuous — that is mode (c)'s existing behaviour. The exists() assertion carries the bite.
A delete op targeting a clean open buffer still succeeds, file removed and buffer removed. Bite: fails against an over-broad guard that refuses whenever a buffer is open. Assert both directions.
A filesystem failure preserves the clean buffer (Q#RD2). Force the fs mutation to fail (e.g. a non-empty directory without recursive) and assert the buffer is still present and intact. Bite: fails against revision 1's buffer-first ordering, which would have removed the buffer and then failed.
on_removed observes the path absent (Q#RD2). Register an on_removed callback that stats the path and records the result; assert it saw the path already gone. Bite: fails against revision 1's buffer-first ordering, under which the callback would observe the file still present. This is the pin that keeps the phase order from silently regressing.
A delete called from inside the target's own edit intercept refuses before disk (Q#RD2). Assert the file still exists. Bite: fails against ad41cf1, where ConcurrentEdit is discovered only at removal time — after remove_file has already run.
Duplicate path-bound buffers cannot hide a modified copy (Q#RD6). Create two buffers on one path via pmacs.buffer.from_file, leave the first clean and modify the second, then delete. Bite: fails against any first-match lookup, including EditorCore::find_buffer_for_path — which is exactly what revision 1 specified. This is the criterion that pins validation breadth; criterion 14 pins the reconciliation half and cannot see breadth (Q#RD10).
Component-prefix false positives are rejected (Q#RD6). A modified buffer under /tree-sibling must not block a recursive delete of /tree. Bite: fails against a string-prefix implementation. Pairs with criterion 8 so both directions of the prefix rule are pinned.
recursive = true over a directory containing a modified buffer's file refuses, and the whole tree survives (Q#RD5). Assert the inner file still exists — not merely that the buffer does, which is already true today (mode (c)). Bite: fails against exact-path-equality validation.
A clean recursive delete leaves descendant buffers orphaned, not removed (Q#RD5). Assert the descendant buffer is still in the registry after a successful recursive delete. Bite: fails against an implementation that widens reconciliation to the tree. This pin exists specifically to stop the parked defect from being enlarged, and it is expected to look odd — it asserts today's imperfect behaviour deliberately.
ignore_if_not_exists = true on an absent path leaves a modified buffer intact (Q#RD4), reproducing mode (b): file removed behind pmacs's back first, then the op. Bite: fails against a fix guarding only the branch where the fs delete actually ran.
Absent-plus-ignore succeeds through the real server pump (Q#RD4, layer 2). Drive it end to end and assert the batch is not refused and the server is told applied = true. Bite: fails against a preflight that rejects on the presence of a modified buffer without consulting ignore_if_not_exists — the false-positive Q#RD4 exists to prevent.

11a. Present-plus-ignore with a modified buffer is still REFUSED in the preflight (Q#RD4, Q#RD12) — the opposite direction of 11. The target exists on disk, ignore_if_not_exists = true, and a modified buffer is bound to it. Assert the batch is refused, the file still exists, and the buffer keeps its text. Bite: fails against a preflight that treats ignore_if_not_exists as an unconditional bypass rather than consulting the filesystem — i.e. against any implementation that reads the flag without the symlink_metadata verdict Q#RD12 specifies. Revision 3 shipped only direction 11, and one-direction coverage on a two-direction rule is exactly how that gap survived a round; the pair is now explicit, as with 7/8.

11b. A dangling symlink counts as present (Q#RD12). Target is a symlink whose destination does not exist, ignore_if_not_exists = true, modified buffer bound to the link path. Assert refusal. Bite: fails against a preflight built on canonicalize (src/lua_bindings/mod.rs:6743), which returns nil for a broken symlink and would therefore mis-classify this as absent — the one input on which realpath and symlink_metadata disagree, and the reason Q#RD12 specifies the latter.

Edit-then-delete and rename-into-delete still answer the server (Q#RD3, Q#RD7). Two batches that defeat the snapshot preflight: one where an earlier text edit dirties the buffer a later op deletes, one where an earlier rename moves a modified buffer into a later delete's subtree. Assert in both cases that the server receives applied = false with a non-empty failureReason. Bite: fails against ad41cf1 (the raise is swallowed at lsp.lua:1892 and no response is sent) and against a preflight-only fix that claims atomicity — these are the cases revision 1's atomicity claim asserted could not happen.
The refusal reaches the server on the unattended path AND leaves the durable trace (Q#RD7). Assert both: the server receives applied = false with a non-empty failureReason, and *errors* contains a record carrying the lsp:workspace/applyEdit label. The user-initiated paths additionally report on the status line naming the buffer. Bite: fails against a fix that refuses by raising. A direct-call test on apply_resource_op does not satisfy this and is rejected as insufficient — the guard must be pinned through the outermost user-reachable seam. The *errors* half fails against revision 2, which promised the trace and tested only the response; asserting the response alone is what let that gap survive a round.
Clean duplicates: one match reconciled (Q#RD10). Two clean buffers bound to one path; delete succeeds. Assert exactly one is removed and one remains. Bite: fails against an implementation that removes all matches — i.e. it pins the reconciliation half of Q#RD10, and only that. Correction at rev 4: revision 3 claimed this criterion "fails in both directions", including against first-match-only validation. That was false. With both buffers clean there is no verdict difference between consulting one match and consulting all, so the setup cannot see validation breadth. Criterion 6 is the one that detects incomplete validation (clean first, modified second), and the two are now labelled by which half of Q#RD10 each pins. The claim is fixed rather than the setup, because criterion 6 already covers the other half and duplicating it here would add no bite.
Defensive: a parse failure still attempts a response (Q#RD7, Q#RD11). Substitute an explicit throwing test stub for pmacs.lsp._parse_workspace_edit, then assert the server still receives applied = false with a failureReason. Bite: fails against a wrap that covers apply_workspace_edit only, leaving the parse one line outside. Labelled defensive, and here is why the label is load-bearing: revision 3 specified this as a payload test, which could not fail — from_lsp_value (src/rename.rs:95) returns Self and its doc says a shapeless result yields an empty response, and the binding's only ? is lua_to_json over a value that arrived through json_to_lua. No server payload reaches the failure. The stub is therefore substituted deliberately, and the criterion claims only what a stub can establish: that the boundary reports rather than that a server can provoke it.
m4_15_workspace_edit_resource_ops_apply_in_order stays green unmodified, pinning no-regression from outside. Its c.rs is never opened, so it exercises exactly the unguarded case that must keep working (Q#RD6).
Every new test is checked with scripts/bite and none reports VACUOUS.

6. Parked — not deferred-and-forgotten

Mode (d): the dangling window and the emptiable registry (§1.1, Q#RD8). Owned by #171 as of its revision 7 — reconcile_delete composes both removal phases and reroutes apply_resource_op's delete arm through it. Revision 2 of this document called it unowned; that was true when written and is not now. Q#RD5 and Q#RD10 are written to avoid enlarging what that lane must fix.
pmacs.fs.remove is guarded by neither lane — explicitly out of scope here (named in #171 revision 7 §11). After both lanes land, the refusal sits at the apply_resource_op primitive (this lane) and in dired's policy layer (#171), but pmacs.fs.remove is public Lua API with no dirty check of its own, so a third caller inherits neither guard — the guards are one layer above it on each side. Verified latent rather than live: pmacs.fs.remove (builtin/runtime/fs.lua:187) has zero production callers, its only references being tests/m8_1_acceptance.rs:438, :439, :472. This lane does not extend scope to cover it. It belongs with the primitive-level fs guards, i.e. #171's pmacs.fs.* work or a successor lane — recorded here because "both lanes guard deletion" otherwise reads as a claim that the primitive is guarded, and it is not.
kill_buffer and editor.quit have the same gap (§1.4). editor.before-quit exists as a veto channel with no subscriber. This lane sets the precedent; those are separate lanes.
Declaring workspace.workspaceEdit capabilities — documentChanges, resourceOperations, failureHandling (§1.11). Declaring them changes what servers send, so it needs its own evidence and its own lane.
pmacs.error is undefined (§1.5) — 11 dead call sites in builtin/, including the one that is supposed to surface every uncaught async coroutine error. A known standing defect, widened in relevance by this framing but not fixed by it.
A y_or_n helper, minibuffer queuing, and a held-server-request ledger — the three prerequisites that would make §2.2 cheap rather than merely expensive.
lsp.confirm-server-edits, the config-registry adopter that would let a user loosen Q#RD1 once a prompt mechanism exists.
The rename side of prefix-aware, normalizing lookup — dired Stage 2's, per Q#RD5.

7. Gates

Full suite per CLAUDE.md: cargo fmt --check; cargo clippy --workspace --all-targets -- -D warnings as its own step; cargo test --lib; cargo test --lib --features crdt; the touched acceptance suites; cargo test --test m4_acceptance -- --skip basedpyright; PMACS_REQUIRE_GPU=1 cargo test -p pmacs-gpu; git diff --check.

Touched suites: m4_acceptance (the resource-op home, §1.14, and the home of criteria 1–14 and 16) and lsp_dispatch_seams_acceptance (criterion 15's throwing parse stub, Q#RD11). Both appear in §8's touch table; revision 3 named the second here but omitted it there, and the two lists are now maintained together.

dired_acceptance and autosave_acceptance are watch items, not touched files — the former for Q#RD6's shared lookup, the latter because on_removed ordering (criterion 4) is where autosave's discard_buffer hangs.

Gate the pushed tree, not the worktree — commit first, then gate.

While the document is still PROPOSED the gate is git diff --check plus a docs read; the full suite runs once implementation lands on this branch.

8. Branch plan

resource-op-delete-guard, worktree ../pmacs-resource-op-delete, one branch, one PR — #186, which becomes the implementation PR. Revision 2 withdraws revision 1's two-PR plan, which conflicted with one-feature/one-branch/one-PR: the framing is revised in place, and once approved the implementation commits land on this same branch.

Implementation does not begin until the user approves this revision.

Files the implementation will touch — reconciled at rev 4 against the gate list below and §5, which revision 3 left disagreeing:

File	Why
`src/lua_bindings/mod.rs`	the delete arm's four phases (Q#RD2); the shared query binding and its structured verdict (Q#RD6, Q#RD12); the narrow `errors` append surface (Q#RD7)
`builtin/runtime/lsp.lua`	the preflight conflict check (Q#RD3); the parse-plus-apply wrap, origin restore, and boundary logging (Q#RD7)
`tests/m4_acceptance.rs`	criteria 1–14, 16
`tests/lsp_dispatch_seams_acceptance.rs`	criterion 15's throwing parse stub (Q#RD11) — this file was named in the gate list but omitted from revision 3's touch list
`src/bin/pmacs_fake_lsp.rs`	fake modes: blocked delete; edit-then-delete; rename-into-delete; absent-plus-ignore; present-plus-ignore (11a); dangling-symlink (11b)

It will not touch src/daemon.rs, pmacs-protocol/, builtin/runtime/dired.lua, docs/agent-handoff.md or COHERENCE.md. No protocol change.

If criterion 15's stub proves cleaner to host in m4_acceptance alongside the rest, that is a permitted simplification — but then lsp_dispatch_seams_acceptance drops out of the gate list too, and the two lists move together. Revision 3's defect was that they did not.

Ownership note — restated at rev 3 against #171 revision 7. The settled split is quoted in §1.12 and Q#RD5 and is carried identically by both lanes. Concretely, this lane claims for its duration:

the pre-filesystem refusal inside synchronous apply_resource_op;
the shared walk query of Q#RD6 (whichever lands first owns the query), which #171 then adopts for reconcile_rename;
builtin/runtime/lsp.lua's apply_workspace_edit and the workspace/applyEdit server-request boundary.

It explicitly does not claim: full post-delete lifecycle reconciliation, the dired async race between dispatch and remove_blocking, the rename side of the walk, or pmacs.fs.remove (§6). Revision 2's version of this note was written against a stale reading of #171 and is superseded.

80 KiB Raw Blame History Unescape Escape

Framing — apply_resource_op delete destroys unsaved work