fix(desktop): recognise how real tmux before 3.0 refuses pane options, and use a separator no field can straddle

- Real tmux 2.9a refuses `set-option -p` with its own getopt's
  `unknown option -- p` and set-option's usage line (BSD getopt on macOS:
  `illegal option -- p`). The untracked fallback only matched later wordings,
  so on real pre-3.0 tmux every run was refused. The fake tmux and the tests
  now use the text captured from real 2.9a.
- The `-F` separator `|~sim~|` began and ended with the same character, so a
  field ending in `|~sim~` was misread rather than dropped. `<~sim~>` has no
  proper prefix that is also a suffix, so it is only found where it was
  written or wholly inside a field, whose line is then dropped.

Author: waleedlatif1

apps/desktop/src/main/terminal/tmux.test.ts

@@ -16,13 +16,33 @@ import {
   type TmuxRunHandle,
 } from '@/main/terminal/tmux'
 
+/** What real tmux 2.9a writes for `set-option -p`, captured from the binary. */
+const TMUX_29_NO_PANE_OPTIONS =
+  'tmux: unknown option -- p\nusage: set-option [-aFgosquw] [-t target-window] option [value]\n'
+/** The same refusal from a tmux built against BSD getopt, as on macOS. */
+const TMUX_29_BSD_NO_PANE_OPTIONS =
+  'tmux: illegal option -- p\nusage: set-option [-aFgosquw] [-t target-window] option [value]\n'
+
 /** The separator the format strings use. */
-const F = '|~sim~|'
+const F = '<~sim~>'
 
 describe('parseFormatLines', () => {
   it('drops lines with the wrong field count rather than mis-assigning them', () => {
     expect(parseFormatLines(`a${F}b\nonly-one\n`, 2)).toEqual([['a', 'b']])
   })
+
+  it('reads a field that ends with part of the separator as it is', () => {
+    // A cwd or window name may end with any text, including all but the separator's last character.
+    const partial = F.slice(0, -1)
+    expect(parseFormatLines(`/tmp/x/p${partial}${F}1\n`, 2)).toEqual([[`/tmp/x/p${partial}`, '1']])
+    expect(parseFormatLines(`tail${partial}${F}%3${F}zsh\n`, 3)).toEqual([
+      [`tail${partial}`, '%3', 'zsh'],
+    ])
+  })
+
+  it('drops a line whose field holds the whole separator rather than misread it', () => {
+    expect(parseFormatLines(`a${F}b${F}c\n`, 2)).toEqual([])
+  })
 })
 
 describe('isDescendantOf', () => {
@@ -108,10 +128,6 @@ interface FakeTmuxState {
   fail?: Record<string, string>
   /** Attached clients, as `list-clients` reports them. */
   clients?: Array<{ pid: string; tty: string; session: string }>
-
-  /** Commands the fake answers only after this many milliseconds, like a busy tmux server. */
-  delay?: Record<string, number>
-
   /** Commands the fake holds until the file named here exists, like a busy tmux server. */
   hold?: Record<string, string>
   /** Commands the fake is holding right now. */
@@ -132,10 +148,6 @@ const escaped = (text) =>
   text
     .replace(/\\\\/g, '\\\\\\\\')
     .replace(/[\\x00-\\x1f]/g, (c) => '\\\\' + c.charCodeAt(0).toString(8).padStart(3, '0'))
-
-if (state.delay && state.delay[args[0]]) {
-  Atomics.wait(new Int32Array(new SharedArrayBuffer(4)), 0, 0, state.delay[args[0]])
-
 if (state.hold && state.hold[args[0]]) {
   state.held = [...(state.held ?? []), args[0]]
   save()
@@ -315,9 +327,12 @@ describe('stopping a tmux run touches only its own pane', () => {
     expect(tmux.read().log).toEqual([])
   })
 
-  it.each(['invalid option: @sim-run-id', 'unknown flag -p'])(
+  it.each([
+    ['tmux 2.9a', TMUX_29_NO_PANE_OPTIONS],
+    ['BSD getopt', TMUX_29_BSD_NO_PANE_OPTIONS],
+  ])(
     'starts a run untracked on a tmux without pane options (%s), and never stops it by a pane id',
-    async (refusal) => {
+    async (_build, refusal) => {
       const tmux = fakeTmux()
       dirs.push(tmux.dir)
       // tmux before 3.0 has no pane options.
@@ -360,7 +375,7 @@ describe('stopping a tmux run touches only its own pane', () => {
   it("closes a finished untracked run's pane, and only once it has finished", async () => {
     const tmux = fakeTmux()
     dirs.push(tmux.dir)
-    tmux.write({ ...tmux.read(), fail: { 'set-option': 'invalid option: @sim-run-id' } })
+    tmux.write({ ...tmux.read(), fail: { 'set-option': TMUX_29_NO_PANE_OPTIONS } })
     const run = await startRun('agent', 'make build', null, tmux.env)
     if ('error' in run) throw new Error(run.error)
 
@@ -376,7 +391,7 @@ describe('stopping a tmux run touches only its own pane', () => {
   it("never closes a pane that took a finished untracked run's id after tmux restarted", async () => {
     const tmux = fakeTmux()
     dirs.push(tmux.dir)
-    tmux.write({ ...tmux.read(), fail: { 'set-option': 'invalid option: @sim-run-id' } })
+    tmux.write({ ...tmux.read(), fail: { 'set-option': TMUX_29_NO_PANE_OPTIONS } })
     const run = await startRun('agent', 'make build', null, tmux.env)
     if ('error' in run) throw new Error(run.error)
     writeFileSync(run.statusPath, '0')
@@ -425,7 +440,7 @@ describe('stopping a tmux run touches only its own pane', () => {
 
     const untagged = fakeTmux({ exec: true })
     dirs.push(untagged.dir)
-    untagged.write({ ...untagged.read(), fail: { 'set-option': 'invalid option' } })
+    untagged.write({ ...untagged.read(), fail: { 'set-option': TMUX_29_NO_PANE_OPTIONS } })
     const untracked = await startRun('agent', 'echo ran', null, untagged.env)
     if ('error' in untracked) throw new Error(untracked.error)
     await expect

apps/desktop/src/main/terminal/tmux.ts

@@ -41,10 +41,11 @@ const RUN_POLL_INTERVAL_MS = 250
 /**
  * Field separator for `-F` output. Printable on purpose: tmux 3.4 and 3.5 print a control
  * character as its octal escape, so a control-character separator arrived as the text `\037` and
- * no line split. No tmux escapes these characters, and a field that happened to contain the
- * separator would change the line's field count, so that line is dropped rather than misread.
+ * no line split. No tmux escapes these characters. No proper prefix of the separator is also a
+ * suffix of it, so it can only be found where it was written or wholly inside a field: a field
+ * holding it changes the line's field count, and that line is dropped rather than misread.
  */
-const FIELD = '|~sim~|'
+const FIELD = '<~sim~>'
 
 export interface TmuxCommandResult {
   ok: boolean
@@ -330,8 +331,13 @@ const RUN_GATE_POLLS = Math.ceil((2 * TMUX_TIMEOUT_MS + 5_000) / 50)
 /** The tmux user option that marks a pane as one run's own. */
 const RUN_ID_OPTION = '@sim-run-id'
 
-/** How tmux before 3.0, which has no pane options, refuses `set-option -p`. */
-const NO_PANE_OPTIONS = /unknown flag|invalid option/i
+/**
+ * How tmux before 3.0, which has no pane options, refuses `set-option -p`. Its own getopt prints
+ * `unknown option -- p` (BSD getopt on macOS: `illegal option -- p`) followed by set-option's usage
+ * line; later wordings are kept for any build that phrases it so.
+ */
+const NO_PANE_OPTIONS =
+  /unknown option -- p|illegal option -- p|usage: set-option|unknown flag|invalid option/i
 
 /**
  * Starts a command in a dedicated tmux window.