Cloud terminals: Option+Backspace word delete, and close the pane when the shell exits - #12099
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… DEL A cloud terminal pane is a manual-I/O mirror surface: Ghostty encodes the key and hands the bytes to the remote shell instead of a local PTY. The remote shell binds ESC DEL to backward-kill-word, so that is the byte sequence the surface must emit. Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3
ble.sh queries the terminal at startup; once its DA2 reply completes terminal identification it switches to xterm modifyOtherKeys. From that point Alt+Backspace does nothing: ble.sh no longer honors the legacy ESC DEL binding, and its decode of the modifyOtherKeys form (CSI 27;3;127~) does not reach M-C-?. Letters are unaffected, which is why Alt+d and Alt+u kept working. The same break reproduces under tmux, so it is not specific to the cmux terminal host. Pin ble.sh to the legacy encoding, which the Ghostty cloud pane sends by default, and bind both backspace spellings explicitly. Verified against the real /etc/cmux/bashrc in an Ubuntu container running the same ble.sh nightly, hosted by a cmux-tui daemon: before, ESC DEL and CSI 27;3;127~ were both no-ops; after, ESC DEL and ESC BS each kill the previous word. Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3
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📝 WalkthroughWalkthroughThe change adds macOS coverage for Option+Delete encoding and configures ble.sh in the devbox image to handle both legacy Alt+Backspace sequences. ChangesAlt-Backspace support
Estimated code review effort: 3 (Moderate) | ~20 minutes Merge Risk: 🟡 Moderate · up to This restores Option+Backspace word deletion in cloud terminals, but the new serialized input test can hang when input is not received as expected, risking stalled test execution until its synchronization is made completion-driven and bounded. Sequence Diagram(s)sequenceDiagram
participant NSWindow
participant TerminalSurface
participant ble.sh
participant Bash
NSWindow->>TerminalSurface: Send Option+Delete
TerminalSurface->>ble.sh: Emit legacy ESC DEL
ble.sh->>Bash: Apply kill-backward-cword
Bash-->>ble.sh: Delete the previous word
Suggested reviewers: Important Pre-merge checks failedPlease resolve all errors before merging. Addressing warnings is optional. ❌ Failed checks (2 errors, 2 warnings)
✅ Passed checks (21 passed)
Full details: Docstring CoverageExplanation Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files. (2 skipped: 2 unsupported.) Full details: Cmux User-Facing Error PrivacyExplanation The pull request adds user-visible control-socket API errors that expose implementation details. Resolution Sanitize the authorization API responses before encoding them. Replace Full details: Cmux Architecture RethinkExplanation The PR adds a production timing and lock workaround for the remote PTY lifecycle. Resolution Move the PTY-close operation, deadline/cancellation state, and completion transition into
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In `@cmuxTests/CloudManualInputOptionBackspaceTests.swift`:
- Line 55: Replace the fixed RunLoop delay and unbounded iterator loop in the
test with an input completion created before sending the key; have
manualInputHandler resume it on the first input event, await it through the test
harness completion mechanism, then assert the received bytes while retaining a
deadline-bounded wait.
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A cloud terminal pane owns no process, so nothing local noticed when the remote shell ended. After Ctrl+D or `exit` the daemon dropped the tab and marked the terminal exited, the byte attachment reported `detached`, and the pane kept reconnecting behind a frozen screen that swallowed input. The accepted graph is the signal. After each publication, panes whose terminal is gone from a current graph close, through the same close path the menu, the CLI, and the shortcut use. A stale graph closes nothing: an unreachable machine reports no terminals, and that is a lost link, not an exited shell. Two details the first attempt got wrong, both found by driving a real Cloud VM: the socket close refuses a workspace's last surface, which is exactly the shape `cmux vm workspace new` creates, and closing only the tab there leaves the workspace to open a fresh local shell in the cloud pane's place. A single-pane workspace now closes with its pane, which is what a local workspace does when its last shell exits. The resolver also learns to report an exited terminal instead of conflating it with a live terminal that has no view (both answer `surface:null`). Verified on a Freestyle Cloud VM through a tagged build: a single-pane cloud workspace closes on Ctrl+D, a cloud pane split beside another pane closes alone, and both cases previously stayed open and frozen. Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3
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The Option+Backspace test awaited an AsyncStream with no deadline, so a surface that never encoded the key would hang the run instead of failing it. Race the first input against a timeout. `closeExited` keeps its pane-close fallback for a workspace that refuses to close; the comment now says why that is still the better outcome. Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3
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b3991d6 Make main's unit test bundle compile again (revert test-only manaflow-ai#11929, wire tmux helpers) (manaflow-ai#12113) 398a10f cmux-tui: durable agent notifications with per-client read state (notification.ack) (manaflow-ai#12108) f0a9407 dashboard: one coderouter accounts list and a sidebar team switcher (manaflow-ai#12103) 16a0e2c Cloud terminals: Option+Backspace word delete, and close the pane when the shell exits (manaflow-ai#12099) dfb0a6f cloud: trust codex and Claude Code everywhere in the devbox; drop dead token-rendering driver code (manaflow-ai#12102)
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…n the shell exits (manaflow-ai#12099) * test: assert cloud manual-mirror panes encode Option+Backspace as ESC DEL A cloud terminal pane is a manual-I/O mirror surface: Ghostty encodes the key and hands the bytes to the remote shell instead of a local PTY. The remote shell binds ESC DEL to backward-kill-word, so that is the byte sequence the surface must emit. Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3 * fix(cloud): restore Option+Backspace word delete in cloud terminals ble.sh queries the terminal at startup; once its DA2 reply completes terminal identification it switches to xterm modifyOtherKeys. From that point Alt+Backspace does nothing: ble.sh no longer honors the legacy ESC DEL binding, and its decode of the modifyOtherKeys form (CSI 27;3;127~) does not reach M-C-?. Letters are unaffected, which is why Alt+d and Alt+u kept working. The same break reproduces under tmux, so it is not specific to the cmux terminal host. Pin ble.sh to the legacy encoding, which the Ghostty cloud pane sends by default, and bind both backspace spellings explicitly. Verified against the real /etc/cmux/bashrc in an Ubuntu container running the same ble.sh nightly, hosted by a cmux-tui daemon: before, ESC DEL and CSI 27;3;127~ were both no-ops; after, ESC DEL and ESC BS each kill the previous word. Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3 * fix(cloud): close a cloud pane when its remote shell exits A cloud terminal pane owns no process, so nothing local noticed when the remote shell ended. After Ctrl+D or `exit` the daemon dropped the tab and marked the terminal exited, the byte attachment reported `detached`, and the pane kept reconnecting behind a frozen screen that swallowed input. The accepted graph is the signal. After each publication, panes whose terminal is gone from a current graph close, through the same close path the menu, the CLI, and the shortcut use. A stale graph closes nothing: an unreachable machine reports no terminals, and that is a lost link, not an exited shell. Two details the first attempt got wrong, both found by driving a real Cloud VM: the socket close refuses a workspace's last surface, which is exactly the shape `cmux vm workspace new` creates, and closing only the tab there leaves the workspace to open a fresh local shell in the cloud pane's place. A single-pane workspace now closes with its pane, which is what a local workspace does when its last shell exits. The resolver also learns to report an exited terminal instead of conflating it with a live terminal that has no view (both answer `surface:null`). Verified on a Freestyle Cloud VM through a tagged build: a single-pane cloud workspace closes on Ctrl+D, a cloud pane split beside another pane closes alone, and both cases previously stayed open and frozen. Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3 * review: bound the manual-input wait and state the last-pane fallback The Option+Backspace test awaited an AsyncStream with no deadline, so a surface that never encoded the key would hang the run instead of failing it. Race the first input against a timeout. `closeExited` keeps its pane-close fallback for a workspace that refuses to close; the comment now says why that is still the better outcome. Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3 * review: match the optional input with if-let Claude-Session: https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3
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Two cloud terminal bugs, both verified on a real Freestyle Cloud VM through a tagged build.
Option+Backspace did nothing
ble.sh (the devbox bash line editor) queries the terminal at startup. Once the DA2 reply completes terminal identification, ble.sh switches to xterm modifyOtherKeys, and from that point Alt+Backspace is dead: the legacy
ESC DELbinding is gone and ble.sh's decode of the modifyOtherKeys form (CSI 27;3;127~) does not reachM-C-?. Alt+d and Alt+u keep working because letters decode fine. The same break reproduces under tmux, so it is upstream ble.sh behavior, not something specific to the cmux terminal host./etc/cmux/bashrcnow pins ble.sh to the legacy encoding and binds both backspace spellings.How it was found: a cmux-tui daemon hosting an Ubuntu container with the same ble.sh nightly reproduces it exactly, and a plain PTY hosting the same container does not. Injecting bytes through the daemon's manual-I/O attach (the path a cloud pane uses) showed
ESC DEL,ESC BS,CSI 27;3;127~andCSI 127;3uall no-ops whileC-wworked.The first commit adds the macOS-side contract this depends on: a cloud manual-mirror pane encodes Option+Backspace as
ESC DEL(0x1B 0x7F). It passes oncmuxTests/CloudManualInputOptionBackspaceTests(fleet mini, schemecmux-unit).Tradeoff: ble.sh's line editor loses modifyOtherKeys, so it can no longer tell chords such as Shift+Enter apart at the bash prompt. Programs started inside the terminal set their own modes and are unaffected.
Deploy note:
cmux-bashrcis baked into the devbox image, so this reaches machines only after a devbox rebake and snapshot promotion. Existing VMs keep the old shell config.Ctrl+D left a dead pane on screen
A cloud pane owns no process, so nothing local noticed when the remote shell ended. The daemon dropped the tab and marked the terminal exited, the byte attachment reported
detached, and the pane kept reconnecting behind a frozen screen that swallowed input.The accepted graph is now the signal: after each publication, panes whose terminal is gone from a current graph close through the shared close path. A stale graph closes nothing, because an unreachable machine reports no terminals and that is a lost link, not an exited shell.
Two details only a live VM exposed: the socket close refuses a workspace's last surface, which is exactly the shape
cmux vm workspace newcreates, and closing only the tab there leaves the workspace to open a fresh local shell in the cloud pane's place. A single-pane cloud workspace now closes with its pane, matching a local workspace when its last shell exits.Live verification (tagged build, Freestyle VM): single-pane cloud workspace closes on Ctrl+D; a cloud pane split beside another pane closes alone and leaves the workspace;
echo hello world+ Option+Backspace leavesecho hello.https://claude.ai/code/session_01GQSu7X1ybGzWsfGKgG8jn3
Note
Medium Risk
Touches workspace/pane teardown and graph-driven closure; incorrect freshness or resolver handling could close panes while a machine is merely unreachable, though stale graphs are explicitly guarded.
Overview
Fixes two cloud-terminal UX issues: dead panes after the remote shell exits, and Option+Backspace doing nothing in devbox shells.
Pane closure when the shell ends. The resolver now treats
lifecycle: "exited"separately from a live zero-view terminal (surface:null), propagating an.exitedoutcome through parsing and surface-ID resolution. Manual-mirror refresh stops reconnecting exited terminals and closes those panes immediately; after each current VM graph publish,CloudTerminalPaneClosurecloses attach panes whose terminal keys are no longer in the graph (stale graphs close nothing).SurfacePaneFactory.closeExitedforce-closes the pane—and the whole workspace when it is the only pane—bypassing the socket rule that blocks closing a workspace’s last surface.Option+Backspace. Adds a unit test that manual-mirror surfaces emit
ESC DELfor Option+Delete. Devboxcmux-bashrcdisables ble.shmodifyOtherKeysand binds backward word-delete for the legacy encoding cloud panes send.Reviewed by Cursor Bugbot for commit f447743. Bugbot is set up for automated code reviews on this repo. Configure here.