iOS input fails in 0.21.34+ when Apple tools resolve past a stale Xcode selection symlink

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#4,145 0 comentarios 0 reacciones 0 asignados Ver en GitHub

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@thymikee ya está trabajando en esto.

Desde el 1/11/2026.

  • #4146 de @thymikee — abierto

Evaluación

Dificultad
4/5
Tiempo estimado
3-5 días
Aptitud para principiantes
22/100
Tipo de issue
Error
Claridad
Bastante claro
Estado de actividad
Activo
Stack tecnológico
ios, macos, typescript
Área
mobile-dev

Línea de trabajo

Start in packages/platform-apple/src/runner/runner-toolchain-identity.ts, where selectionLinkTarget() throws on a dangling /var/db/xcode_select_link, then read its test at src/runner/tests/runner-toolchain-identity.test.ts lines 68-79, which enforces that assumption. Run that test file to see the current failure. Done means a stale legacy link no longer blocks input when the active developer directory resolves. Open PR #4146 already targets this, so check it before starting.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

agent-device 0.21.35 rejects iOS input on a Mac where Apple's tools successfully resolve the current Xcode, because an obsolete /var/db/xcode_select_link still points at a deleted installation. The same interaction succeeds with 0.21.33 on the unchanged machine.

Environment

  • macOS 27.0.1, build 26A434, Apple Silicon
  • Xcode 27.0, build 27A266a, installed at /Applications/Xcode.app
  • iOS Simulator 27.0; tested on an iPhone 18 Pro simulator
  • Node.js 22.20.0
  • DEVELOPER_DIR is unset
  • Tested versions: 0.21.33 passes, 0.21.35 fails

Toolchain state

The obsolete symlink exists, but its target no longer exists:

/var/db/xcode_select_link -> /Applications/Xcode-16.2.0.16C5032a.app/Contents/Developer

Apple's tools resolve the installed Xcode successfully, including with an empty environment:

$ env -i PATH=/usr/bin:/bin /usr/bin/xcode-select -p
/Applications/Xcode.app/Contents/Developer

$ env -i PATH=/usr/bin:/bin /usr/bin/xcrun --find xcodebuild
/Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild

$ xcodebuild -version
Xcode 27.0
Build version 27A266a

$ xcrun --sdk iphonesimulator --show-sdk-version
27.0

$ xcrun --sdk iphonesimulator --show-sdk-build-version
24A430

Reproduction

On a Mac with the toolchain state above, use agent-device 0.21.35's MCP server and a booted iOS simulator:

  1. Call open with a named session, platform: "ios", the simulator's udid, and app: "com.apple.Preferences".
  2. Call snapshot with that session and interactiveOnly: true.
  3. Call press on the current snapshot ref for General, with settle: true.

open and snapshot succeed. screenshot also succeeds. press fails before dispatch:

code: COMMAND_FAILED
reason: apple_toolchain_unreadable
file: /var/db/xcode_select_link
detail: dangling selection link
dispatched: no

The error says it could not read the Xcode toolchain versions used for the Apple runner cache key, and suggests checking xcode-select -p or DEVELOPER_DIR. xcode-select -p already reports the working installation above.

Version comparison

With 0.21.33, on the same booted simulator and with no DEVELOPER_DIR override or system configuration changes, I verified:

  • Open Settings and read its accessibility snapshot.
  • Press General and verify that About appears on the resulting screen.
  • Navigate back and close the session.

After pinning Mobile Dev to 0.21.33, I repeated the interaction through its packaged Claude server, including a screenshot and a batch command; all passed without an Xcode override.

Regression source

This comes from #3995, first included in 0.21.34. The published 0.21.34 and 0.21.35 packages contain the new identity reader; 0.21.33 does not. The live failing interaction above was tested on 0.21.35.

selectionLinkTarget() in v0.21.35 throws when the legacy symlink cannot be resolved. Its assumption that a dangling link means Apple cannot resolve a working developer directory does not hold on this machine. The corresponding test explicitly enforces that assumption.

I understand the change avoids stalled xcrun probes on hosted runners. The remaining correctness requirement is that the cache fingerprint identify the same Xcode that Apple's tools actually use. A stale legacy symlink should not block device input when the active developer directory resolves successfully.

Lenguaje dominante
TypeScript
Estrellas
5.2k
Forks
359
Merge medio
13 h 31 min
PR fusionados (30 d)
664

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