Expand leading ~ in Codex home paths before exporting CODEX_HOME

[altjx]

Summary

Spawned processes don't inherit shell tilde expansion, so a Codex homePath of ~/.codex-work in the server settings was being passed to the child Codex process verbatim as CODEX_HOME=~/.codex-work. The receiver then treats ~ as a relative directory name rather than $HOME, so state ends up in the wrong place (or fails to load existing config).

This PR adds a small expandHomePath() helper and applies it everywhere the Codex homePath setting flows into a CODEX_HOME env var passed to a spawned child:

• CodexAppServerManager spawn + CLI version check
• CodexTextGeneration spawn
• CodexProvider.runCodexCommand spawn (health check)
• probeCodexDiscovery spawn

The helper handles ~ alone, ~/…, and ~\… — matching the behavior of the other three expandHomePath implementations already in the tree (os-jank.ts, WorkspaceEntries.ts, WorkspacePaths.ts). Only ~ and ~//~\ are expanded; ~user (other-user) is intentionally left alone, same as the existing helpers.

Notes for reviewers

• Scope is narrow on purpose: only the CODEX_HOME env var that gets propagated to child processes. readCodexConfigModelProvider in CodexProvider.ts also uses homePath as a direct filesystem path (for config.toml) and has the same latent bug, but that's a separate read path — happy to fold that in if you'd prefer a single PR, or leave as a follow-up.
• There are now four expandHomePath helpers in apps/server/src/. Consolidating them is an easy follow-up, but I kept this PR focused on the user-visible bug. The new helper is a plain function (not Effect-based) because some of the call sites (probeCodexDiscovery, parts of codexAppServerManager) are plain async functions.

Test plan

• vitest run src/pathExpansion.test.ts — new unit tests (empty, ~, ~/…, ~\…, ~user pass-through, non-tilde pass-through) all pass
• vitest run for the touched files (codexAppServerManager.test.ts, CodexTextGeneration.test.ts, pathExpansion.test.ts) — 60 passing, 1 skipped, 0 failing
• tsc --noEmit clean
• Manually verified locally: Codex sessions with homePath: ~/.codex-work now land in the correct home directory instead of a literal ~ folder

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Note

Low Risk
Low risk: a small, well-tested path normalization helper applied only to CODEX_HOME env propagation for spawned Codex CLI/app-server processes.

Overview
Fixes Codex homePath values like ~/.codex-work being passed literally to child Codex processes by expanding a leading ~ before exporting CODEX_HOME.

Adds a new expandHomePath() utility (with unit tests) and applies it across all Codex process spawn points, including app-server startup, CLI version checks, provider health checks, discovery probing, and Git text generation.

^{Reviewed by Cursor Bugbot for commit 3463ac5. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Expand leading ~ in CODEX_HOME paths before passing to Codex CLI subprocesses

Adds a new expandHomePath utility in pathExpansion.ts that resolves a leading ~, ~/, or ~\ to the current user's home directory via os.homedir(). Applies this expansion to CODEX_HOME in all locations where Codex CLI subprocesses are spawned: the app-server session, version check, text generation, provider command execution, and discovery probing.

^{Macroscope summarized 3463ac5.}

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[macroscopeapp]

Approvability

Verdict: Approved

Straightforward bug fix that expands ~ in paths before passing them to spawned processes. The new utility function is simple, well-tested, and applied consistently across all CODEX_HOME usages. No complex logic or side effects beyond fixing incorrect path handling.

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