dsh-git-bash

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Built for dsh-TUI.

Make a Git for Windows installation resolvable as bash inside the dsh host process, so the official bash shell stack can run on Windows.

The problem it solves

dsh ships two shell stacks and gates them by platform: on Windows @deepseek-ai/dsh-base mounts pwsh-sandbox + tool-pwsh and disables bash-sandbox + tool-bash. The bash stack is not disabled for lack of support — it is disabled because it spawns the bare name bash:

• the executor runs ["bash", "-c", command], and
• the sandbox layer builds its own ["bash", "-c", command] for the confined runner.

Neither place accepts a configurable executable path. A stock Windows PATH does not resolve bash: Git for Windows puts cmd\git.exe on PATH, but not bin\bash.exe. So the only seam that reaches both spawn sites is the process PATH — which is what this plugin edits.

What it does

On win32 only, during apply():

1. detects a Git installation (%ProgramFiles%\Git\bin, %ProgramFiles(x86)%\Git\bin, %LOCALAPPDATA%\Programs\Git\bin, then C:\Program Files\Git\bin) and checks that it really holds bash.exe;
2. prepends that directory to process.env.PATH — but only when bash is not resolvable already, and never reordering an existing entry;
3. records what it decided in ~/.dsh-tui/dsh-git-bash.log (bounded: past 128 KiB the older half is dropped, and node --test runs never write it);
4. restores the previous PATH on unload — but only while the value is still its own, so a PATH someone else edited afterwards is left alone.

On other platforms it logs skipped: not win32 and does nothing.

It never throws: a missing installation, an unreadable log or a hostile config leaves the host exactly as it was.

Enabling the bash stack: the bundle patch does both halves

A plugin cannot register a tool; it can only make the environment the official tools need. So this package's own bundle patch does both halves, and installing the package IS the installation:

- insert:
    - id: dsh-git-bash
      name: 'dsh-git-bash'
- id: bash-sandbox      # enabled (config restated: a patch replaces it whole)
  disabled: false
- id: pwsh-sandbox      # disabled
  disabled: true
- id: tool-bash         # enabled -> the `bash` tool appears
  disabled: false
- id: tool-pwsh         # disabled
  disabled: true

Both stacks provide ctx.shell, so exactly one may mount: this is a swap, not an addition. pwsh remains reachable from bash (powershell -Command '…') if you need it.

Reverting is removing the bundle (dsh plugin --profile <p> remove dsh-git-bash): every override above disappears with it and the platform gating in @deepseek-ai/dsh-base applies again.

Do not put this swap in a LIVE profile's own cordis.patch.yml instead. That file is watched by patchReload: live, so editing it re-configures running sessions immediately — before this plugin's row is loaded, which leaves them with a shell stack that cannot spawn bash. A bundle patch is read at boot, which is the order this needs.

Install

dsh plugin --profile dsh-tui add file:/absolute/path/to/dsh-git-bash

Then restart the TUI (/restart) and confirm the composition before trusting it:

dsh --profile dsh-tui --dump-config    # composes the tree without starting the UI

Configuration

| Key | Type | Default | Meaning | | --- | --- | --- | --- | | gitBinDir | string | "" | Directory holding bash.exe. Empty = auto-detect. When set, it is the only candidate — a typo is reported instead of being papered over. |

Set it on the plugin's row when detection cannot find your installation:

- id: dsh-git-bash
  config:
    gitBinDir: 'D:\PortableGit\bin'

Known limitations

• This enables a platform-gated stack. dsh disables the bash rows on Windows by design; this plugin removes the reason it cannot work, but that composition is not one upstream tests. Keep the .bak of your cordis.patch.yml: rolling back is deleting the four override lines above.
• Sandbox modes are the untested part. With danger-full-access the executor skips the confinement wrapper entirely, which is what has been exercised here. Under workspace-write the sandbox layer wraps the command in the Windows ACL restricted-token runner — a path built for POSIX. Treat confined modes as unverified.
• A plugin cannot add tools; it can only make the environment the official tools need. If the bash rows are not enabled, this plugin changes nothing visible.
• The PATH edit is process-wide inside the host process, which is exactly the point: every consumer resolving bash (the agent's own commands included) benefits.

Development

pnpm install
pnpm test              # node:test unit tests (pure discovery/PATH rules)
pnpm check:encoding    # no UTF-8 BOM / damaged sequences / tab indentation
pnpm verify            # both, in order

The tests are pure and injectable: resolveBinDir takes its environment and its existence probe as arguments, so the discovery rules are pinned without touching the machine. The win32 cases exercise the real installation when one is present and skip otherwise.

Diagnostics

~/.dsh-tui/dsh-git-bash.log holds one line per decision: the detected directory, already resolvable, PATH left unchanged, the unload restore (or PATH left alone: it changed after this plugin). Every message is also sent to the host logger.

Publishing

• Repository: https://github.com/VviLliAm-qwq/dsh-git-bash (public)
• Release: v* tags drive .github/workflows/release.yml, which publishes to npm through trusted publishing (OIDC) — no token is stored in the repository.

License

MIT.