dsh-win-multi-bash

A Windows multi-bash plugin for DeepSeek Harness: git_bash / wsl_bash model tools plus a shell-select executor that routes the single ctx.shell seat across Git Bash, WSL and pwsh. Pwsh stays the default, so existing behavior is unchanged until a bash-family tool is called.

What it provides

Tool	Backend	Dialect	Notes
git_bash	git-bash	MSYS	request.shell: 'git-bash', Git for Windows toolchain
wsl_bash	wsl-bash	Linux	request.shell: 'wsl-bash', WSL distro Linux userland
pwsh (existing)	pwsh	—	Selector default route; behavior identical to a deployment without the plugin

• shell-select occupies the single ctx.shell seat and routes request.shell ?? default to one backend; default stays pwsh.
• Executable resolution and sandbox probing are lazy: a host without Git Bash or WSL does not affect pwsh; failures are loud at first use.
• Git Bash is found automatically, in order: an explicit gitBash.bashPath, the well-known Program Files locations, bash.exe on PATH (the Windows WSL launcher System32\bash.exe is never selected — this tool is MSYS, not WSL), Git install roots inferred from git.exe layout directories on PATH (so an install reachable through git is found without a pin), and finally the HKLM\SOFTWARE\GitForWindows install path (which the Git for Windows installer always records, covering custom-drive and portable installs).
• Sandbox auto: Git Bash probes the windows-acl runner, WSL probes bwrap inside the distro; a failed probe degrades honestly to an unconfined run with no sandbox facts. An explicit sandbox: bwrap with bubblewrap missing fails loudly at the first wsl_bash command (never at boot), leaving the other backends untouched.
• All rows register host-plane: every session sees the tools regardless of its agent preset.

Package contents

The full feature implementation ships in lib/ as plain ESM JS — no build step — and imports only dsh's published base packages:

lib/
├── shell-select/   ShellSelectExecutor (the ctx.shell selector)
├── bash-git/       GitBashExecutor (MSYS)
├── bash-wsl/       WslBashExecutor (WSL, base64 payloads)
├── tool-bash/      tool factory + git_bash / wsl_bash instances
└── vendor/         helper modules for runner-failure classification and bwrap profiles

When the deployment's base bundle already provides its own shell-select row, the patch disables that row and lets this plugin's selector own the seat (two providers would conflict). On base bundles without it, the entry is a harmless no-op.

Prerequisites

• A dsh profile with the published @deepseek-ai base packages (every standard deployment).
• Git Bash and/or WSL on the host (a missing backend only errors at first use; pwsh is unaffected).

Plug and unplug

Two mutually exclusive paths insert the same rows. Never use both at once — the loader rejects duplicate entry ids.

Path A: hot plug (recommended, no restart)

# Install
powershell -ExecutionPolicy Bypass -File .\install.ps1            # default profile: web
powershell -ExecutionPolicy Bypass -File .\install.ps1 -ProfileName <name>

# Uninstall
powershell -ExecutionPolicy Bypass -File .\uninstall.ps1

The script links the package into <profile>/node_modules/ (a junction), maintains the package-local node_modules/@deepseek-ai junction the bundled code needs, and writes a managed block into the profile's cordis.patch.yml — dsh web hot-reloads that file, so the feature goes live without a restart. The script is idempotent and auto-detects Git Bash installs outside the default probe paths by reading HKLM:\SOFTWARE\GitForWindows and pinning gitBash.bashPath.

Path B: bundle install (portable, requires restart)

# Install
dsh plugin --profile web add github:@Dinosaur-MC/dsh-win-multi-bash

# Uninstall
dsh plugin --profile web remove dsh-win-multi-bash

Requires pnpm (dsh plugin is a pnpm forwarder); the bundle layer is assembled at boot, so restart dsh web for it to take effect. Works on any profile, including freshly initialized ones.

Verification

powershell -ExecutionPolicy Bypass -File .\smoke\run.ps1

Boots a real composition over the profile runtime (modifying nothing), verifies git_bash / wsl_bash register and execute real commands — including an explicit bashPath variant. Requires node >= 20.

Troubleshooting

Symptom	Fix
New sessions lack git_bash / wsl_bash	Check the managed block exists in the profile patch, the profile node_modules/dsh-win-multi-bash junction exists, and the package-local node_modules/@deepseek-ai junction exists (re-run install.ps1); confirm the running dsh web hot-reloads the profile patch
Boot fails with duplicate loader entry id	Both plug paths are active; remove one of them
Boot fails with Cannot find package '@deepseek-ai/...'	The package-local node_modules/@deepseek-ai junction is missing (re-run install.ps1), or the profile runtime lacks the base packages
git_bash reports bash not found	Git Bash is outside the default probe paths: re-run install.ps1 (registry auto-detect) or set gitBash.bashPath manually
wsl_bash errors	Check wsl.exe --status for a default distro; set wslBash.wslDistro to name one
wsl_bash fails with bwrap was not found	sandbox: bwrap is set but bubblewrap is missing inside the distro: install it (e.g. apt install bubblewrap), or use sandbox: auto / none
wsl_bash sandbox reports a runner failure on bwrap	The bwrap workspace root is the Linux side of a Windows drive path (/mnt/<drive>/...): a UNC workspace root fails loud, and a distro with a custom automount root (wsl.conf automount.root) needs a matching configuration
shell-select: backend "x" is not enabled	The backends list does not match the tool names; keep backends: [git-bash, wsl-bash, pwsh]

Layout

dsh-win-multi-bash/
├── package.json            # dsh.bundle manifest; exports ./shell-select ./tool-git-bash ./tool-wsl-bash
├── cordis.patch.yml        # the composition wiring (documented inline)
├── install.ps1             # Path A hot plug (junctions + managed block + Git Bash detection)
├── uninstall.ps1           # Path A hot unplug
├── LICENSE / THIRD_PARTY_NOTICES
├── lib/                    # bundled implementation (plain ESM JS, no build step)
└── smoke/                  # smoke test (not published)