Add Windows support

[torryt]

Summary

Riff already builds for Windows via goreleaser and has a sysproc_windows.go build-tagged file, but the binary does not work properly on Windows due to several POSIX assumptions throughout the codebase. This issue tracks everything needed to make riff a fully functional Windows CLI.

Audit Results

Every .go file was evaluated. The codebase breaks down into three categories:

Already cross-platform (no changes needed)

Area	Files	Notes
Entry point / routing	main.go	Pure flag parsing, no OS-specific code
Colors	internal/colors.go	ANSI escapes work on Windows 10+ and Windows Terminal
TTY detection	internal/prompt.go	os.ModeCharDevice works on Windows
Project metadata	internal/projects.go	Uses filepath.Join, os.ReadDir, etc.
File copy / export	cmd/export.go	Uses filepath.Walk, os.Open, etc.
List / clean / config	cmd/list.go, cmd/clean.go, cmd/config.go	stdlib-only file I/O
Update docs	cmd/update_docs.go	No OS-specific code
LLM detection	internal/describe.go	exec.LookPath works cross-platform
Process detach	internal/sysproc_windows.go	Already handled with build tags
Data directory	internal/config.go (InitPaths)	os.UserHomeDir() + filepath.Join — correct on Windows

Needs changes

1. CRITICAL — sh -c for command execution

Files: cmd/new.go:116, cmd/new.go:129

cmd := exec.Command("sh", "-c", tmpl.Command)  // template commands
cmd := exec.Command("sh", "-c", runCmd)         // --run flag

Windows does not have sh. Both template execution and --run are completely broken.

Proposed fix: Create a build-tagged helper in internal/:

// shellcmd_unix.go
//go:build !windows

func ShellCommand(command string) *exec.Cmd {
    return exec.Command("sh", "-c", command)
}

// shellcmd_windows.go
//go:build windows

func ShellCommand(command string) *exec.Cmd {
    return exec.Command("cmd", "/C", command)
}

Then replace both call sites in cmd/new.go with internal.ShellCommand(...).

---

2. CRITICAL — riff init has no PowerShell/cmd support

File: cmd/init.go

The command only emits shell wrappers for bash, zsh, and fish. On Windows the primary shells are PowerShell (pwsh/powershell) and cmd.exe. Without a wrapper, the auto-cd-after-create feature is broken on Windows.

Proposed fix: Add a PowerShell wrapper:

function riff {
    $env:RIFF_WRAPPER = "1"
    & riff.exe @args
    $cdPath = Join-Path $env:USERPROFILE ".riff\.cd-path"
    if (Test-Path $cdPath) {
        $target = Get-Content $cdPath -Raw
        Remove-Item $cdPath
        if ($target -and (Test-Path $target)) {
            Set-Location $target.Trim()
        }
    }
}

And a cmd.exe wrapper (batch):

@echo off
set RIFF_WRAPPER=1
riff.exe %*
set "CD_PATH=%USERPROFILE%\.riff\.cd-path"
if exist "%CD_PATH%" (
    set /p TARGET=<"%CD_PATH%"
    del "%CD_PATH%"
    if defined TARGET cd /d "%TARGET%"
)

Update the switch in RunInit to handle "powershell", "pwsh", and "cmd".

---

3. CRITICAL — DetectShell() returns "" on Windows

File: internal/config.go:100-107

func DetectShell() string {
    shell := filepath.Base(os.Getenv("SHELL"))

Windows does not set the SHELL environment variable. This always returns "" on Windows, which causes EnsureShellWrapper to fall through to a generic message rather than auto-configuring.

Proposed fix: Add Windows-specific detection. Check for:

• PSModulePath env var → PowerShell
• COMSPEC env var → cmd.exe
• Or inspect the parent process name

Example:

func DetectShell() string {
    // Unix: check SHELL
    shell := filepath.Base(os.Getenv("SHELL"))
    switch shell {
    case "bash", "zsh", "fish":
        return shell
    }

    // Windows: check for PowerShell, fall back to cmd
    if runtime.GOOS == "windows" {
        if os.Getenv("PSModulePath") != "" {
            return "powershell"
        }
        return "cmd"
    }

    return ""
}

---

4. CRITICAL — EnsureShellWrapper() only handles Unix config files

File: internal/config.go:111-178

This function writes eval "$(riff init)" to ~/.bashrc, ~/.zshrc, or ~/.config/fish/config.fish. None of these exist on Windows.

Proposed fix: Add cases for PowerShell profile paths:

• $HOME\Documents\PowerShell\Microsoft.PowerShell_profile.ps1 (PowerShell 7+)
• $HOME\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1 (Windows PowerShell 5.x)

The init line for PowerShell would be: . (riff init powershell) or Invoke-Expression (riff init powershell).

For cmd.exe, auto-injection isn't practical (AutoRun registry key is invasive), so print manual instructions instead.

---

5. MODERATE — Hardcoded / path separator in display string

File: internal/config.go:149

relPath := "~/" + strings.TrimPrefix(configFile, home+"/")

On Windows, home uses \ separators, so TrimPrefix with home+"/" will never match and the display path will be wrong.

Proposed fix:

relPath := "~" + string(filepath.Separator) + strings.TrimPrefix(configFile, home+string(filepath.Separator))

---

6. LOW RISK — Git post-commit hook is a POSIX shell script

File: cmd/new.go:145-156

hookContent := fmt.Sprintf("#!/bin/sh\n%s _update-single \"$(git rev-parse --show-toplevel)\" &\n", riffBin)

Git for Windows ships with MSYS2/MinGW and executes hooks through its own sh, so this likely works as-is. However, the & for backgrounding could behave unexpectedly.

Recommendation: Verify this works with Git for Windows. If not, conditionally write a .bat-style hook or use start /b for backgrounding.

---

7. LOW — CI lacks a Windows test runner

File: .github/workflows/ci.yml

CI only runs on ubuntu-latest. There are no Windows-specific tests to catch regressions.

Proposed fix: Add a matrix strategy:

strategy:
  matrix:
    os: [ubuntu-latest, windows-latest]
runs-on: ${{ matrix.os }}

Note: the test report step uses grep and shell constructs that would need adjustment on Windows, or could be skipped via if: runner.os != 'Windows'.

---

Implementation Checklist

• Add internal/shellcmd_unix.go and internal/shellcmd_windows.go (build-tagged shell exec helper)
• Update cmd/new.go to use internal.ShellCommand() instead of exec.Command("sh", "-c", ...)
• Add PowerShell wrapper string to cmd/init.go
• Add cmd.exe wrapper string to cmd/init.go
• Update RunInit switch to handle powershell, pwsh, cmd
• Update DetectShell() to detect PowerShell and cmd.exe on Windows
• Update EnsureShellWrapper() with PowerShell profile path support
• Fix hardcoded / separator in EnsureShellWrapper() display string
• Verify git post-commit hook works with Git for Windows
• Add windows-latest to CI matrix
• Manual smoke test on Windows: riff new, riff new bun, riff new --run "echo hello", riff init powershell, riff list, riff open, riff clean, riff export

Labels

enhancement