Bootstrap Git during Windows source installs

install.ps1

@@ -50,6 +50,35 @@ function Ensure-Cargo {
     }
 }
 
+function Ensure-Git {
+    if (Get-Command git -ErrorAction SilentlyContinue) {
+        return
+    }
+    if (-not (Get-Command winget -ErrorAction SilentlyContinue)) {
+        throw "git not found and winget is unavailable; install Git from https://git-scm.com/download/win or set DOSH_USE_PREBUILT=1"
+    }
+    Write-Info "git not found; installing Git with winget"
+    winget install --id Git.Git -e --accept-package-agreements --accept-source-agreements
+    $gitBins = @()
+    if ($env:ProgramFiles) {
+        $gitBins += (Join-Path $env:ProgramFiles "Git\cmd")
+    }
+    if (${env:ProgramFiles(x86)}) {
+        $gitBins += (Join-Path ${env:ProgramFiles(x86)} "Git\cmd")
+    }
+    if ($env:LOCALAPPDATA) {
+        $gitBins += (Join-Path $env:LOCALAPPDATA "Programs\Git\cmd")
+    }
+    foreach ($gitBin in $gitBins) {
+        if ((Test-Path $gitBin) -and -not (PathList-Contains $env:Path $gitBin)) {
+            $env:Path = "$gitBin;$env:Path"
+        }
+    }
+    if (-not (Get-Command git -ErrorAction SilentlyContinue)) {
+        throw "git was installed but is not available in this terminal yet; open a new terminal and rerun dosh update"
+    }
+}
+
 function Normalize-Arch {
     $arch = if ($env:PROCESSOR_ARCHITEW6432) { $env:PROCESSOR_ARCHITEW6432 } else { $env:PROCESSOR_ARCHITECTURE }
     switch ($arch) {
@@ -433,7 +462,7 @@ function Install-FromSource {
         if (-not $Repo) {
             throw "DOSH_REPO is required when running the installer from irm/iex"
         }
-        Require-Command git
+        Ensure-Git
         $sourceCache = Assert-SafeUpdateCache $UpdateCache
         $parent = Split-Path -Parent $sourceCache
         New-Item -ItemType Directory -Force -Path $parent | Out-Null

tests/release_scripts.rs

@@ -219,6 +219,22 @@ fn windows_installer_bootstraps_rust_for_source_fallback_like_unix() {
     assert!(!ps1.contains("Require-Command cargo"));
 }
 
+#[test]
+fn windows_installer_bootstraps_git_for_source_fallback_like_unix() {
+    let ps1 = include_str!("../install.ps1");
+    assert!(ps1.contains("function Ensure-Git"));
+    assert!(ps1.contains("git not found; installing Git with winget"));
+    assert!(ps1.contains("winget install --id Git.Git"));
+    assert!(ps1.contains("--accept-package-agreements --accept-source-agreements"));
+    assert!(ps1.contains("Join-Path $env:ProgramFiles \"Git\\cmd\""));
+    assert!(ps1.contains("Join-Path ${env:ProgramFiles(x86)} \"Git\\cmd\""));
+    assert!(ps1.contains("Join-Path $env:LOCALAPPDATA \"Programs\\Git\\cmd\""));
+    assert!(ps1.contains("PathList-Contains $env:Path $gitBin"));
+    assert!(ps1.contains("$env:Path = \"$gitBin;$env:Path\""));
+    assert!(ps1.contains("Ensure-Git"));
+    assert!(!ps1.contains("Require-Command git"));
+}
+
 #[test]
 fn windows_installer_honors_quiet_update_mode() {
     let ps1 = include_str!("../install.ps1");