Add a script to diff the contents of folders that match a specific pattern across two branches

scripts/DiffBranches.ps1

@@ -0,0 +1,101 @@
+<#
+.SYNOPSIS
+    A script to diff the contents of folders matching a specified pattern between two specified branches.
+
+.DESCRIPTION
+    The script uses git to determine the set of files (under folders matching a specified pattern) that are different
+    between the specified branches. It can also optionally display the line diffs for these files.
+
+.PARAMETER baseline
+    The baseline branch against which the specified target branch is to be compared. (Defaults to 'main' if omitted.)
+.PARAMETER target
+    The target branch which is to be compared against the specified baseline branch.
+.PARAMETER folderPattern
+    The pattern that selects the folders that are to be compared. (Defaults to '*.AI.* if omitted.)
+.PARAMETER showDiff
+    Determines whether or not line diffs should be displayed for the differing files. (Defaults to 'false' if omitted.)
+
+.EXAMPLE
+    PS> .\DiffBranches -target "release/9.5" -folderPattern "*.Evaluation.*"
+.EXAMPLE
+    PS> .\DiffBranches -baseline "release/9.4" -target "release/9.5" -folderPattern "*.Evaluation.*"
+.EXAMPLE
+    PS> .\DiffBranches -target "release/9.5" -showDiff
+#>
+
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory=$false)]
+    [string]$baseline = "main",
+
+    [Parameter(Mandatory=$true)]
+    [string]$target,
+
+    [Parameter(Mandatory=$false)]
+    [string]$folderPattern = "*.AI.*",
+
+    [Parameter(Mandatory=$false)]
+    [switch]$showDiff
+)
+
+function Invoke-GitCommand {
+    param(
+        [Parameter(Mandatory=$true)]
+        [string]$Command,
+
+        [Parameter(Mandatory=$false)]
+        [switch]$UseCmd
+    )
+
+    if ($UseCmd) {
+        $Command = "cmd.exe /c $Command"
+    }
+
+    Write-Host "Executing $Command" -ForegroundColor Blue
+    $result = Invoke-Expression $Command
+    return $result
+}
+
+# Save the current directory
+$originalLocation = Get-Location
+
+try {
+    # Get the root directory of the git repository
+    $gitRootCommand = "git rev-parse --show-toplevel"
+    $repoRoot = Invoke-GitCommand -Command $gitRootCommand
+    Write-Host "Repo root is $repoRoot" -ForegroundColor Blue
+
+    # Change to the repository root directory
+    Set-Location $repoRoot
+
+    # Get all changed files between the two branches
+    $gitFilesCommand = "git diff --name-only $baseline..$target"
+    $changedFiles = Invoke-GitCommand -Command $gitFilesCommand
+
+    # Filter for files under folders containing the specified pattern
+    $matchedFiles = $changedFiles | Where-Object { 
+        $path = $_
+        $folders = $path -split '/'
+        $folders | Where-Object { $_ -like $folderPattern } | Select-Object -First 1
+    }
+
+    if ($matchedFiles.Count -eq 0) {
+        Write-Host "No changes detected." -ForegroundColor Green
+    } else {
+        Write-Host "Changes detected in following files:" -ForegroundColor Yellow
+        $matchedFiles | ForEach-Object { Write-Host "  $_" }
+
+        if ($showDiff) {
+            Write-Host "File diffs:" -ForegroundColor Yellow
+
+            $gitDiffCommand = "git -C `"$repoRoot`" diff --color $baseline..$target -- $($matchedFiles -join ' ')"
+
+            # Use the -UseCmd switch to run the command with cmd.exe (preserves color and paging)
+            Invoke-GitCommand -Command $gitDiffCommand -UseCmd
+        }
+    }
+}
+finally {
+    # Return to the original directory even if an error occurs
+    Set-Location $originalLocation
+}