Introduce records to keep track of git change data, and leverage them to make clearer reporting.

Author: cotti

src/tooling/docs-builder/Cli/DiffCommands.cs

@@ -32,7 +32,7 @@ public async Task<int> ValidateRedirects([Argument] string? path = null, Cancel
 		ConsoleApp.Log = msg => log.LogInformation(msg);
 		ConsoleApp.LogError = msg => log.LogError(msg);
 
-		path ??= "docs";
+		path ??= "";
 
 		await using var collector = new ConsoleDiagnosticsCollector(logger, githubActionsService).StartAsync(ctx);
 
@@ -57,8 +57,20 @@ public async Task<int> ValidateRedirects([Argument] string? path = null, Cancel
 		var tracker = new LocalGitRepositoryTracker(collector, root);
 		var changed = tracker.GetChangedFiles(path);
 
-		foreach (var notFound in changed.Where(c => !redirects.ContainsKey(c)))
-			collector.EmitError(notFound, $"{notFound} does not have a redirect rule set. Please add a redirect rule in this project's {redirectFileInfo.Name}.");
+		foreach (var notFound in changed.Where(c => c.ChangeType is GitChangeType.Deleted or GitChangeType.Renamed
+																	&& !redirects.ContainsKey(c is RenamedGitChange renamed ? renamed.OldFilePath : c.FilePath)))
+		{
+			if (notFound is RenamedGitChange renamed)
+			{
+				collector.EmitError(redirectFileInfo.Name,
+					$"File '{renamed.OldFilePath}' was renamed to '{renamed.NewFilePath}' but it has no redirect configuration set.");
+			}
+			else if (notFound.ChangeType is GitChangeType.Deleted)
+			{
+				collector.EmitError(redirectFileInfo.Name,
+					$"File '{notFound.FilePath}' was deleted but it has no redirect targets. This will lead to broken links.");
+			}
+		}
 
 		await collector.StopAsync(ctx);
 		return collector.Errors;

src/tooling/docs-builder/Tracking/IRepositoryTracker.cs

@@ -4,7 +4,17 @@
 
 namespace Documentation.Builder.Tracking;
 
+public enum GitChangeType
+{
+	Added,
+	Modified,
+	Deleted,
+	Renamed,
+	Untracked,
+	Other
+}
+
 public interface IRepositoryTracker
 {
-	IEnumerable<string> GetChangedFiles(string lookupPath);
+	IEnumerable<GitChange> GetChangedFiles(string lookupPath);
 }

src/tooling/docs-builder/Tracking/LocalGitRepositoryTracker.cs

@@ -5,25 +5,21 @@
 using System.IO.Abstractions;
 using Elastic.Documentation.Diagnostics;
 using Elastic.Documentation.Tooling.ExternalCommands;
+
 namespace Documentation.Builder.Tracking;
 
-public partial class LocalGitRepositoryTracker(DiagnosticsCollector collector, IDirectoryInfo workingDirectory) : ExternalCommandExecutor(collector, workingDirectory), IRepositoryTracker
+public record GitChange(string FilePath, GitChangeType ChangeType);
+public record RenamedGitChange(string OldFilePath, string NewFilePath, GitChangeType ChangeType) : GitChange(OldFilePath, ChangeType);
+
+public class LocalGitRepositoryTracker(DiagnosticsCollector collector, IDirectoryInfo workingDirectory) : ExternalCommandExecutor(collector, workingDirectory), IRepositoryTracker
 {
-	public IEnumerable<string> GetChangedFiles(string lookupPath)
+	public IEnumerable<GitChange> GetChangedFiles(string lookupPath)
 	{
 		var defaultBranch = GetDefaultBranch();
 		var commitChanges = CaptureMultiple("git", "diff", "--name-status", $"{defaultBranch}...HEAD", "--", $"./{lookupPath}");
 		var localChanges = CaptureMultiple("git", "status", "--porcelain");
-		List<string> output = [
-			.. commitChanges
-			.Where(line => line.StartsWith('R') || line.StartsWith('D') || line.StartsWith('A'))
-			.Select(line => line.Split('\t')[1]),
-			.. localChanges
-			.Select(x => x.TrimStart())
-			.Where(line => line.StartsWith('R') || line.StartsWith('D') || line.StartsWith("A ", StringComparison.Ordinal) || line.StartsWith("??"))
-			.Select(line => line.Split(' ', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)[1])
-		];
-		return output.Where(line => line.StartsWith(lookupPath));
+
+		return [.. GetCommitChanges(commitChanges), .. GetLocalChanges(localChanges)];
 	}
 
 	private string GetDefaultBranch()
@@ -34,4 +30,53 @@ private string GetDefaultBranch()
 			return "master";
 		return Capture("git", "symbolic-ref", "refs/remotes/origin/HEAD").Split('/').Last();
 	}
+
+	private static IEnumerable<GitChange> GetCommitChanges(string[] changes)
+	{
+		foreach (var change in changes)
+		{
+			var parts = change.AsSpan().TrimStart();
+			if (parts.Length < 2)
+				continue;
+
+			var changeType = parts[0] switch
+			{
+				'A' => GitChangeType.Added,
+				'M' => GitChangeType.Modified,
+				'D' => GitChangeType.Deleted,
+				'R' => GitChangeType.Renamed,
+				_ => GitChangeType.Other
+			};
+
+			yield return new GitChange(change.Split('\t')[1], changeType);
+		}
+	}
+
+	private static IEnumerable<GitChange> GetLocalChanges(string[] changes)
+	{
+		foreach (var change in changes)
+		{
+			var changeStatusCode = change.AsSpan();
+			if (changeStatusCode.Length < 2)
+				continue;
+
+			var changeType = (changeStatusCode[0], changeStatusCode[1]) switch
+			{
+				('R', _) or (_, 'R') => GitChangeType.Renamed,
+				('D', _) or (_, 'D') when changeStatusCode[0] != 'A' => GitChangeType.Deleted,
+				('?', '?') => GitChangeType.Untracked,
+				('A', _) or (_, 'A') => GitChangeType.Added,
+				('M', _) or (_, 'M') => GitChangeType.Modified,
+				_ => GitChangeType.Other
+			};
+
+			var changeParts = change.Split(' ', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+
+			yield return changeType switch
+			{
+				GitChangeType.Renamed => new RenamedGitChange(changeParts[1], changeParts[3], changeType),
+				_ => new GitChange(changeParts[1], changeType)
+			};
+		}
+	}
 }