Report branch and tag names unprefixed when a branch and tag share a name [patch]

GitIntegration.Test/Builders/GitBranchListBuilderTests.cs

@@ -8,7 +8,7 @@ namespace ktsu.GitIntegration.Test;
 public class GitBranchListBuilderTests
 {
 	private const string ExpectedFormat =
-		"--format=%(refname)%1f%(refname:short)%1f%(objectname)%1f%(upstream:short)%1f%(HEAD)";
+		"--format=%(refname)%1f%(refname:lstrip=2)%1f%(objectname)%1f%(upstream:lstrip=2)%1f%(HEAD)";
 
 	[TestMethod]
 	public void BuildsTheDefaultBranchListVector()

GitIntegration.Test/Integration/GitRoundTripTests.cs

@@ -382,6 +382,81 @@
 		Assert.AreEqual(annotated, afterDelete[0].Name);
 	}
 
+	[TestMethod]
+	public async Task BranchAndTagSharingANameAreBothReportedByThatNameAsync()
+	{
+		// A release branch and a release tag both called v1 make the short name ambiguous, and
+		// %(refname:short) then keeps part of the prefix: heads/v1 and tags/v1, which git itself
+		// refuses when they are passed back.
+		CancellationToken cancellationToken = TestContext.CancellationTokenSource.Token;
+		await IntegrationGitFixture.RequireGitAsync(cancellationToken).ConfigureAwait(false);
+
+		using TemporaryRepository temporary = new();
+		GitRepository repository = await InitializeAsync(temporary, cancellationToken).ConfigureAwait(false);
+
+		temporary.WriteFile("a.txt", "one\n");
+		_ = await repository.Add().All().ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		_ = await repository.Commit("c1".As<GitCommitMessage>()).ExecuteAsync(cancellationToken).ConfigureAwait(false);
+
+		_ = await repository.CreateBranch("v1".As<GitBranchName>()).ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		_ = await repository.CreateTag("v1".As<GitTagName>()).ExecuteAsync(cancellationToken).ConfigureAwait(false);
+
+		IReadOnlyList<GitBranch> branches =
+			await repository.Branches().LocalOnly().ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		Assert.AreEqual(2, branches.Count);
+		Assert.IsTrue(branches.Any(static branch => branch.Name.WeakString == "main"));
+		Assert.IsTrue(branches.Any(static branch => branch.Name.WeakString == "v1"));
+
+		IReadOnlyList<GitTag> tags = await repository.Tags().ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		Assert.AreEqual("v1", tags.Single().Name.WeakString);
+
+		// The reported names are usable: deleting by them succeeds.
+		_ = await repository.DeleteBranch(branches.Single(static branch => branch.Name.WeakString == "v1").Name)
+			.ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		_ = await repository.DeleteTag(tags.Single().Name).ExecuteAsync(cancellationToken).ConfigureAwait(false);
+	}
+
+	[TestMethod]
+	public async Task LocalBranchNamedLikeARemoteBranchLeavesTheRemoteNameAndUpstreamIntactAsync()
+	{
+		// A local branch called origin/main makes refs/remotes/origin/main shorten to
+		// remotes/origin/main, which used to leak into both the remote branch's name and the
+		// upstream of every branch tracking it.
+		CancellationToken cancellationToken = TestContext.CancellationTokenSource.Token;
+		await IntegrationGitFixture.RequireGitAsync(cancellationToken).ConfigureAwait(false);
+
+		using TemporaryRepository temporary = new();
+		GitRepository repository = await InitializeAsync(temporary, cancellationToken).ConfigureAwait(false);
+
+		temporary.WriteFile("a.txt", "one\n");
+		_ = await repository.Add().All().ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		_ = await repository.Commit("c1".As<GitCommitMessage>()).ExecuteAsync(cancellationToken).ConfigureAwait(false);
+
+		// The remote is never contacted; git only needs its fetch refspec to resolve the upstream.
+		IGitProcessRunner runner = repository.ProcessRunner!;
+		_ = await new GitTextBuilder(runner, repository.LocalPath, "remote", "add", "origin", "https://example.invalid/r.git")
+			.ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		_ = await new GitTextBuilder(runner, repository.LocalPath, "update-ref", "refs/remotes/origin/main", "HEAD")
+			.ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		_ = await new GitTextBuilder(runner, repository.LocalPath, "config", "branch.main.remote", "origin")
+			.ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		_ = await new GitTextBuilder(runner, repository.LocalPath, "config", "branch.main.merge", "refs/heads/main")
+			.ExecuteAsync(cancellationToken).ConfigureAwait(false);
+		_ = await repository.CreateBranch("origin/main".As<GitBranchName>()).ExecuteAsync(cancellationToken).ConfigureAwait(false);
+
+		IReadOnlyList<GitBranch> branches =
+			await repository.Branches().ExecuteAsync(cancellationToken).ConfigureAwait(false);
+
+		GitBranch remote = branches.Single(static branch => branch.IsRemote);
+		Assert.AreEqual("origin/main", remote.Name.WeakString);
+
+		GitBranch local = branches.Single(static branch => !branch.IsRemote && branch.Name.WeakString == "origin/main");
+		Assert.IsFalse(local.IsCurrent);
+
+		GitBranch main = branches.Single(static branch => branch.Name.WeakString == "main");
+		Assert.AreEqual("origin/main", main.Upstream?.WeakString);
+	}
+
 	[TestMethod]
 	public async Task CheckoutResolvesATagRatherThanAFileOfTheSameNameAsync()
 	{

GitIntegration/Parsing/GitBranchParser.cs

@@ -62,7 +62,7 @@ internal static IReadOnlyList<GitBranch> Parse(string output)
 				Name = GitParseValues.ToSemantic<GitBranchName>(fields[1], "branch name"),
 				Sha = GitParseValues.ToSemantic<GitCommitSha>(fields[2], "branch object id"),
 
-				// %(upstream:short) is empty when the branch tracks nothing.
+				// %(upstream:lstrip=2) is empty when the branch tracks nothing.
 				Upstream = fields[3].Length == 0
 					? null
 					: GitParseValues.ToSemantic<GitBranchName>(fields[3], "upstream branch name"),

GitIntegration/Parsing/GitOutputFormats.cs

@@ -35,8 +35,8 @@ internal static class GitOutputFormats
 	internal const string LogFormat = "%H%x1f%T%x1f%P%x1f%an%x1f%ae%x1f%aI%x1f%cn%x1f%ce%x1f%cI%x1f%s%x1f%b";
 
 	/// <summary>
-	/// The <c>for-each-ref</c> format: full reference name, short name, object id, upstream, and
-	/// the current-branch marker.
+	/// The <c>for-each-ref</c> format: full reference name, name, object id, upstream, and the
+	/// current-branch marker.
 	/// </summary>
 	/// <remarks>
 	/// The full reference name leads, and is the reason this format differs from the one sketched
@@ -46,12 +46,19 @@ internal static class GitOutputFormats
 	/// and would otherwise be reported as a branch called <c>origin</c>. <c>%1f</c> is
 	/// <c>for-each-ref</c>'s own hex escape, which differs in spelling from <c>log</c>'s
 	/// <c>%x1f</c> but means the same byte.
+	/// <para>
+	/// Names come from <c>:lstrip=2</c>, never <c>:short</c>. <c>:short</c> keeps part of the prefix
+	/// whenever the shortest name would be ambiguous, so a branch and a tag both called <c>v1</c>
+	/// come back as <c>heads/v1</c> and <c>tags/v1</c>, names git itself then refuses. Stripping
+	/// <c>refs/heads/</c>, <c>refs/remotes/</c> or <c>refs/tags/</c> outright always yields the name
+	/// the reference was created with.
+	/// </para>
 	/// </remarks>
 	internal const string ForEachRefFormat =
-		"%(refname)%1f%(refname:short)%1f%(objectname)%1f%(upstream:short)%1f%(HEAD)";
+		"%(refname)%1f%(refname:lstrip=2)%1f%(objectname)%1f%(upstream:lstrip=2)%1f%(HEAD)";
 
 	/// <summary>
-	/// The <c>for-each-ref</c> format for tags: short name, the reference's own object id, the
+	/// The <c>for-each-ref</c> format for tags: name, the reference's own object id, the
 	/// object type, the dereferenced object id, and the message subject.
 	/// </summary>
 	/// <remarks>
@@ -76,7 +83,11 @@ internal static class GitOutputFormats
 	/// tagger's words. <see cref="GitTagParser"/> gates it on the object type for that reason.
 	/// Verified against git 2.43.
 	/// </para>
+	/// <para>
+	/// The name is <c>:lstrip=2</c> rather than <c>:short</c> for the reason
+	/// <see cref="ForEachRefFormat"/> gives.
+	/// </para>
 	/// </remarks>
 	internal const string ForEachTagFormat =
-		"%(refname:short)%1f%(objectname)%1f%(objecttype)%1f%(*objectname)%1f%(contents:subject)";
+		"%(refname:lstrip=2)%1f%(objectname)%1f%(objecttype)%1f%(*objectname)%1f%(contents:subject)";
 }