Show the window before slow location probes and wrap git.exe for commit, diff, and merge.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/Explorer.Application.Tests/GitDiffParserTests.cs

@@ -0,0 +1,86 @@
+using Explorer.Application;
+using Explorer.Domain;
+
+namespace Explorer.Application.Tests;
+
+public class GitDiffPlannerTests
+{
+    [Fact]
+    public void Staged_diff_does_not_read_the_working_tree()
+    {
+        var request = GitDiffPlanner.Create(new GitChange
+        {
+            Path = "src/App.cs",
+            State = GitChangeState.Staged,
+            Index = 'M',
+            WorkTree = '.'
+        });
+        Assert.Null(request.Error);
+        Assert.False(request.NeedsWorkingTree);
+        Assert.Contains("--cached", request.Arguments);
+        Assert.Contains("src/App.cs", request.Arguments);
+    }
+
+    [Fact]
+    public void Untracked_diff_uses_no_index_against_dev_null()
+    {
+        var request = GitDiffPlanner.Create(new GitChange
+        {
+            Path = "new.txt",
+            State = GitChangeState.Untracked,
+            Index = '?',
+            WorkTree = '?'
+        });
+        Assert.True(request.NeedsWorkingTree);
+        Assert.Contains("--no-index", request.Arguments);
+        Assert.Contains("/dev/null", request.Arguments);
+        Assert.Contains("new.txt", request.Arguments);
+    }
+
+    [Fact]
+    public void Deleted_unstaged_diff_does_not_need_the_working_tree()
+    {
+        var request = GitDiffPlanner.Create(new GitChange
+        {
+            Path = "gone.cs",
+            State = GitChangeState.Unstaged,
+            Index = '.',
+            WorkTree = 'D'
+        });
+        Assert.False(request.NeedsWorkingTree);
+        Assert.DoesNotContain("--cached", request.Arguments);
+    }
+}
+
+public class GitDiffParserTests
+{
+    [Fact]
+    public void Classifies_unified_diff_lines()
+    {
+        var diff = GitDiffParser.Parse("""
+            diff --git a/src/App.cs b/src/App.cs
+            index 111..222 100644
+            --- a/src/App.cs
+            +++ b/src/App.cs
+            @@ -1,3 +1,4 @@
+             keep
+            -old
+            +new
+             still
+            """, "src/App.cs");
+        Assert.Equal("src/App.cs", diff.Title);
+        Assert.False(diff.IsBinary);
+        Assert.Equal(GitDiffLineKind.Meta, diff.Lines[0].Kind);
+        Assert.Equal(GitDiffLineKind.Hunk, diff.Lines[4].Kind);
+        Assert.Equal(GitDiffLineKind.Context, diff.Lines[5].Kind);
+        Assert.Equal(GitDiffLineKind.Removed, diff.Lines[6].Kind);
+        Assert.Equal(GitDiffLineKind.Added, diff.Lines[7].Kind);
+    }
+
+    [Fact]
+    public void Marks_binary_and_empty()
+    {
+        Assert.True(GitDiffParser.Parse("Binary files a/x and b/x differ\n", "x").IsBinary);
+        Assert.True(GitDiffParser.Parse("", "x").IsEmpty);
+    }
+}