Add tests for diffing a directory that files were renamed into or out of

Pathspec limiting happens before rename detection in git's tree diff, so
filtering the diff to a directory hides the delete-side entry of a rename
whose other end is outside that directory. Git then has nothing to pair
up, and reports a file moved into the directory as an addition and one
moved out of it as a deletion.

Selecting a directory is supposed to filter the commit's diff down, never
to change it, so both are wrong.

pkg/integration/tests/commit/directory_diff_with_renamed_files.go

@@ -0,0 +1,112 @@
+package commit
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var DirectoryDiffWithRenamedFiles = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Selecting a directory in the commit files panel shows the renames of files that were moved into or out of it",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateDir("dir")
+		shell.CreateDir("dir/nested")
+		shell.CreateFileAndAdd("file1", "file1 content\n")
+		shell.CreateFileAndAdd("dir/file2", "file2 content\n")
+		shell.CreateFileAndAdd("dir/nested/file3", "file3 content\n")
+		shell.Commit("initial commit")
+		shell.RenameFileInGit("file1", "dir/file1")
+		shell.RenameFileInGit("dir/file2", "dir/file2-renamed")
+		shell.RenameFileInGit("dir/nested/file3", "file3")
+		shell.Commit("move files")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Commits().
+			Focus().
+			Lines(
+				Contains("move files").IsSelected(),
+				Contains("initial commit"),
+			).
+			PressEnter()
+
+		t.Views().CommitFiles().
+			IsFocused().
+			Lines(
+				Equals("▼ /").IsSelected(),
+				Equals("  ▼ dir"),
+				Equals("    R file1 → file1"),
+				Equals("    R file2 → file2-renamed"),
+				Equals("  R dir/nested/file3 → file3"),
+			)
+
+		t.Views().Main().ContainsLines(
+			Equals("diff --git a/file1 b/dir/file1"),
+			Equals("similarity index 100%"),
+			Equals("rename from file1"),
+			Equals("rename to dir/file1"),
+			Equals("diff --git a/dir/file2 b/dir/file2-renamed"),
+			Equals("similarity index 100%"),
+			Equals("rename from dir/file2"),
+			Equals("rename to dir/file2-renamed"),
+			Equals("diff --git a/dir/nested/file3 b/file3"),
+			Equals("similarity index 100%"),
+			Equals("rename from dir/nested/file3"),
+			Equals("rename to file3"),
+		)
+
+		t.Views().CommitFiles().
+			SelectNextItem().
+			SelectedLine(Equals("  ▼ dir"))
+
+		t.Views().Main().
+			/* EXPECTED:
+			ContainsLines(
+				Equals("diff --git a/file1 b/dir/file1"),
+				Equals("similarity index 100%"),
+				Equals("rename from file1"),
+				Equals("rename to dir/file1"),
+				Equals("diff --git a/dir/file2 b/dir/file2-renamed"),
+				Equals("similarity index 100%"),
+				Equals("rename from dir/file2"),
+				Equals("rename to dir/file2-renamed"),
+				Equals("diff --git a/dir/nested/file3 b/file3"),
+				Equals("similarity index 100%"),
+				Equals("rename from dir/nested/file3"),
+				Equals("rename to file3"),
+			)
+			ACTUAL: */
+			ContainsLines(
+				Equals("diff --git a/dir/file1 b/dir/file1"),
+				Equals("new file mode 100644"),
+				Contains("index"),
+				Equals("--- /dev/null"),
+				Equals("+++ b/dir/file1"),
+				Equals("@@ -0,0 +1 @@"),
+				Equals("+file1 content"),
+				Equals("diff --git a/dir/file2 b/dir/file2-renamed"),
+				Equals("similarity index 100%"),
+				Equals("rename from dir/file2"),
+				Equals("rename to dir/file2-renamed"),
+				Equals("diff --git a/dir/nested/file3 b/dir/nested/file3"),
+				Equals("deleted file mode 100644"),
+				Contains("index"),
+				Equals("--- a/dir/nested/file3"),
+				Equals("+++ /dev/null"),
+				Equals("@@ -1 +0,0 @@"),
+				Equals("-file3 content"),
+			)
+
+		t.Views().CommitFiles().
+			SelectNextItem().
+			SelectedLine(Equals("    R file1 → file1"))
+
+		t.Views().Main().ContainsLines(
+			Equals("diff --git a/file1 b/dir/file1"),
+			Equals("similarity index 100%"),
+			Equals("rename from file1"),
+			Equals("rename to dir/file1"),
+		)
+	},
+})

pkg/integration/tests/file/directory_diff_with_renamed_files.go

@@ -0,0 +1,119 @@
+package file
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var DirectoryDiffWithRenamedFiles = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Selecting a directory in the files panel shows the renames of files that were moved into or out of it",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateDir("dir")
+		shell.CreateDir("dir/nested")
+		shell.CreateFileAndAdd("file1", "file1 content\n")
+		shell.CreateFileAndAdd("dir/file2", "file2 content\n")
+		shell.CreateFileAndAdd("dir/nested/file3", "file3 content\n")
+		shell.Commit("initial commit")
+		shell.RenameFileInGit("file1", "dir/file1")
+		shell.RenameFileInGit("dir/file2", "dir/file2-renamed")
+		shell.RenameFileInGit("dir/nested/file3", "file3")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			IsFocused().
+			Lines(
+				Equals("▼ /").IsSelected(),
+				Equals("  ▼ dir"),
+				Equals("    R  file1 → file1"),
+				Equals("    R  file2 → file2-renamed"),
+				Equals("  R  dir/nested/file3 → file3"),
+			)
+
+		t.Views().Main().ContainsLines(
+			Equals("diff --git a/file1 b/dir/file1"),
+			Equals("similarity index 100%"),
+			Equals("rename from file1"),
+			Equals("rename to dir/file1"),
+			Equals("diff --git a/dir/file2 b/dir/file2-renamed"),
+			Equals("similarity index 100%"),
+			Equals("rename from dir/file2"),
+			Equals("rename to dir/file2-renamed"),
+			Equals("diff --git a/dir/nested/file3 b/file3"),
+			Equals("similarity index 100%"),
+			Equals("rename from dir/nested/file3"),
+			Equals("rename to file3"),
+		)
+
+		t.Views().Files().
+			SelectNextItem().
+			SelectedLine(Equals("  ▼ dir"))
+
+		t.Views().Main().
+			/* EXPECTED:
+			ContainsLines(
+				Equals("diff --git a/file1 b/dir/file1"),
+				Equals("similarity index 100%"),
+				Equals("rename from file1"),
+				Equals("rename to dir/file1"),
+				Equals("diff --git a/dir/file2 b/dir/file2-renamed"),
+				Equals("similarity index 100%"),
+				Equals("rename from dir/file2"),
+				Equals("rename to dir/file2-renamed"),
+				Equals("diff --git a/dir/nested/file3 b/file3"),
+				Equals("similarity index 100%"),
+				Equals("rename from dir/nested/file3"),
+				Equals("rename to file3"),
+			)
+			ACTUAL: */
+			ContainsLines(
+				Equals("diff --git a/dir/file1 b/dir/file1"),
+				Equals("new file mode 100644"),
+				Contains("index"),
+				Equals("--- /dev/null"),
+				Equals("+++ b/dir/file1"),
+				Equals("@@ -0,0 +1 @@"),
+				Equals("+file1 content"),
+				Equals("diff --git a/dir/file2 b/dir/file2-renamed"),
+				Equals("similarity index 100%"),
+				Equals("rename from dir/file2"),
+				Equals("rename to dir/file2-renamed"),
+				Equals("diff --git a/dir/nested/file3 b/dir/nested/file3"),
+				Equals("deleted file mode 100644"),
+				Contains("index"),
+				Equals("--- a/dir/nested/file3"),
+				Equals("+++ /dev/null"),
+				Equals("@@ -1 +0,0 @@"),
+				Equals("-file3 content"),
+			)
+
+		// The same applies when a filter reduces the directory to a single file
+		t.Views().Files().
+			FilterOrSearch("file1").
+			Lines(
+				Equals("▼ dir").IsSelected(),
+				Equals("  R  file1 → file1"),
+			)
+
+		t.Views().Main().
+			/* EXPECTED:
+			ContainsLines(
+				Equals("diff --git a/file1 b/dir/file1"),
+				Equals("similarity index 100%"),
+				Equals("rename from file1"),
+				Equals("rename to dir/file1"),
+			)
+			ACTUAL: */
+			ContainsLines(
+				Equals("diff --git a/dir/file1 b/dir/file1"),
+				Equals("new file mode 100644"),
+				Contains("index"),
+				Equals("--- /dev/null"),
+				Equals("+++ b/dir/file1"),
+				Equals("@@ -0,0 +1 @@"),
+				Equals("+file1 content"),
+			)
+	},
+})

pkg/integration/tests/test_list.go

@@ -126,6 +126,7 @@ var tests = []*components.IntegrationTest{
 	commit.CreateAmendCommit,
 	commit.CreateFixupCommitInBranchStack,
 	commit.CreateTag,
+	commit.DirectoryDiffWithRenamedFiles,
 	commit.DisableCopyCommitMessageBody,
 	commit.DiscardOldFileChanges,
 	commit.DiscardRenamedFile,
@@ -231,6 +232,7 @@ var tests = []*components.IntegrationTest{
 	file.CollapseExpand,
 	file.CopyMenu,
 	file.DirWithUntrackedFile,
+	file.DirectoryDiffWithRenamedFiles,
 	file.DiscardAllDirChanges,
 	file.DiscardAllDirChangesWhenFiltering,
 	file.DiscardRangeSelect,