fix: match .git as complete path component, not suffix

Searching for `.git/` in file paths incorrectly matched directory names
ending with `.git` (e.g., `personal.git/cheat/hello`), causing sheets
under such paths to be silently skipped. Fix by requiring the path
separator on both sides (`/.git/`), so `.git` is only matched as a
complete path component.

Rewrites test suite with comprehensive coverage for all six documented
edge cases, including the #711 scenario and combination cases (e.g.,
a real .git directory inside a .git-suffixed parent).

Closes #711

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/repo/gitdir.go

@@ -6,6 +6,11 @@ import (
 	"strings"
 )
 
+// gitSep is the `.git` path component surrounded by path separators.
+// Used to match `.git` as a complete path component, not as a suffix
+// of a directory name (e.g., `personal.git`).
+var gitSep = string(os.PathSeparator) + ".git" + string(os.PathSeparator)
+
 // GitDir returns `true` if we are iterating over a directory contained within
 // a repositories `.git` directory.
 func GitDir(path string) (bool, error) {
@@ -50,9 +55,20 @@ func GitDir(path string) (bool, error) {
 
 		See: https://github.com/cheat/cheat/issues/699
 
-		Accounting for all of the above (hopefully?), the current solution is
-		not to search for `.git`, but `.git/` (including the directory
-		separator), and then only ceasing to walk the directory on a match.
+		Accounting for all of the above, the next solution was to search not
+		for `.git`, but `.git/` (including the directory separator), and then
+		only ceasing to walk the directory on a match.
+
+		This, however, also had a bug: searching for `.git/` also matched
+		directory names that *ended with* `.git`, like `personal.git/`. This
+		caused cheatsheets stored under such paths to be silently skipped.
+
+		See: https://github.com/cheat/cheat/issues/711
+
+		The current (and hopefully final) solution requires the path separator
+		on *both* sides of `.git`, i.e., searching for `/.git/`. This ensures
+		that `.git` is matched only as a complete path component, not as a
+		suffix of a directory name.
 
 		To summarize, this code must account for the following possibilities:
 
@@ -61,17 +77,16 @@ func GitDir(path string) (bool, error) {
 		3. A cheatpath is a repository, and contains a `.git*` file
 		4. A cheatpath is a submodule
 		5. A cheatpath is a hidden directory
+		6. A cheatpath is inside a directory whose name ends with `.git`
 
 		Care must be taken to support the above on both Unix and Windows
 		systems, which have different directory separators and line-endings.
 
-		There is a lot of nuance to all of this, and it would be worthwhile to
-		do two things to stop writing bugs here:
+		NB: `filepath.Walk` always passes absolute paths to the walk function,
+		so `.git` will never appear as the first path component. This is what
+		makes the "separator on both sides" approach safe.
 
-		1. Build integration tests around all of this
-		2. Discard string-matching solutions entirely, and use `go-git` instead
-
-		NB: A reasonable smoke-test for ensuring that skipping is being applied
+		A reasonable smoke-test for ensuring that skipping is being applied
 		correctly is to run the following command:
 
 		    make && strace ./dist/cheat -l | wc -l
@@ -83,8 +98,8 @@ func GitDir(path string) (bool, error) {
 		of syscalls should be significantly lower with the skip check enabled.
 	*/
 
-	// determine if the literal string `.git` appears within `path`
-	pos := strings.Index(path, fmt.Sprintf(".git%s", string(os.PathSeparator)))
+	// determine if `.git` appears as a complete path component
+	pos := strings.Index(path, gitSep)
 
 	// if it does not, we know for certain that we are not within a `.git`
 	// directory.

internal/repo/gitdir_test.go

@@ -1,137 +1,191 @@
 package repo
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
 )
 
-func TestGitDir(t *testing.T) {
-	// Create a temporary directory for testing
-	tempDir, err := os.MkdirTemp("", "cheat-test-*")
-	if err != nil {
-		t.Fatalf("failed to create temp dir: %v", err)
-	}
-	defer os.RemoveAll(tempDir)
+// setupGitDirTestTree creates a temporary directory structure that exercises
+// every case documented in GitDir's comment block. The caller must defer
+// os.RemoveAll on the returned root.
+//
+// Layout:
+//
+//	root/
+//	├── plain/                         # not a repository
+//	│   └── sheet
+//	├── repo/                          # a repository (.git is a directory)
+//	│   ├── .git/
+//	│   │   ├── HEAD
+//	│   │   ├── objects/
+//	│   │   │   └── pack/
+//	│   │   └── refs/
+//	│   │       └── heads/
+//	│   ├── .gitignore
+//	│   ├── .gitattributes
+//	│   └── sheet
+//	├── submodule/                     # a submodule (.git is a file)
+//	│   ├── .git                       # file, not directory
+//	│   └── sheet
+//	├── dotgit-suffix.git/             # directory name ends in .git (#711)
+//	│   └── cheat/
+//	│       └── sheet
+//	├── dotgit-mid.git/                # .git suffix mid-path (#711)
+//	│   └── nested/
+//	│       └── sheet
+//	├── .github/                       # .github directory (not .git)
+//	│   └── workflows/
+//	│       └── ci.yml
+//	└── .hidden/                       # generic hidden directory
+//	    └── sheet
+func setupGitDirTestTree(t *testing.T) string {
+	t.Helper()
 
-	// Create test directory structure
-	testDirs := []string{
-		filepath.Join(tempDir, ".git"),
-		filepath.Join(tempDir, ".git", "objects"),
-		filepath.Join(tempDir, ".git", "refs"),
-		filepath.Join(tempDir, "regular"),
-		filepath.Join(tempDir, "regular", ".git"),
-		filepath.Join(tempDir, "submodule"),
+	root := t.TempDir()
+
+	dirs := []string{
+		// case 1: not a repository
+		filepath.Join(root, "plain"),
+
+		// case 2: a repository (.git directory with contents)
+		filepath.Join(root, "repo", ".git", "objects", "pack"),
+		filepath.Join(root, "repo", ".git", "refs", "heads"),
+
+		// case 4: a submodule (.git is a file)
+		filepath.Join(root, "submodule"),
+
+		// case 6: directory name ending in .git (#711)
+		filepath.Join(root, "dotgit-suffix.git", "cheat"),
+		filepath.Join(root, "dotgit-mid.git", "nested"),
+
+		// .github (should not be confused with .git)
+		filepath.Join(root, ".github", "workflows"),
+
+		// generic hidden directory
+		filepath.Join(root, ".hidden"),
 	}
 
-	for _, dir := range testDirs {
+	for _, dir := range dirs {
 		if err := os.MkdirAll(dir, 0755); err != nil {
 			t.Fatalf("failed to create dir %s: %v", dir, err)
 		}
 	}
 
-	// Create test files
-	testFiles := map[string]string{
-		filepath.Join(tempDir, ".gitignore"):           "*.tmp\n",
-		filepath.Join(tempDir, ".gitattributes"):       "* text=auto\n",
-		filepath.Join(tempDir, "submodule", ".git"):    "gitdir: ../.git/modules/submodule\n",
-		filepath.Join(tempDir, "regular", "sheet.txt"): "content\n",
+	files := map[string]string{
+		// sheets
+		filepath.Join(root, "plain", "sheet"):                      "plain sheet",
+		filepath.Join(root, "repo", "sheet"):                       "repo sheet",
+		filepath.Join(root, "submodule", "sheet"):                  "submod sheet",
+		filepath.Join(root, "dotgit-suffix.git", "cheat", "sheet"): "dotgit sheet",
+		filepath.Join(root, "dotgit-mid.git", "nested", "sheet"):   "dotgit nested",
+		filepath.Join(root, ".hidden", "sheet"):                    "hidden sheet",
+
+		// git metadata
+		filepath.Join(root, "repo", ".git", "HEAD"):           "ref: refs/heads/main\n",
+		filepath.Join(root, "repo", ".gitignore"):             "*.tmp\n",
+		filepath.Join(root, "repo", ".gitattributes"):         "* text=auto\n",
+		filepath.Join(root, "submodule", ".git"):              "gitdir: ../.git/modules/sub\n",
+		filepath.Join(root, ".github", "workflows", "ci.yml"): "name: CI\n",
 	}
 
-	for file, content := range testFiles {
-		if err := os.WriteFile(file, []byte(content), 0644); err != nil {
-			t.Fatalf("failed to create file %s: %v", file, err)
+	for path, content := range files {
+		if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+			t.Fatalf("failed to write %s: %v", path, err)
 		}
 	}
 
+	return root
+}
+
+func TestGitDir(t *testing.T) {
+	root := setupGitDirTestTree(t)
+
 	tests := []struct {
 		name string
 		path string
 		want bool
-		wantErr bool
 	}{
+		// Case 1: not a repository — no .git anywhere in path
 		{
-			name: "not in git directory",
-			path: filepath.Join(tempDir, "regular", "sheet.txt"),
+			name: "plain directory, no repo",
+			path: filepath.Join(root, "plain", "sheet"),
 			want: false,
 		},
+
+		// Case 2: a repository — paths *inside* .git/ should be detected
 		{
-			name: "in .git directory",
-			path: filepath.Join(tempDir, ".git", "objects", "file"),
+			name: "inside .git directory",
+			path: filepath.Join(root, "repo", ".git", "HEAD"),
 			want: true,
 		},
 		{
-			name: "in .git/refs directory",
-			path: filepath.Join(tempDir, ".git", "refs", "heads", "main"),
+			name: "inside .git/objects",
+			path: filepath.Join(root, "repo", ".git", "objects", "pack", "somefile"),
 			want: true,
 		},
+		{
+			name: "inside .git/refs",
+			path: filepath.Join(root, "repo", ".git", "refs", "heads", "main"),
+			want: true,
+		},
+
+		// Case 2 (cont.): files *alongside* .git should NOT be detected
+		{
+			name: "sheet in repo root (beside .git dir)",
+			path: filepath.Join(root, "repo", "sheet"),
+			want: false,
+		},
+
+		// Case 3: .git* files (like .gitignore) should NOT trigger
 		{
 			name: ".gitignore file",
-			path: filepath.Join(tempDir, ".gitignore"),
+			path: filepath.Join(root, "repo", ".gitignore"),
 			want: false,
 		},
 		{
 			name: ".gitattributes file",
-			path: filepath.Join(tempDir, ".gitattributes"),
+			path: filepath.Join(root, "repo", ".gitattributes"),
 			want: false,
 		},
-		{
-			name: "submodule with .git file",
-			path: filepath.Join(tempDir, "submodule", "sheet.txt"),
-			want: false,
-		},
-		{
-			name: "path with .git in middle",
-			path: filepath.Join(tempDir, "regular", ".git", "sheet.txt"),
-			want: true,
-		},
-		{
-			name: "nonexistent path without .git",
-			path: filepath.Join(tempDir, "nonexistent", "file"),
-			want: false,
-		},
-	}
 
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, err := GitDir(tt.path)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("GitDir() error = %v, wantErr %v", err, tt.wantErr)
-				return
-			}
-			if got != tt.want {
-				t.Errorf("GitDir() = %v, want %v", got, tt.want)
-			}
-		})
-	}
-}
+		// Case 4: submodule — .git is a file, not a directory
+		{
+			name: "sheet in submodule (where .git is a file)",
+			path: filepath.Join(root, "submodule", "sheet"),
+			want: false,
+		},
 
-func TestGitDirEdgeCases(t *testing.T) {
-	// Test with paths that have .git but not as a directory separator
-	tests := []struct {
-		name string
-		path string
-		want bool
-	}{
+		// Case 6: directory name ends with .git (#711)
 		{
-			name: "file ending with .git",
-			path: "/tmp/myfile.git",
+			name: "sheet under directory ending in .git",
+			path: filepath.Join(root, "dotgit-suffix.git", "cheat", "sheet"),
 			want: false,
 		},
 		{
-			name: "directory ending with .git",
-			path: "/tmp/myrepo.git",
+			name: "sheet under .git-suffixed dir, nested deeper",
+			path: filepath.Join(root, "dotgit-mid.git", "nested", "sheet"),
 			want: false,
 		},
+
+		// .github directory — must not be confused with .git
 		{
-			name: ".github directory",
-			path: "/tmp/.github/workflows",
+			name: "file inside .github directory",
+			path: filepath.Join(root, ".github", "workflows", "ci.yml"),
 			want: false,
 		},
+
+		// Hidden directory that is not .git
 		{
-			name: "legitimate.git-repo name",
-			path: "/tmp/legitimate.git-repo/file",
+			name: "file inside generic hidden directory",
+			path: filepath.Join(root, ".hidden", "sheet"),
+			want: false,
+		},
+
+		// Path with no .git at all
+		{
+			name: "path with no .git component whatsoever",
+			path: filepath.Join(root, "nonexistent", "file"),
 			want: false,
 		},
 	}
@@ -140,8 +194,7 @@ func TestGitDirEdgeCases(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			got, err := GitDir(tt.path)
 			if err != nil {
-				// It's ok if the path doesn't exist for these edge case tests
-				return
+				t.Fatalf("GitDir(%q) returned unexpected error: %v", tt.path, err)
 			}
 			if got != tt.want {
 				t.Errorf("GitDir(%q) = %v, want %v", tt.path, got, tt.want)
@@ -150,28 +203,153 @@ func TestGitDirEdgeCases(t *testing.T) {
 	}
 }
 
-func TestGitDirPathSeparator(t *testing.T) {
-	// Test that the function correctly uses os.PathSeparator
-	// This is important for cross-platform compatibility
+// TestGitDirWithNestedGitDir tests a repo inside a .git-suffixed parent
+// directory. This is the nastiest combination: a real .git directory that
+// appears *after* a .git suffix in the path.
+func TestGitDirWithNestedGitDir(t *testing.T) {
+	root := t.TempDir()
 
-	// Create a path with the wrong separator for the current OS
-	var wrongSep string
-	if os.PathSeparator == '/' {
-		wrongSep = `\`
-	} else {
-		wrongSep = `/`
+	// Create: root/cheats.git/repo/.git/HEAD
+	//         root/cheats.git/repo/sheet
+	gitDir := filepath.Join(root, "cheats.git", "repo", ".git")
+	if err := os.MkdirAll(gitDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(gitDir, "HEAD"), []byte("ref: refs/heads/main\n"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(root, "cheats.git", "repo", "sheet"), []byte("content"), 0644); err != nil {
+		t.Fatal(err)
 	}
 
-	// Path with wrong separator should not be detected as git dir
-	path := fmt.Sprintf("some%spath%s.git%sfile", wrongSep, wrongSep, wrongSep)
-	isGit, err := GitDir(path)
+	tests := []struct {
+		name string
+		path string
+		want bool
+	}{
+		{
+			name: "sheet beside .git in .git-suffixed parent",
+			path: filepath.Join(root, "cheats.git", "repo", "sheet"),
+			want: false,
+		},
+		{
+			name: "file inside .git inside .git-suffixed parent",
+			path: filepath.Join(root, "cheats.git", "repo", ".git", "HEAD"),
+			want: true,
+		},
+	}
 
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := GitDir(tt.path)
 			if err != nil {
-		// Path doesn't exist, which is fine
-		return
+				t.Fatalf("GitDir(%q) returned unexpected error: %v", tt.path, err)
+			}
+			if got != tt.want {
+				t.Errorf("GitDir(%q) = %v, want %v", tt.path, got, tt.want)
+			}
+		})
+	}
+}
+
+// TestGitDirSubmoduleInsideDotGitSuffix tests a submodule (.git file)
+// inside a .git-suffixed parent directory.
+func TestGitDirSubmoduleInsideDotGitSuffix(t *testing.T) {
+	root := t.TempDir()
+
+	// Create: root/personal.git/submod/.git  (file)
+	//         root/personal.git/submod/sheet
+	subDir := filepath.Join(root, "personal.git", "submod")
+	if err := os.MkdirAll(subDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+	// .git as a file (submodule pointer)
+	if err := os.WriteFile(filepath.Join(subDir, ".git"), []byte("gitdir: ../../.git/modules/sub\n"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(subDir, "sheet"), []byte("content"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := GitDir(filepath.Join(subDir, "sheet"))
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got {
+		t.Error("GitDir should return false for sheet in submodule under .git-suffixed parent")
+	}
+}
+
+// TestGitDirIntegrationWalk simulates what sheets.Load does: walking a
+// directory tree and checking each path with GitDir. This verifies that
+// the function works correctly in the context of filepath.Walk, which is
+// how it is actually called.
+func TestGitDirIntegrationWalk(t *testing.T) {
+	root := setupGitDirTestTree(t)
+
+	// Walk the tree and collect which paths GitDir says to skip
+	var skipped []string
+	var visited []string
+
+	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+
+		isGit, err := GitDir(path)
+		if err != nil {
+			return err
+		}
+		if isGit {
+			skipped = append(skipped, path)
+		} else {
+			visited = append(visited, path)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Fatalf("Walk failed: %v", err)
+	}
+
+	// Files inside .git/ should be skipped
+	expectSkipped := []string{
+		filepath.Join(root, "repo", ".git", "HEAD"),
+	}
+	for _, want := range expectSkipped {
+		found := false
+		for _, got := range skipped {
+			if got == want {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Errorf("expected %q to be skipped, but it was not", want)
+		}
+	}
+
+	// Sheets should NOT be skipped — including the #711 case
+	expectVisited := []string{
+		filepath.Join(root, "plain", "sheet"),
+		filepath.Join(root, "repo", "sheet"),
+		filepath.Join(root, "submodule", "sheet"),
+		filepath.Join(root, "dotgit-suffix.git", "cheat", "sheet"),
+		filepath.Join(root, "dotgit-mid.git", "nested", "sheet"),
+		filepath.Join(root, ".hidden", "sheet"),
+	}
+	for _, want := range expectVisited {
+		found := false
+		for _, got := range visited {
+			if got == want {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Errorf("expected %q to be visited (not skipped), but it was not found in visited paths", want)
 		}
-
-	if isGit {
-		t.Errorf("GitDir() incorrectly detected git dir with wrong path separator")
 	}
 }