fix: improve nested git repository detection logic

- Fix path filtering to correctly expect 'file' type for HEAD files instead of 'folder'
- Use Node's path module for robust cross-platform path manipulation
- Update tests to match the corrected logic

Author: daniel-lxs

src/services/checkpoints/ShadowCheckpointService.ts

@@ -162,24 +162,40 @@ export abstract class ShadowCheckpointService extends EventEmitter {
 
 	private async getNestedGitRepository(): Promise<string | null> {
 		try {
-			// Find all .git directories that are not at the root level.
+			// Find all .git/HEAD files that are not at the root level.
 			const args = ["--files", "--hidden", "--follow", "-g", "**/.git/HEAD", this.workspaceDir]
 
 			const gitPaths = await executeRipgrep({ args, workspacePath: this.workspaceDir })
 
 			// Filter to only include nested git directories (not the root .git).
-			const nestedGitPaths = gitPaths.filter(
-				({ type, path }) =>
-					type === "folder" && path.includes(".git") && !path.startsWith(".git") && path !== ".git",
-			)
+			// Since we're searching for HEAD files, we expect type to be "file"
+			const nestedGitPaths = gitPaths.filter(({ type, path: filePath }) => {
+				// Check if it's a file and is a nested .git/HEAD (not at root)
+				if (type !== "file") return false
+
+				// Ensure it's a .git/HEAD file and not the root one
+				const normalizedPath = filePath.replace(/\\/g, "/")
+				return (
+					normalizedPath.includes(".git/HEAD") &&
+					!normalizedPath.startsWith(".git/") &&
+					normalizedPath !== ".git/HEAD"
+				)
+			})
 
 			if (nestedGitPaths.length > 0) {
-				// Get the first nested git repository path (remove .git/HEAD from the path)
-				const firstNestedPath = nestedGitPaths[0].path.replace(/[\/\\]\.git[\/\\]HEAD$/, "")
-				const absolutePath = path.join(this.workspaceDir, firstNestedPath)
+				// Get the first nested git repository path
+				// Remove .git/HEAD from the path to get the repository directory
+				const headPath = nestedGitPaths[0].path
+
+				// Use path module to properly extract the repository directory
+				// The HEAD file is at .git/HEAD, so we need to go up two directories
+				const gitDir = path.dirname(headPath) // removes HEAD, gives us .git
+				const repoDir = path.dirname(gitDir) // removes .git, gives us the repo directory
+
+				const absolutePath = path.join(this.workspaceDir, repoDir)
 
 				this.log(
-					`[${this.constructor.name}#getNestedGitRepository] found ${nestedGitPaths.length} nested git repositories, first at: ${firstNestedPath}`,
+					`[${this.constructor.name}#getNestedGitRepository] found ${nestedGitPaths.length} nested git repositories, first at: ${repoDir}`,
 				)
 				return absolutePath
 			}

src/services/checkpoints/__tests__/ShadowCheckpointService.spec.ts

@@ -421,11 +421,13 @@ describe.each([[RepoPerTaskCheckpointService, "RepoPerTaskCheckpointService"]])(
 					const searchPattern = args[4]
 
 					if (searchPattern.includes(".git/HEAD")) {
+						// Return the HEAD file path, not the .git directory
+						const headFilePath = path.join(path.relative(workspaceDir, nestedGitDir), "HEAD")
 						return Promise.resolve([
 							{
-								path: path.relative(workspaceDir, nestedGitDir),
-								type: "folder",
-								label: ".git",
+								path: headFilePath,
+								type: "file", // HEAD is a file, not a folder
+								label: "HEAD",
 							},
 						])
 					} else {