Fix filesystem root detection for windows

Author: kbwo

denops/gin/git/finder.ts

@@ -1,4 +1,4 @@
-import { resolve, SEPARATOR } from "jsr:@std/path@^1.0.0";
+import { resolve } from "jsr:@std/path@^1.0.0";
 import { Cache } from "jsr:@lambdalisue/ttl-cache@^1.0.0";
 import { execute } from "./process.ts";
 import { decodeUtf8 } from "../util/text.ts";
@@ -7,6 +7,17 @@ const ttl = 30000; // seconds
 const cacheWorktree = new Cache<string, string | Error>(ttl);
 const cacheGitdir = new Cache<string, string | Error>(ttl);
 
+/**
+ * Check if we've reached the filesystem root by comparing a path with its parent.
+ * This works cross-platform (Windows, Linux, Mac).
+ *
+ * @param currentPath - The path to check
+ * @returns true if the path is the filesystem root, false otherwise
+ */
+function isFilesystemRoot(currentPath: string): boolean {
+  return currentPath === resolve(currentPath, "..");
+}
+
 /**
  * Find a root path of a git working directory.
  *
@@ -20,10 +31,7 @@ export async function findWorktree(cwd: string): Promise<string> {
     try {
       // Search upward from current directory to find worktree root
       let currentPath = path;
-      while (
-        currentPath && currentPath !== "/" &&
-        currentPath !== resolve(currentPath, "..")
-      ) {
+      while (!isFilesystemRoot(currentPath)) {
         if (await isWorktreeRoot(currentPath)) {
           result = currentPath;
           cacheWorktree.set(path, result);
@@ -38,7 +46,7 @@ export async function findWorktree(cwd: string): Promise<string> {
         "--show-superproject-working-tree",
       ]);
     } catch (e) {
-      result = e;
+      result = e as Error;
     }
     cacheWorktree.set(path, result);
     return result;
@@ -62,7 +70,7 @@ export async function findGitdir(cwd: string): Promise<string> {
     try {
       result = await revParse(path, ["--git-dir"]);
     } catch (e) {
-      result = e;
+      result = e as Error;
     }
     cacheGitdir.set(path, result);
     return result;

denops/gin/git/finder_test.ts

@@ -67,6 +67,61 @@ Deno.test({
   sanitizeOps: false,
 });
 
+Deno.test({
+  name: "findWorktree() returns a root path for worktree inside .git directory",
+  fn: async () => {
+    await using sbox = await prepare();
+    // Create a worktree inside .git/workspaces/ directory
+    await Deno.mkdir(join(".git", "workspaces"), { recursive: true });
+    await $`git worktree add -b workspace-test .git/workspaces/test main`;
+
+    // Change to a subdirectory within the worktree
+    await Deno.mkdir(join(".git", "workspaces", "test", "subdir"), {
+      recursive: true,
+    });
+    Deno.chdir(join(".git", "workspaces", "test", "subdir"));
+
+    // findWorktree should return the worktree root, not the main repository root
+    assertEquals(
+      await findWorktree("."),
+      join(sbox.path, ".git", "workspaces", "test"),
+    );
+    // An internal cache will be used for the following call
+    assertEquals(
+      await findWorktree("."),
+      join(sbox.path, ".git", "workspaces", "test"),
+    );
+  },
+  sanitizeResources: false,
+  sanitizeOps: false,
+});
+
+Deno.test({
+  name: "findGitdir() returns a gitdir path for worktree inside .git directory",
+  fn: async () => {
+    await using sbox = await prepare();
+    // Create a worktree inside .git/workspaces/ directory
+    await Deno.mkdir(join(".git", "workspaces"), { recursive: true });
+    await $`git worktree add -b workspace-test2 .git/workspaces/test2 main`;
+
+    // Change to the worktree
+    Deno.chdir(join(".git", "workspaces", "test2"));
+
+    // findGitdir should return the correct gitdir for this worktree
+    assertEquals(
+      await findGitdir("."),
+      join(sbox.path, ".git", "worktrees", "test2"),
+    );
+    // An internal cache will be used for the following call
+    assertEquals(
+      await findGitdir("."),
+      join(sbox.path, ".git", "worktrees", "test2"),
+    );
+  },
+  sanitizeResources: false,
+  sanitizeOps: false,
+});
+
 Deno.test({
   name:
     "findGitdir() throws an error if the path is not in a git working directory",