feat(fs): introduce canonicalize option to WalkOptions (#3679)

fs/expand_glob.ts

@@ -19,6 +19,12 @@ export interface ExpandGlobOptions extends Omit<GlobOptions, "os"> {
   exclude?: string[];
   includeDirs?: boolean;
   followSymlinks?: boolean;
+  /**
+   * Indicates whether the followed symlink's path should be canonicalized.
+   * This option works only if `followSymlinks` is not `false`.
+   * @default {true}
+   */
+  canonicalize?: boolean;
 }
 
 interface SplitPath {
@@ -80,6 +86,7 @@ export async function* expandGlob(
     globstar = true,
     caseInsensitive,
     followSymlinks,
+    canonicalize,
   }: ExpandGlobOptions = {},
 ): AsyncIterableIterator<WalkEntry> {
   const globOptions: GlobOptions = { extended, globstar, caseInsensitive };
@@ -134,6 +141,7 @@ export async function* expandGlob(
         skip: excludePatterns,
         maxDepth: globstar ? Infinity : 1,
         followSymlinks,
+        canonicalize,
       });
     }
     const globPattern = globToRegExp(globSegment, globOptions);
@@ -202,6 +210,7 @@ export function* expandGlobSync(
     globstar = true,
     caseInsensitive,
     followSymlinks,
+    canonicalize,
   }: ExpandGlobOptions = {},
 ): IterableIterator<WalkEntry> {
   const globOptions: GlobOptions = { extended, globstar, caseInsensitive };
@@ -256,6 +265,7 @@ export function* expandGlobSync(
         skip: excludePatterns,
         maxDepth: globstar ? Infinity : 1,
         followSymlinks,
+        canonicalize,
       });
     }
     const globPattern = globToRegExp(globSegment, globOptions);

fs/expand_glob_test.ts

@@ -156,3 +156,28 @@ Deno.test("expandGlobFollowSymlink", async function () {
   };
   assertEquals(await expandGlobArray("*", options), ["abc"]);
 });
+
+Deno.test("expandGlobFollowSymlink with canonicalize", async function () {
+  const options = {
+    ...EG_OPTIONS,
+    root: join(EG_OPTIONS.root!, "."),
+    followSymlinks: true,
+  };
+  assertEquals(
+    await expandGlobArray("**/abc", options),
+    ["abc", join("subdir", "abc")],
+  );
+});
+
+Deno.test("expandGlobFollowSymlink without canonicalize", async function () {
+  const options = {
+    ...EG_OPTIONS,
+    root: join(EG_OPTIONS.root!, "."),
+    followSymlinks: true,
+    canonicalize: false,
+  };
+  assertEquals(
+    await expandGlobArray("**/abc", options),
+    ["abc", join("link", "abc"), join("subdir", "abc")],
+  );
+});

fs/testdata/walk/symlink/b

@@ -0,0 +1 @@
+a

fs/walk.ts

@@ -75,6 +75,12 @@ export interface WalkOptions {
    * @default {false}
    */
   followSymlinks?: boolean;
+  /**
+   * Indicates whether the followed symlink's path should be canonicalized.
+   * This option works only if `followSymlinks` is not `false`.
+   * @default {true}
+   */
+  canonicalize?: boolean;
   /**
    * List of file extensions used to filter entries.
    * If specified, entries without the file extension specified by this option are excluded.
@@ -119,6 +125,7 @@ export async function* walk(
     includeDirs = true,
     includeSymlinks = true,
     followSymlinks = false,
+    canonicalize = true,
     exts = undefined,
     match = undefined,
     skip = undefined,
@@ -147,11 +154,14 @@ export async function* walk(
           }
           continue;
         }
-        path = await Deno.realPath(path);
+        const realPath = await Deno.realPath(path);
+        if (canonicalize) {
+          path = realPath;
+        }
         // Caveat emptor: don't assume |path| is not a symlink. realpath()
         // resolves symlinks but another process can replace the file system
         // entity with a different type of entity before we call lstat().
-        ({ isSymlink, isDirectory } = await Deno.lstat(path));
+        ({ isSymlink, isDirectory } = await Deno.lstat(realPath));
       }
 
       if (isSymlink || isDirectory) {
@@ -183,6 +193,7 @@ export function* walkSync(
     includeDirs = true,
     includeSymlinks = true,
     followSymlinks = false,
+    canonicalize = true,
     exts = undefined,
     match = undefined,
     skip = undefined,
@@ -216,11 +227,14 @@ export function* walkSync(
         }
         continue;
       }
-      path = Deno.realPathSync(path);
+      const realPath = Deno.realPathSync(path);
+      if (canonicalize) {
+        path = realPath;
+      }
       // Caveat emptor: don't assume |path| is not a symlink. realpath()
       // resolves symlinks but another process can replace the file system
       // entity with a different type of entity before we call lstat().
-      ({ isSymlink, isDirectory } = Deno.lstatSync(path));
+      ({ isSymlink, isDirectory } = Deno.lstatSync(realPath));
     }
 
     if (isSymlink || isDirectory) {

fs/walk_test.ts

@@ -74,12 +74,18 @@ Deno.test("[fs/walk] skip", async () =>
 
 // https://github.com/denoland/deno_std/issues/1358
 Deno.test("[fs/walk] symlink", async () =>
-  await assertWalkPaths("symlink", [".", "x", "x"], {
+  await assertWalkPaths("symlink", [".", "a", "a/z", "a", "a/z", "x", "x"], {
     followSymlinks: true,
   }));
 
+Deno.test("[fs/walk] symlink without canonicalize", async () =>
+  await assertWalkPaths("symlink", [".", "a", "a/z", "b", "b/z", "x", "y"], {
+    followSymlinks: true,
+    canonicalize: false,
+  }));
+
 Deno.test("[fs/walk] symlink without followSymlink", async () => {
-  await assertWalkPaths("symlink", [".", "x", "y"], {
+  await assertWalkPaths("symlink", [".", "a", "a/z", "b", "x", "y"], {
     followSymlinks: false,
   });
 });