From ba6246a3ab7c8834aaae84d30325dc55e7dd0400 Mon Sep 17 00:00:00 2001
From: Ethan Smith <onebytegone@users.noreply.github.com>
Date: Mon, 26 Dec 2022 20:26:03 -0500
Subject: [PATCH] fix #2773: eval dependency symlinks instead of reading
 symlink target (#2774)

---
 CHANGELOG.md                |  4 ++++
 internal/fs/fs_real.go      | 38 +++++++++++++------------------------
 scripts/end-to-end-tests.js | 16 ++++++++++++++++
 3 files changed, 33 insertions(+), 25 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4c28ebd48e6..545fbfe74fa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -32,6 +32,10 @@
 
     However, this transformation is impossible if the code contains direct `eval` because direct `eval` "poisons" all containing scopes by preventing anything in those scopes from being renamed. That prevents esbuild from splitting up accesses to `foo` into two separate variables with different names. Previously esbuild still did this transformation but with two variables both named `foo`, which is a syntax error. With this release esbuild will now skip doing this transformation when direct `eval` is present to avoid generating code with a syntax error. This means that the generated code may no longer behave as intended since the behavior depends on the run-time strict mode setting instead of the strict mode setting present in the original source code. To fix this problem, you will need to remove the use of direct `eval`.
 
+* Fix a bundling scenario involving multiple symlinks ([#2773](https://github.com/evanw/esbuild/issues/2773), [#2774](https://github.com/evanw/esbuild/issues/2774))
+
+    This release contains a fix for a bundling scenario involving an import path where multiple path segments are symlinks. Previously esbuild was unable to resolve certain import paths in this scenario, but these import paths should now work starting with this release. This fix was contributed by [@onebytegone](https://github.com/onebytegone).
+
 ## 0.16.10
 
 * Change the default "legal comment" behavior again ([#2745](https://github.com/evanw/esbuild/issues/2745))
diff --git a/internal/fs/fs_real.go b/internal/fs/fs_real.go
index 454bd15b6f9..35b214b5c48 100644
--- a/internal/fs/fs_real.go
+++ b/internal/fs/fs_real.go
@@ -405,33 +405,21 @@ func (fs *realFS) kind(dir string, base string) (symlink string, kind EntryKind)
 
 	// Follow symlinks now so the cache contains the translation
 	if (mode & os.ModeSymlink) != 0 {
-		symlink = entryPath
-		linksWalked := 0
-		for {
-			linksWalked++
-			if linksWalked > 255 {
-				return // Error: too many links
-			}
-			link, err := os.Readlink(symlink)
-			if err != nil {
-				return // Skip over this entry
-			}
-			if !fs.fp.isAbs(link) {
-				link = fs.fp.join([]string{dir, link})
-			}
-			symlink = fs.fp.clean(link)
+		link, err := fs.fp.evalSymlinks(entryPath)
+		if err != nil {
+			return // Skip over this entry
+		}
 
-			// Re-run "lstat" on the symlink target
-			stat2, err2 := os.Lstat(symlink)
-			if err2 != nil {
-				return // Skip over this entry
-			}
-			mode = stat2.Mode()
-			if (mode & os.ModeSymlink) == 0 {
-				break
-			}
-			dir = fs.fp.dir(symlink)
+		// Re-run "lstat" on the symlink target to see if it's a file or not
+		stat2, err2 := os.Lstat(link)
+		if err2 != nil {
+			return // Skip over this entry
+		}
+		mode = stat2.Mode()
+		if (mode & os.ModeSymlink) != 0 {
+			return // This should no longer be a symlink, so this is unexpected
 		}
+		symlink = link
 	}
 
 	// We consider the entry either a directory or a file
diff --git a/scripts/end-to-end-tests.js b/scripts/end-to-end-tests.js
index 4dece1bd948..667c64c015c 100644
--- a/scripts/end-to-end-tests.js
+++ b/scripts/end-to-end-tests.js
@@ -441,6 +441,22 @@ if (process.platform !== 'win32') {
         export function fn() { return foo(); }
       `,
     }),
+
+    // These tests are for https://github.com/evanw/esbuild/issues/2773
+    test(['--bundle', 'in.js', '--outfile=node.js'], {
+      'in.js': `import {foo} from './baz/bar/foo'; if (foo !== 444) throw 'fail'`,
+      'foo/index.js': `import {qux} from '../qux'; export const foo = 123 + qux`,
+      'qux/index.js': `export const qux = 321`,
+      'bar/foo': { symlink: `../foo` },
+      'baz/bar': { symlink: `../bar` },
+    }),
+    test(['--bundle', 'in.js', '--outfile=node.js'], {
+      'in.js': `import {foo} from './baz/bar/foo'; if (foo !== 444) throw 'fail'`,
+      'foo/index.js': `import {qux} from '../qux'; export const foo = 123 + qux`,
+      'qux/index.js': `export const qux = 321`,
+      'bar/foo': { symlink: `TEST_DIR_ABS_PATH/foo` },
+      'baz/bar': { symlink: `TEST_DIR_ABS_PATH/bar` },
+    }),
   )
 }