[FS] Fix resolvePath handling of .. up from fs mountpoint (emscripten-core#23990)

hoodmane · web-flow · commit 06d53990ae0d · 2025-03-27T21:55:07.000Z
node.parent doesn't actually give us the parent if the node is a FS root. In that case, instead of using `node.parent` we should start over from the beginning. Resolves emscripten-core#23983.
diff --git a/src/lib/libfs.js b/src/lib/libfs.js
@@ -199,7 +199,12 @@ FS.staticInit();
 
           if (parts[i] === '..') {
             current_path = PATH.dirname(current_path);
-            current = current.parent;
+            if (FS.isRoot(current)) {
+              path = current_path + '/' + parts.slice(i + 1).join('/');
+              continue linkloop;
+            } else {
+              current = current.parent;
+            }
             continue;
           }
 
diff --git a/test/other/codesize/test_codesize_cxx_ctors1.gzsize b/test/other/codesize/test_codesize_cxx_ctors1.gzsize
@@ -1 +1 @@
-8219
+8232
diff --git a/test/other/codesize/test_codesize_cxx_ctors1.jssize b/test/other/codesize/test_codesize_cxx_ctors1.jssize
@@ -1 +1 @@
-19929
+19993
diff --git a/test/other/codesize/test_codesize_cxx_ctors2.gzsize b/test/other/codesize/test_codesize_cxx_ctors2.gzsize
@@ -1 +1 @@
-8207
+8221
diff --git a/test/other/codesize/test_codesize_cxx_ctors2.jssize b/test/other/codesize/test_codesize_cxx_ctors2.jssize
@@ -1 +1 @@
-19907
+19971
diff --git a/test/other/codesize/test_codesize_cxx_except.gzsize b/test/other/codesize/test_codesize_cxx_except.gzsize
@@ -1 +1 @@
-9217
+9231
diff --git a/test/other/codesize/test_codesize_cxx_except.jssize b/test/other/codesize/test_codesize_cxx_except.jssize
@@ -1 +1 @@
-23666
+23730
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm.gzsize b/test/other/codesize/test_codesize_cxx_except_wasm.gzsize
@@ -1 +1 @@
-8165
+8177
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm.jssize b/test/other/codesize/test_codesize_cxx_except_wasm.jssize
@@ -1 +1 @@
-19821
+19885
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm_legacy.gzsize b/test/other/codesize/test_codesize_cxx_except_wasm_legacy.gzsize
@@ -1 +1 @@
-8165
+8177
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm_legacy.jssize b/test/other/codesize/test_codesize_cxx_except_wasm_legacy.jssize
@@ -1 +1 @@
-19821
+19885
diff --git a/test/other/codesize/test_codesize_cxx_lto.gzsize b/test/other/codesize/test_codesize_cxx_lto.gzsize
@@ -1 +1 @@
-8234
+8245
diff --git a/test/other/codesize/test_codesize_cxx_lto.jssize b/test/other/codesize/test_codesize_cxx_lto.jssize
@@ -1 +1 @@
-20003
+20067
diff --git a/test/other/codesize/test_codesize_cxx_mangle.gzsize b/test/other/codesize/test_codesize_cxx_mangle.gzsize
@@ -1 +1 @@
-9255
+9268
diff --git a/test/other/codesize/test_codesize_cxx_mangle.jssize b/test/other/codesize/test_codesize_cxx_mangle.jssize
@@ -1 +1 @@
-23780
+23844
diff --git a/test/other/codesize/test_codesize_cxx_noexcept.gzsize b/test/other/codesize/test_codesize_cxx_noexcept.gzsize
@@ -1 +1 @@
-8219
+8232
diff --git a/test/other/codesize/test_codesize_cxx_noexcept.jssize b/test/other/codesize/test_codesize_cxx_noexcept.jssize
@@ -1 +1 @@
-19929
+19993
diff --git a/test/other/codesize/test_codesize_files_js_fs.gzsize b/test/other/codesize/test_codesize_files_js_fs.gzsize
@@ -1 +1 @@
-7528
+7542
diff --git a/test/other/codesize/test_codesize_files_js_fs.jssize b/test/other/codesize/test_codesize_files_js_fs.jssize
@@ -1 +1 @@
-18487
+18551
diff --git a/test/other/test_resolve_mountpoint_parent.c b/test/other/test_resolve_mountpoint_parent.c
@@ -0,0 +1,15 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <emscripten.h>
+#include "assert.h"
+
+int main(int argc, char **argv) {
+  EM_ASM({
+    FS.mkdir('/working');
+    FS.mkdir('/other');
+    FS.mount(NODEFS, { root: '.' }, '/working');
+  });
+  struct stat statBuf;
+  assert(stat("/working/../other", &statBuf) == 0);
+}
diff --git a/test/other/test_resolve_mountpoint_parent.out b/test/other/test_resolve_mountpoint_parent.out
diff --git a/test/test_other.py b/test/test_other.py
@@ -8191,6 +8191,11 @@ def test_realpath_2(self):
     create_file('Folder/testfile.txt', '')
     self.do_other_test('test_realpath_2.c', emcc_args=['--embed-file', 'testfile.txt', '--embed-file', 'Folder'])
 
+  @requires_node
+  @also_with_wasmfs
+  def test_resolve_mountpoint_parent(self):
+    self.do_other_test('test_resolve_mountpoint_parent.c', emcc_args=['-sFORCE_FILESYSTEM', '-lnodefs.js'])
+
   @with_env_modify({'EMCC_LOGGING': '0'})  # this test assumes no emcc output
   def test_no_warnings(self):
     # build once before to make sure system libs etc. exist
