Mark --preload-file as incompatible with MINIMAL_RUNTIME. NFC (emscripten-core#24910)

The file preloading mechanism relies on either `Module.preRun` or
`Module.calledRun`, neither of which are available with
`MINIMAL_RUNTIME`.

Author: sbc100

src/lib/libcore.js

@@ -2104,6 +2104,14 @@ addToLibrary({
     }
   },
 
+  $asyncLoad: async (url) => {
+    var arrayBuffer = await readAsync(url);
+  #if ASSERTIONS
+    assert(arrayBuffer, `Loading data file "${url}" failed (no arrayBuffer).`);
+  #endif
+    return new Uint8Array(arrayBuffer);
+  },
+
 #else // MINIMAL_RUNTIME
   // MINIMAL_RUNTIME doesn't support the runtimeKeepalive stuff
   $callUserCallback: (func) => func(),
@@ -2116,14 +2124,6 @@ addToLibrary({
     return x.startsWith('dynCall_') ? x : '_' + x;
   },
 
-  $asyncLoad: async (url) => {
-    var arrayBuffer = await readAsync(url);
-  #if ASSERTIONS
-    assert(arrayBuffer, `Loading data file "${url}" failed (no arrayBuffer).`);
-  #endif
-    return new Uint8Array(arrayBuffer);
-  },
-
   $alignMemory: (size, alignment) => {
 #if ASSERTIONS
     assert(alignment, "alignment argument is required");

src/lib/libfs.js

@@ -6,7 +6,6 @@
 
 var LibraryFS = {
   $FS__deps: ['$randomFill', '$PATH', '$PATH_FS', '$TTY', '$MEMFS',
-    '$FS_createPreloadedFile',
     '$FS_modeStringToFlags',
     '$FS_getMode',
     '$intArrayFromString',
@@ -27,6 +26,9 @@ var LibraryFS = {
 #endif
 #if ASSERTIONS
     '$strError', '$ERRNO_CODES',
+#endif
+#if !MINIMAL_RUNTIME
+    '$FS_createPreloadedFile',
 #endif
   ],
   $FS__postset: () => {
@@ -35,7 +37,9 @@ var LibraryFS = {
     addAtPostCtor('FS.ignorePermissions = false;');
     addAtExit('FS.quit();');
     return `
+#if !MINIMAL_RUNTIME
 FS.createPreloadedFile = FS_createPreloadedFile;
+#endif
 FS.staticInit();`;
   },
   $FS: {

src/lib/libfs_shared.js

@@ -29,7 +29,6 @@ addToLibrary({
     });
     return handled;
   },
-#endif
 
   // Preloads a file asynchronously. You can call this before run, for example in
   // preRun. run will be delayed until this file arrives and is set up.
@@ -48,9 +47,7 @@ addToLibrary({
     '$PATH_FS',
     '$FS_createDataFile',
     '$getUniqueRunDependency',
-#if !MINIMAL_RUNTIME
     '$FS_handledByPreloadPlugin',
-#endif
   ],
   $FS_createPreloadedFile: (parent, name, url, canRead, canWrite, onload, onerror, dontCreateFile, canOwn, preFinish) => {
     // TODO we should allow people to just pass in a complete filename instead
@@ -66,15 +63,12 @@ addToLibrary({
         onload?.();
         removeRunDependency(dep);
       }
-#if !MINIMAL_RUNTIME
-      if (FS_handledByPreloadPlugin(byteArray, fullname, finish, () => {
+      if (!FS_handledByPreloadPlugin(byteArray, fullname, finish, () => {
         onerror?.();
         removeRunDependency(dep);
       })) {
-        return;
+        finish(byteArray);
       }
-#endif
-      finish(byteArray);
     }
     addRunDependency(dep);
     if (typeof url == 'string') {
@@ -83,6 +77,8 @@ addToLibrary({
       processData(url);
     }
   },
+#endif
+
   // convert the 'r', 'r+', etc. to it's corresponding set of O_* flags
   $FS_modeStringToFlags: (str) => {
     var flagModes = {

test/code_size/test_codesize_hello_O0.json

@@ -1,10 +1,10 @@
 {
   "a.out.js": 22462,
-  "a.out.js.gz": 8336,
+  "a.out.js.gz": 8335,
   "a.out.nodebug.wasm": 15143,
   "a.out.nodebug.wasm.gz": 7452,
   "total": 37605,
-  "total_gz": 15788,
+  "total_gz": 15787,
   "sent": [
     "fd_write"
   ],

test/other/codesize/test_codesize_minimal_O0.expected.js

@@ -903,8 +903,8 @@ Module['FS_createPreloadedFile'] = FS.createPreloadedFile;
   'runtimeKeepalivePop',
   'callUserCallback',
   'maybeExit',
-  'asmjsMangle',
   'asyncLoad',
+  'asmjsMangle',
   'alignMemory',
   'mmapAlloc',
   'HandleAllocator',

test/test_other.py

@@ -1667,6 +1667,9 @@ def test_minimal_runtime_errors(self):
     err = self.expect_fail([EMCC, test_file('hello_world.c'), '-sMINIMAL_RUNTIME', '-sMINIMAL_RUNTIME_STREAMING_WASM_INSTANTIATION', '-oout.html', '-sSINGLE_FILE'])
     self.assertContained('emcc: error: MINIMAL_RUNTIME_STREAMING_WASM_INSTANTIATION is not compatible with SINGLE_FILE', err)
 
+    err = self.expect_fail([EMCC, test_file('hello_world.c'), '-sMINIMAL_RUNTIME', '--preload-file', 'foo'])
+    self.assertContained('emcc: error: MINIMAL_RUNTIME is not compatible with --preload-file', err)
+
   def test_export_all_and_exported_functions(self):
     # EXPORT_ALL should not export library functions by default.
     # This means that to export library function you also need to explicitly
@@ -16472,3 +16475,21 @@ def test_TextDecoder_invalid(self):
 
   def test_reallocarray(self):
     self.do_other_test('test_reallocarray.c')
+
+  def test_create_preloaded_file(self):
+    # Test that the FS.createPreloadedFile API works
+    create_file('post.js', "FS.createPreloadedFile('/', 'someotherfile.txt', 'somefile.txt', true, false);")
+    create_file('somefile.txt', 'hello')
+    create_file('main.c', r'''
+      #include <stdio.h>
+      #include <assert.h>
+      #include <sys/stat.h>
+
+      int main() {
+        struct stat buf;
+        int rtn = stat("someotherfile.txt", &buf);
+        assert(rtn == 0);
+        printf("done\n");
+        return 0;
+      }''')
+    self.do_runf('main.c', 'done\n', cflags=['-sFORCE_FILESYSTEM', '--post-js=post.js'])

tools/link.py

@@ -893,6 +893,9 @@ def limit_incoming_module_api():
     if options.use_preload_plugins or len(options.preload_files):
       exit_with_error('MODULARIZE=instance is not compatible with --embed-file/--preload-file')
 
+  if settings.MINIMAL_RUNTIME and len(options.preload_files):
+    exit_with_error('MINIMAL_RUNTIME is not compatible with --preload-file')
+
   if options.oformat in (OFormat.WASM, OFormat.BARE):
     if options.emit_tsd:
       exit_with_error('Wasm only output is not compatible --emit-tsd')