[libbrowser.js] Remove non-standard Module exports (#24269)

sbc100 · web-flow · commit 46988340f8db · 2025-05-07T18:33:12.000Z
Anyone who wants to use these functions on the Module object can export
them using e.g. `-sEXPORTED_FUNCTIONS=getUserMedia`.

As part of this I had to inject the export of `createContext` for SDL2
and SDL3 which were using `Module['createContext']` for some reason.
I'm working on upstream patches to remove this usage.
diff --git a/ChangeLog.md b/ChangeLog.md
@@ -23,9 +23,11 @@ See docs/process.md for more on how version tagging works.
 - libunwind was updated to LLVM 20.1.4. (#24251)
 - When using cmake the EMSCRIPTEN_FORCE_COMPILERS setting was reverted to
   being on by default due to issues that were found with disabling it. (#24223)
-- Embind symbols `InternalError`, `BindingError`, and `count_emval_handles` are
-  no longer exported by default. They can be exported using
-  `-sEXPORTED_RUNTIME_METHODS=InternalError,BindingError,count_emval_handles`
+- Several symbols from embind (`InternalError`, `BindingError`,
+  `count_emval_handles`) and from `libbrowser.py` (`requestFullscreen`,
+  `requestFullScreen`, `createContext`, `getUserMedia`, `setCanvasSize`) are no
+  longer exported by default. They can be exported using
+  `-sEXPORTED_RUNTIME_METHODS=requestFullscreen`, for example. (#24223, #24269)
 
 4.0.8 - 04/30/25
 ----------------
diff --git a/src/lib/libbrowser.js b/src/lib/libbrowser.js
@@ -17,16 +17,6 @@ var LibraryBrowser = {
 #endif
 #endif
   ],
-  $Browser__postset: `
-    // exports
-    Module['requestFullscreen'] = Browser.requestFullscreen;
-#if ASSERTIONS
-    Module['requestFullScreen'] = Browser.requestFullScreen;
-#endif
-    Module['setCanvasSize'] = Browser.setCanvasSize;
-    Module['getUserMedia'] = Browser.getUserMedia;
-    Module['createContext'] = Browser.createContext;
-  `,
 
   $Browser: {
     useWebGL: false,
@@ -591,6 +581,14 @@ var LibraryBrowser = {
     },
   },
 
+  $requestFullscreen: 'Browser.requestFullscreen',
+#if ASSERTIONS
+  $requestFullScreen: 'Browser.requestFullScreen',
+#endif
+  $setCanvasSize: 'Browser.setCanvasSize',
+  $getUserMedia: 'Browser.getUserMedia',
+  $createContext: 'Browser.createContext',
+
   emscripten_run_preload_plugins__deps: ['$PATH'],
   emscripten_run_preload_plugins__proxy: 'sync',
   emscripten_run_preload_plugins: (file, onload, onerror) => {
diff --git a/test/browser/test_sdl2_canvas_write.c b/test/browser/test_sdl2_canvas_write.c
@@ -63,7 +63,7 @@ int main(void) {
   if (SDL_Init(SDL_INIT_VIDEO) != 0)
     sdlError("SDL_Init");
 
-  window = SDL_CreateWindow("SDL 2 test", 0, 0, 256, 256, SDL_WINDOW_SHOWN);
+  window = SDL_CreateWindow("SDL2 test", 0, 0, 256, 256, SDL_WINDOW_SHOWN);
   if (window == NULL) {
     sdlError("SDL_CreateWindow");
   }
diff --git a/test/browser/test_sdl3_canvas_write.c b/test/browser/test_sdl3_canvas_write.c
@@ -69,7 +69,7 @@ int main(void) {
     sdlError("SDL_Init");
   }
 
-  window = SDL_CreateWindow("SDL 2 test", 256, 256, 0);
+  window = SDL_CreateWindow("SDL3 test", 256, 256, 0);
   if (window == NULL) {
     sdlError("SDL_CreateWindow");
   }
diff --git a/test/other/codesize/test_codesize_hello_O0.gzsize b/test/other/codesize/test_codesize_hello_O0.gzsize
@@ -1 +1 @@
-8292
+8312
diff --git a/test/other/codesize/test_codesize_hello_O0.jssize b/test/other/codesize/test_codesize_hello_O0.jssize
@@ -1 +1 @@
-22165
+22242
diff --git a/test/other/codesize/test_codesize_minimal_O0.gzsize b/test/other/codesize/test_codesize_minimal_O0.gzsize
@@ -1 +1 @@
-6595
+6617
diff --git a/test/other/codesize/test_codesize_minimal_O0.jssize b/test/other/codesize/test_codesize_minimal_O0.jssize
@@ -1 +1 @@
-17534
+17611
diff --git a/test/other/test_unoptimized_code_size.js.size b/test/other/test_unoptimized_code_size.js.size
@@ -1 +1 @@
-53603
+53705
diff --git a/test/other/test_unoptimized_code_size_strict.js.size b/test/other/test_unoptimized_code_size_strict.js.size
@@ -1 +1 @@
-51653
+51755
diff --git a/tools/ports/__init__.py b/tools/ports/__init__.py
@@ -10,6 +10,7 @@
 import shutil
 import glob
 import importlib.util
+from inspect import signature
 import sys
 import subprocess
 from typing import Set
@@ -427,9 +428,16 @@ def dfs(node):
   return stack
 
 
-def resolve_dependencies(port_set, settings):
+def resolve_dependencies(port_set, settings, cflags_only=False):
   def add_deps(node):
-    node.process_dependencies(settings)
+    sig = signature(node.process_dependencies)
+    if len(sig.parameters) == 2:
+      # The optional second parameter here is useful for ports that want
+      # to mutate linker-only settings.  Modifying these settings during the
+      # compile phase (or in a compile-only) command generates errors.
+      node.process_dependencies(settings, cflags_only)
+    else:
+      node.process_dependencies(settings)
     for d in node.deps:
       d, _ = split_port_options(d)
       if d not in ports_by_name:
@@ -524,10 +532,10 @@ def error_handler(message):
   return name
 
 
-def get_needed_ports(settings):
+def get_needed_ports(settings, cflags_only=False):
   # Start with directly needed ports, and transitively add dependencies
   needed = OrderedSet(p for p in ports if p.needed(settings))
-  resolve_dependencies(needed, settings)
+  resolve_dependencies(needed, settings, cflags_only)
   return needed
 
 
@@ -575,7 +583,7 @@ def add_cflags(args, settings): # noqa: U100
   if settings.USE_SDL == 1:
     args += ['-I' + Ports.get_include_dir('SDL')]
 
-  needed = get_needed_ports(settings)
+  needed = get_needed_ports(settings, cflags_only=True)
 
   # Now get (i.e. build) the ports in dependency order.  This is important because the
   # headers from one port might be needed before we can build the next.
diff --git a/tools/ports/sdl2.py b/tools/ports/sdl2.py
@@ -20,6 +20,12 @@ def get_lib_name(settings):
   return 'libSDL2' + ('-mt' if settings.PTHREADS else '') + '.a'
 
 
+def process_dependencies(settings, cflags_only):
+  if not cflags_only:
+    # SDL2 includes an internal reference to Module['createContext']
+    settings.EXPORTED_RUNTIME_METHODS.append('createContext')
+
+
 def get(ports, settings, shared):
   # get the port
   ports.fetch_project('sdl2', f'https://github.com/libsdl-org/SDL/archive/{TAG}.zip', sha512hash=HASH)
diff --git a/tools/ports/sdl3.py b/tools/ports/sdl3.py
@@ -23,6 +23,12 @@ def get_lib_name(settings):
   return 'libSDL3' + ('-mt' if settings.PTHREADS else '') + '.a'
 
 
+def process_dependencies(settings, cflags_only):
+  if not cflags_only:
+    # SDL3 includes an internal reference to Module['createContext']
+    settings.EXPORTED_RUNTIME_METHODS.append('createContext')
+
+
 def get(ports, settings, shared):
   # get the port
   ports.fetch_project('sdl3', f'https://github.com/libsdl-org/SDL/archive/{TAG}.zip', sha512hash=HASH)

Original file line number	Diff line number	Diff line change
`@@ -63,7 +63,7 @@ int main(void) {`
`63`	`63`	`if (SDL_Init(SDL_INIT_VIDEO) != 0)`
`64`	`64`	`sdlError("SDL_Init");`
`65`	`65`
`66`		`- window = SDL_CreateWindow("SDL 2 test", 0, 0, 256, 256, SDL_WINDOW_SHOWN);`
	`66`	`+ window = SDL_CreateWindow("SDL2 test", 0, 0, 256, 256, SDL_WINDOW_SHOWN);`
`67`	`67`	`if (window == NULL) {`
`68`	`68`	`sdlError("SDL_CreateWindow");`
`69`	`69`	`}`
Original file line number	Diff line number	Diff line change
`@@ -69,7 +69,7 @@ int main(void) {`
`69`	`69`	`sdlError("SDL_Init");`
`70`	`70`	`}`
`71`	`71`
`72`		`- window = SDL_CreateWindow("SDL 2 test", 256, 256, 0);`
	`72`	`+ window = SDL_CreateWindow("SDL3 test", 256, 256, 0);`
`73`	`73`	`if (window == NULL) {`
`74`	`74`	`sdlError("SDL_CreateWindow");`
`75`	`75`	`}`