Automatically enable worker ENVIRONMENT when needed (#24525)

- Similar to #14151 but for more combos.
 - Fixes #14162.

Author: RReverser

ChangeLog.md

@@ -20,7 +20,8 @@ See docs/process.md for more on how version tagging works.
 
 4.0.11 (in development)
 -----------------------
-
+- The `ENVIRONMENT` setting will now be automatically updated to include
+  `worker` if multi-threading is enabled. (#24525)
 
 4.0.10 - 06/07/25
 -----------------

test/test_browser.py

@@ -3923,7 +3923,7 @@ def test_pthread_once(self):
 
   # Test against a certain thread exit time handling bug by spawning tons of threads.
   def test_pthread_spawns(self):
-    self.btest_exit('pthread/test_pthread_spawns.cpp', emcc_args=['-O3', '-pthread', '-sPTHREAD_POOL_SIZE=8', '--closure=1', '-sENVIRONMENT=web,worker'])
+    self.btest_exit('pthread/test_pthread_spawns.cpp', emcc_args=['-O3', '-pthread', '-sPTHREAD_POOL_SIZE=8', '--closure=1', '-sENVIRONMENT=web'])
 
   # It is common for code to flip volatile global vars for thread control. This is a bit lax, but nevertheless, test whether that
   # kind of scheme will work with Emscripten as well.
@@ -5115,7 +5115,7 @@ def test_system(self):
   # Tests the hello_wasm_worker.c documentation example code.
   @also_with_minimal_runtime
   def test_wasm_worker_hello(self):
-    self.btest_exit('wasm_worker/hello_wasm_worker.c', emcc_args=['-sWASM_WORKERS', '-sENVIRONMENT=web,worker'])
+    self.btest_exit('wasm_worker/hello_wasm_worker.c', emcc_args=['-sWASM_WORKERS', '-sENVIRONMENT=web'])
 
   def test_wasm_worker_hello_minimal_runtime_2(self):
     self.btest_exit('wasm_worker/hello_wasm_worker.c', emcc_args=['-sWASM_WORKERS', '-sMINIMAL_RUNTIME=2'])
@@ -5583,7 +5583,7 @@ def test_webpack(self, es6):
     else:
       copytree(test_file('webpack'), '.')
       outfile = 'src/hello.js'
-    self.compile_btest('hello_world.c', ['-sEXIT_RUNTIME', '-sMODULARIZE', '-sENVIRONMENT=web,worker', '-o', outfile])
+    self.compile_btest('hello_world.c', ['-sEXIT_RUNTIME', '-sMODULARIZE', '-sENVIRONMENT=web', '-o', outfile])
     self.run_process(shared.get_npm_cmd('webpack') + ['--mode=development', '--no-devtool'])
     # Webpack doesn't bundle the wasm file by default so we need to copy it
     # TODO(sbc): Look into plugins that do bundling.
@@ -5593,14 +5593,14 @@ def test_webpack(self, es6):
   @also_with_threads
   def test_vite(self):
     copytree(test_file('vite'), '.')
-    self.compile_btest('hello_world.c', ['-sEXIT_RUNTIME', '-sENVIRONMENT=web,worker', '-o', 'hello.mjs'])
+    self.compile_btest('hello_world.c', ['-sEXIT_RUNTIME', '-sENVIRONMENT=web', '-o', 'hello.mjs'])
     self.run_process(shared.get_npm_cmd('vite') + ['build'])
     self.run_browser('dist/index.html', '/report_result?exit:0')
 
   @also_with_threads
   def test_rollup(self):
     copytree(test_file('rollup'), '.')
-    self.compile_btest('hello_world.c', ['-sEXIT_RUNTIME', '-o', 'hello.mjs'])
+    self.compile_btest('hello_world.c', ['-sEXIT_RUNTIME', '-sENVIRONMENT=web', '-o', 'hello.mjs'])
     self.run_process(shared.get_npm_cmd('rollup') + ['--config'])
     # Rollup doesn't bundle the wasm file by default so we need to copy it
     # TODO(sbc): Look into plugins that do bundling.

test/test_core.py

@@ -9176,8 +9176,6 @@ def test_fpic_static(self):
   # @also_with_standalone_wasm(impure=True)
   @node_pthreads
   def test_pthread_create(self):
-    # test that the node environment can be specified by itself, and that still
-    # works with pthreads (even though we did not specify 'node,worker')
     self.set_setting('ENVIRONMENT', 'node')
     self.set_setting('STRICT')
     self.do_run_in_out_file_test('core/pthread/create.c')
@@ -9194,8 +9192,7 @@ def test_pthread_c11_threads(self, args):
     self.set_setting('PTHREADS_DEBUG')
     if not self.has_changed_setting('INITIAL_MEMORY'):
       self.set_setting('INITIAL_MEMORY', '64mb')
-    # test that the node and worker environments can be specified
-    self.set_setting('ENVIRONMENT', 'node,worker')
+    self.set_setting('ENVIRONMENT', 'node')
     self.do_run_in_out_file_test('pthread/test_pthread_c11_threads.c')
 
   @node_pthreads

test/test_other.py

@@ -11844,8 +11844,8 @@ def test_minimal_runtime_code_size(self, test_name, wasm2js, compare_js_output=F
                            '-lGL',
                            '-sMODULARIZE']
     hello_webgl2_sources = hello_webgl_sources + ['-sMAX_WEBGL_VERSION=2']
-    hello_wasm_worker_sources = [test_file('wasm_worker/wasm_worker_code_size.c'), '-sWASM_WORKERS', '-sENVIRONMENT=web,worker']
-    audio_worklet_sources = [test_file('webaudio/audioworklet.c'), '-sWASM_WORKERS', '-sAUDIO_WORKLET', '-sENVIRONMENT=web,worker', '-sTEXTDECODER=1']
+    hello_wasm_worker_sources = [test_file('wasm_worker/wasm_worker_code_size.c'), '-sWASM_WORKERS', '-sENVIRONMENT=web']
+    audio_worklet_sources = [test_file('webaudio/audioworklet.c'), '-sWASM_WORKERS', '-sAUDIO_WORKLET', '-sENVIRONMENT=web', '-sTEXTDECODER=1']
     embind_hello_sources = [test_file('code_size/embind_hello_world.cpp'), '-lembind']
     embind_val_sources = [test_file('code_size/embind_val_hello_world.cpp'),
                           '-lembind',
@@ -16208,3 +16208,14 @@ def test_unsupported_min_version_when_unsupported_env(self, env):
     self.assertContainedIf(f'var MIN_CHROME_VERSION = {unsupported};', src, env == 'node')
     self.assertContainedIf(f'var MIN_SAFARI_VERSION = {unsupported};', src, env == 'node')
     self.assertContainedIf(f'var MIN_FIREFOX_VERSION = {unsupported};', src, env == 'node')
+
+  @parameterized({
+    'web': ('web',),
+    'node': ('node',),
+  })
+  @parameterized({
+    'pthread': (['-pthread'],),
+    'wasm_workers': (['-sWASM_WORKERS'],),
+  })
+  def test_automatic_env_worker(self, env, emcc_args):
+    self.emcc(test_file('hello_world.c'), [f'-sENVIRONMENT={env}'] + emcc_args)

tools/link.py

@@ -162,6 +162,12 @@ def will_metadce():
 
 
 def setup_environment_settings():
+  # The worker environment is automatically added if any of the pthread or Worker features are used.
+  # Note: we need to actually modify ENVIRONMENTS variable here before the parsing,
+  # because some JS code reads it back so modifying parsed info alone is not sufficient.
+  if settings.SHARED_MEMORY and settings.ENVIRONMENT:
+    settings.ENVIRONMENT += ',worker'
+
   # Environment setting based on user input
   environments = settings.ENVIRONMENT.split(',')
   if any(x for x in environments if x not in VALID_ENVIRONMENTS):
@@ -171,6 +177,7 @@ def setup_environment_settings():
   settings.ENVIRONMENT_MAY_BE_WEBVIEW = not settings.ENVIRONMENT or 'webview' in environments
   settings.ENVIRONMENT_MAY_BE_NODE = not settings.ENVIRONMENT or 'node' in environments
   settings.ENVIRONMENT_MAY_BE_SHELL = not settings.ENVIRONMENT or 'shell' in environments
+  settings.ENVIRONMENT_MAY_BE_WORKER = not settings.ENVIRONMENT or 'worker' in environments
 
   if not settings.ENVIRONMENT_MAY_BE_NODE:
     if 'MIN_NODE_VERSION' in user_settings:
@@ -184,21 +191,6 @@ def setup_environment_settings():
         diagnostics.warning('unused-command-line-argument', 'ignoring %s because `web` and `webview` environments are not enabled', key)
       settings[key] = feature_matrix.UNSUPPORTED
 
-  # The worker case also includes Node.js workers when pthreads are
-  # enabled and Node.js is one of the supported environments for the build to
-  # run on. Node.js workers are detected as a combination of
-  # ENVIRONMENT_IS_WORKER and ENVIRONMENT_IS_NODE.
-  settings.ENVIRONMENT_MAY_BE_WORKER = \
-      not settings.ENVIRONMENT or \
-      'worker' in environments or \
-      (settings.ENVIRONMENT_MAY_BE_NODE and settings.PTHREADS)
-
-  if not settings.ENVIRONMENT_MAY_BE_WORKER and settings.PROXY_TO_WORKER:
-    exit_with_error('if you specify --proxy-to-worker and specify a "-sENVIRONMENT=" directive, it must include "worker" as a target! (Try e.g. -sENVIRONMENT=web,worker)')
-
-  if not settings.ENVIRONMENT_MAY_BE_WORKER and settings.SHARED_MEMORY:
-    exit_with_error('when building with multithreading enabled and a "-sENVIRONMENT=" directive is specified, it must include "worker" as a target! (Try e.g. -sENVIRONMENT=web,worker)')
-
 
 def generate_js_sym_info():
   """Runs the js compiler to generate a list of all symbols available in the JS
@@ -2016,8 +2008,7 @@ def run_embind_gen(options, wasm_target, js_syms, extra_settings):
   settings.PRE_JS_FILES = []
   settings.POST_JS_FILES = []
   # Force node since that is where the tool runs.
-  # When SHARED_MEMORY or PROXY_TO_WORKER are enabled, add the required 'worker' environment.
-  settings.ENVIRONMENT = 'node' + (',worker' if settings.SHARED_MEMORY or settings.PROXY_TO_WORKER else '')
+  settings.ENVIRONMENT = 'node'
   settings.MINIMAL_RUNTIME = 0
   # Required function to trigger TS generation.
   settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$callRuntimeCallbacks']