gh-156780: Emscripten: add an embedding smoke test · python/cpython@c89eb2f · GitHub
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gh-156780: Emscripten: add an embedding smoke test
Nothing covers libpython linked into a program whose main() is not Python's: every wasm test builds through Platforms/emscripten, which always passes --enable-wasm-dynamic-linking. web_embed_test links libpython without -sMAIN_MODULE and without the interpreter's -sEXPORTED_FUNCTIONS, then imports from the stdlib zip and calls through the trampoline. It covers the EM_JS_DEPS and _PyRuntime regressions, not the suspending syscall paths, which it does not reach. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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‎.github/workflows/reusable-emscripten.yml‎

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‎Makefile.pre.in‎

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@@ -791,7 +791,7 @@ build_wasm: check-clean-src $(BUILDPYTHON) platform sharedmods \
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python-config checksharedmods $(BUILD_DETAILS)
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.PHONY: build_emscripten
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build_emscripten: build_wasm web_example web_example_pyrepl_jspi
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build_emscripten: build_wasm web_example web_example_pyrepl_jspi web_embed_test
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# Check that the source is clean when building out of source.
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.PHONY: check-clean-src
@@ -1118,6 +1118,25 @@ web_example/python.mjs web_example/python.wasm: $(BUILDPYTHON)
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cp python.mjs web_example/python.mjs
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cp python.wasm web_example/python.wasm
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WEB_EMBED_TEST_DIR=$(EMSCRIPTEN_DIR)/web_embed_test
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web_embed_test/stdlib.zip: $(ZIP_STDLIB)
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@mkdir -p web_embed_test
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@cp $< $@
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# Deliberately linked without $(LINKFORSHARED): an embedder gets neither
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# -sMAIN_MODULE nor the interpreter's -sEXPORTED_FUNCTIONS.
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web_embed_test/main.js: $(WEB_EMBED_TEST_DIR)/main.c $(LINK_PYTHON_DEPS) web_embed_test/stdlib.zip
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@mkdir -p web_embed_test
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$(LINKCC) $(PY_CORE_EXE_LDFLAGS) -o $@ $(WEB_EMBED_TEST_DIR)/main.c \
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$(LINK_PYTHON_OBJS) $(LIBS) $(MODLIBS) $(SYSLIBS) \
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-sALLOW_MEMORY_GROWTH -sINITIAL_MEMORY=64MB -sSTACK_SIZE=5MB \
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-sALLOW_TABLE_GROWTH -sFORCE_FILESYSTEM -sEXIT_RUNTIME \
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--preload-file web_embed_test/stdlib.zip@/lib/stdlib.zip
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.PHONY: web_embed_test
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web_embed_test: web_embed_test/main.js
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.PHONY: web_example
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web_example: web_example/python.mjs web_example/python.worker.mjs web_example/index.html web_example/server.py web_example/$(ZIP_STDLIB)
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@@ -3305,7 +3324,7 @@ clean-retain-profile: pycremoval
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find build -name '*.py[co]' -exec rm -f {} ';' || true
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-rm -f pybuilddir.txt
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-rm -f _bootstrap_python
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-rm -rf web_example python.mjs python.wasm python*.symbols python*.map
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-rm -rf web_example web_embed_test python.mjs python.wasm python*.symbols python*.map
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-rm -f Programs/_testembed Programs/_freeze_module
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-rm -rf Python/deepfreeze
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-rm -f Python/frozen_modules/*.h

‎Platforms/emscripten/web_embed_test/main.c‎

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/* Smoke test for libpython linked into a program whose main() is not Python's.
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*
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* Linked without -sMAIN_MODULE and without the interpreter's
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* -sEXPORTED_FUNCTIONS, so it fails if libpython depends on either.
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*/
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#include <Python.h>
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#include <stdio.h>
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// Imports come from the preloaded zip, len() goes through the call trampoline.
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static const char *SCRIPT =
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"import json, select\n"
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"select.poll().poll(0)\n"
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"print(json.dumps({'embedded': len('ok')}))\n";
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int main(void)
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{
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PyStatus status;
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PyConfig config;
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PyConfig_InitIsolatedConfig(&config);
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config.write_bytecode = 0;
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config.module_search_paths_set = 1;
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PyWideStringList_Append(&config.module_search_paths, L"/lib/stdlib.zip");
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PyConfig_SetBytesString(&config, &config.executable, "/embed");
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status = Py_InitializeFromConfig(&config);
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PyConfig_Clear(&config);
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if (PyStatus_Exception(status)) {
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puts("web_embed_test: Py_InitializeFromConfig failed");
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return 1;
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}
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if (PyRun_SimpleString(SCRIPT) != 0) {
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puts("web_embed_test: script failed");
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return 1;
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}
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Py_Finalize();
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puts("web_embed_test: ok");
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return 0;
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}

‎Platforms/emscripten/web_embed_test/run_test.sh‎

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