Add option to skip emscripten version check (#53)

Adds an option to skip emscripten version check. A user can either set
`SKIP_EMSCRIPTEN_VERSION_CHECK` env variable, or
`skip_emscripten_version_check` in the toml file.

I think it is useful in following scenarios:

- When we update the Emscripten version in Pyodide but it is not
released yet, so a user wants to build a package against newer
emscripten version.
- When a user needs a newer version of Emscripten to make their package
work. But the Emscripten version in Pyodide is not updated yet.

Of course, these scenarios will not work if two versions of Emscripten
are incompatible. But I think it is useful to provide this option as not
always

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Agriya Khetarpal <[email protected]>

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- Add `skip_emscripten_version_check` flag and SKIP_EMSCRIPTEN_VERSION_CHECK environment
+  variable to skip emscripten version check.
+  [#53](https://github.com/pyodide/pyodide-build/pull/53)
+
 ## [0.29.0] - 2024/09/19
 
 ### Added

pyodide_build/build_env.py

@@ -14,7 +14,7 @@
 from packaging.tags import Tag, compatible_tags, cpython_tags
 
 from pyodide_build import __version__
-from pyodide_build.common import search_pyproject_toml, xbuildenv_dirname
+from pyodide_build.common import search_pyproject_toml, to_bool, xbuildenv_dirname
 from pyodide_build.config import ConfigManager
 from pyodide_build.recipe import load_all_recipes
 
@@ -238,6 +238,10 @@ def get_emscripten_version_info() -> str:
 
 
 def check_emscripten_version() -> None:
+    skip = get_build_flag("SKIP_EMSCRIPTEN_VERSION_CHECK")
+    if to_bool(skip):
+        return
+
     needed_version = emscripten_version()
     try:
         version_info = get_emscripten_version_info()
@@ -248,8 +252,10 @@ def check_emscripten_version() -> None:
     installed_version = None
     try:
         for x in reversed(version_info.partition("\n")[0].split(" ")):
-            if re.match(r"[0-9]+\.[0-9]+\.[0-9]+", x):
-                installed_version = x
+            # (X.Y.Z) or (X.Y.Z)-git
+            match = re.match(r"(\d+\.\d+\.\d+)(-\w+)?", x)
+            if match:
+                installed_version = match.group(1)
                 break
     except Exception:
         raise RuntimeError("Failed to determine Emscripten version.") from None

pyodide_build/common.py

@@ -440,3 +440,10 @@ def search_pyproject_toml(
             raise ValueError(f"Could not parse {pyproject_file}.") from e
 
     return None, None
+
+
+def to_bool(value: str) -> bool:
+    """
+    Convert a string to a boolean value. Useful for parsing environment variables.
+    """
+    return value.lower() not in {"", "0", "false", "no", "off"}

pyodide_build/config.py

@@ -174,6 +174,7 @@ def to_env(self) -> dict[str, str]:
     "home": "HOME",
     "path": "PATH",
     "zip_compression_level": "PYODIDE_ZIP_COMPRESSION_LEVEL",
+    "skip_emscripten_version_check": "SKIP_EMSCRIPTEN_VERSION_CHECK",
     # maintainer only
     "_f2c_fixes_wrapper": "_F2C_FIXES_WRAPPER",
 }
@@ -188,6 +189,7 @@ def to_env(self) -> dict[str, str]:
     "ldflags",
     "rust_toolchain",
     "meson_cross_file",
+    "skip_emscripten_version_check",
     # maintainer only
     "_f2c_fixes_wrapper",
 }
@@ -205,6 +207,7 @@ def to_env(self) -> dict[str, str]:
     "rust_toolchain": "nightly-2024-01-29",
     # Other configuration
     "pyodide_jobs": "1",
+    "skip_emscripten_version_check": "0",
     # maintainer only
     "_f2c_fixes_wrapper": "",
 }

pyodide_build/tests/test_build_env.py

@@ -165,6 +165,12 @@ def get_emscripten_version_info():
 """
     build_env.check_emscripten_version()
 
+    s = f"""\
+emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) {build_env.emscripten_version()}-git
+clang version 15.0.0 (https://github.com/llvm/llvm-project 7effcbda49ba32991b8955821b8fdbd4f8f303e2)
+"""
+    build_env.check_emscripten_version()
+
     def get_emscripten_version_info():  # type: ignore[no-redef]
         raise FileNotFoundError()
 
@@ -179,6 +185,16 @@ def get_emscripten_version_info():  # type: ignore[no-redef]
         build_env.check_emscripten_version()
 
 
+def test_check_emscripten_version_skip(dummy_xbuildenv, monkeypatch, reset_cache):
+    with pytest.raises(RuntimeError):
+        monkeypatch.setenv("SKIP_EMSCRIPTEN_VERSION_CHECK", "0")
+        build_env.check_emscripten_version()
+
+    reset_cache()
+    monkeypatch.setenv("SKIP_EMSCRIPTEN_VERSION_CHECK", "1")
+    build_env.check_emscripten_version()
+
+
 def test_wheel_paths(dummy_xbuildenv):
     from pathlib import Path