Add install-emscripten CLI command

.github/workflows/main.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c # v6.0.0
         with:
-          python-version: "3.12"
+          python-version: "3.13"
 
       - name: Set up Node.js
         uses: actions/setup-node@2028fbc5c25fe9cf00d9f06a71cc4710d4507903 # v6.0.0
@@ -154,17 +154,13 @@ jobs:
           fi
           echo EMSCRIPTEN_VERSION=$(pyodide config get emscripten_version) >> $GITHUB_ENV
 
-      - name: Cache emsdk
-        uses: actions/cache@v4
-        with:
-          path: ${{ env.EMSDK_CACHE_FOLDER }}
-          key: ${{ env.EMSDK_CACHE_NUMBER }}-${{ env.EMSCRIPTEN_VERSION }}-${{ runner.os }}
-
       - name: Install Emscripten
-        uses: mymindstorm/setup-emsdk@6ab9eb1bda2574c4ddb79809fc9247783eaf9021 # v14
-        with:
-          version: ${{ env.EMSCRIPTEN_VERSION }}
-          actions-cache-folder: ${{env.EMSDK_CACHE_FOLDER}}
+        run: pyodide xbuildenv install-emscripten
+
+      - name: Activate emsdk
+        run: |
+          source $(pyodide config get pyodide_root)/../emsdk/emsdk_env.sh
+          emcc --version
 
       - name: Get number of cores on the runner
         id: get-cores

pyodide_build/cli/xbuildenv.py

@@ -2,7 +2,7 @@
 
 import typer
 
-from pyodide_build.build_env import local_versions
+from pyodide_build.build_env import get_build_flag, local_versions
 from pyodide_build.common import default_xbuildenv_path
 from pyodide_build.views import MetadataView
 from pyodide_build.xbuildenv import CrossBuildEnvManager
@@ -205,3 +205,31 @@ def _search(
         print(MetadataView.to_json(views))
     else:
         print(MetadataView.to_table(views))
+
+
+@app.command("install-emscripten")
+def _install_emscripten(
+    version: str = typer.Option(
+        None,
+        help="Emscripten version corresponding to the target Pyodide version",
+    ),
+    path: Path = typer.Option(DEFAULT_PATH, help="Pyodide cross-env path"),
+) -> None:
+    """
+    Install Emscripten SDK into the cross-build environment.
+
+    This command clones the emsdk repository, installs and activates the specified
+    Emscripten version, and applies Pyodide-specific patches.
+    """
+    check_xbuildenv_root(path)
+    manager = CrossBuildEnvManager(path)
+
+    if version is None:
+        version = get_build_flag("PYODIDE_EMSCRIPTEN_VERSION")
+
+    print("Installing emsdk...")
+
+    emsdk_dir = manager.install_emscripten(version)
+
+    print("Installing emsdk complete.")
+    print(f"Use `source {emsdk_dir}/emsdk_env.sh` to set up the environment.")

pyodide_build/tests/test_cli_install_emscripten.py

@@ -0,0 +1,224 @@
+"""Tests for install-emscripten CLI command"""
+
+import subprocess
+from pathlib import Path
+
+from typer.testing import CliRunner
+
+from pyodide_build.cli import xbuildenv
+
+runner = CliRunner()
+
+
+def test_install_emscripten_no_xbuildenv(tmp_path):
+    """Test that install-emscripten fails when no xbuildenv exists"""
+    envpath = Path(tmp_path) / ".xbuildenv"
+
+    result = runner.invoke(
+        xbuildenv.app,
+        [
+            "install-emscripten",
+            "--path",
+            str(envpath),
+        ],
+    )
+
+    assert result.exit_code != 0, result.stdout
+    assert "Cross-build environment not found" in result.stdout, result.stdout
+
+
+def test_install_emscripten_default_version(tmp_path, monkeypatch):
+    """Test installing Emscripten with default version"""
+    envpath = Path(tmp_path) / ".xbuildenv"
+    envpath.mkdir()
+
+    monkeypatch.setattr(
+        "pyodide_build.cli.xbuildenv.get_build_flag",
+        lambda name: "3.1.46",
+    )
+
+    called = {}
+
+    def fake_install(self, version):
+        called["version"] = version
+        return self.env_dir / "emsdk"
+
+    monkeypatch.setattr(
+        "pyodide_build.xbuildenv.CrossBuildEnvManager.install_emscripten",
+        fake_install,
+    )
+
+    result = runner.invoke(
+        xbuildenv.app,
+        [
+            "install-emscripten",
+            "--path",
+            str(envpath),
+        ],
+    )
+
+    assert result.exit_code == 0, result.stdout
+    assert "Installing emsdk..." in result.stdout, result.stdout
+    assert "Installing emsdk complete." in result.stdout, result.stdout
+    assert "Use `source" in result.stdout, result.stdout
+    assert "emsdk_env.sh` to set up the environment." in result.stdout, result.stdout
+    assert called["version"] == "3.1.46"
+
+
+def test_install_emscripten_specific_version(tmp_path, monkeypatch):
+    """Test installing Emscripten with a specific version"""
+    envpath = Path(tmp_path) / ".xbuildenv"
+    envpath.mkdir()
+
+    called = {}
+
+    def fake_install(self, version):
+        called["version"] = version
+        return self.env_dir / "emsdk"
+
+    monkeypatch.setattr(
+        "pyodide_build.xbuildenv.CrossBuildEnvManager.install_emscripten",
+        fake_install,
+    )
+
+    emscripten_version = "3.1.46"
+    result = runner.invoke(
+        xbuildenv.app,
+        [
+            "install-emscripten",
+            "--version",
+            emscripten_version,
+            "--path",
+            str(envpath),
+        ],
+    )
+
+    assert result.exit_code == 0, result.stdout
+    assert "Installing emsdk..." in result.stdout, result.stdout
+    assert "Installing emsdk complete." in result.stdout, result.stdout
+    assert called["version"] == emscripten_version
+
+
+def test_install_emscripten_with_existing_emsdk(tmp_path, monkeypatch):
+    """Test installing Emscripten when emsdk already exists (should pull updates)"""
+    envpath = Path(tmp_path) / ".xbuildenv"
+    envpath.mkdir()
+
+    existing_emsdk = envpath / "emsdk"
+    existing_emsdk.mkdir()
+
+    monkeypatch.setattr(
+        "pyodide_build.cli.xbuildenv.get_build_flag",
+        lambda name: "latest",
+    )
+
+    def fake_install(self, version):
+        assert version == "latest"
+        assert existing_emsdk.exists()
+        return existing_emsdk
+
+    monkeypatch.setattr(
+        "pyodide_build.xbuildenv.CrossBuildEnvManager.install_emscripten",
+        fake_install,
+    )
+
+    result = runner.invoke(
+        xbuildenv.app,
+        [
+            "install-emscripten",
+            "--path",
+            str(envpath),
+        ],
+    )
+
+    assert result.exit_code == 0, result.stdout
+    assert "Installing emsdk..." in result.stdout, result.stdout
+    assert "Installing emsdk complete." in result.stdout, result.stdout
+    assert str(existing_emsdk / "emsdk_env.sh") in result.stdout
+
+
+def test_install_emscripten_git_failure(tmp_path, monkeypatch):
+    """Test handling of git clone failure"""
+    envpath = Path(tmp_path) / ".xbuildenv"
+    envpath.mkdir()
+
+    monkeypatch.setattr(
+        "pyodide_build.xbuildenv.CrossBuildEnvManager.install_emscripten",
+        lambda self, version: (_ for _ in ()).throw(
+            subprocess.CalledProcessError(1, "git clone")
+        ),
+    )
+
+    result = runner.invoke(
+        xbuildenv.app,
+        [
+            "install-emscripten",
+            "--path",
+            str(envpath),
+        ],
+    )
+
+    # Should fail due to git clone error
+    assert result.exit_code != 0
+    assert isinstance(result.exception, subprocess.CalledProcessError)
+
+
+def test_install_emscripten_emsdk_install_failure(tmp_path, monkeypatch):
+    """Test handling of emsdk install command failure"""
+    envpath = Path(tmp_path) / ".xbuildenv"
+    envpath.mkdir()
+
+    monkeypatch.setattr(
+        "pyodide_build.xbuildenv.CrossBuildEnvManager.install_emscripten",
+        lambda self, version: (_ for _ in ()).throw(
+            subprocess.CalledProcessError(1, "./emsdk install")
+        ),
+    )
+
+    result = runner.invoke(
+        xbuildenv.app,
+        [
+            "install-emscripten",
+            "--path",
+            str(envpath),
+        ],
+    )
+
+    # Should fail due to emsdk install error
+    assert result.exit_code != 0
+    assert isinstance(result.exception, subprocess.CalledProcessError)
+
+
+def test_install_emscripten_output_format(tmp_path, monkeypatch):
+    """Test that the output message format is correct"""
+    envpath = Path(tmp_path) / ".xbuildenv"
+    envpath.mkdir()
+
+    monkeypatch.setattr(
+        "pyodide_build.cli.xbuildenv.get_build_flag",
+        lambda name: "latest",
+    )
+
+    expected_path = envpath / "emsdk"
+
+    monkeypatch.setattr(
+        "pyodide_build.xbuildenv.CrossBuildEnvManager.install_emscripten",
+        lambda self, version: expected_path,
+    )
+
+    result = runner.invoke(
+        xbuildenv.app,
+        [
+            "install-emscripten",
+            "--path",
+            str(envpath),
+        ],
+    )
+
+    assert result.exit_code == 0, result.stdout
+
+    # Verify output format - check for key messages (logger adds extra lines)
+    assert "Installing emsdk..." in result.stdout
+    assert "Installing emsdk complete." in result.stdout
+    assert "Use `source" in result.stdout
+    assert "emsdk_env.sh` to set up the environment." in result.stdout

pyodide_build/tests/test_cli_xbuildenv.py

@@ -93,6 +93,7 @@ def test_xbuildenv_install(tmp_path, mock_xbuildenv_url):
     assert result.exit_code == 0, result.stdout
     assert "Downloading Pyodide cross-build environment" in result.stdout, result.stdout
     assert "Installing Pyodide cross-build environment" in result.stdout, result.stdout
+    assert str(envpath.resolve()) in result.stdout, result.stdout
     assert (envpath / "xbuildenv").is_symlink()
     assert (envpath / "xbuildenv").resolve().exists()
 
@@ -121,8 +122,10 @@ def test_xbuildenv_install_version(tmp_path, fake_xbuildenv_releases_compatible)
     os.environ.pop(CROSS_BUILD_ENV_METADATA_URL_ENV_VAR, None)
 
     assert result.exit_code == 0, result.stdout
-    assert "Downloading Pyodide cross-build environment" in result.stdout, result.stdout
-    assert "Installing Pyodide cross-build environment" in result.stdout, result.stdout
+    assert "Pyodide cross-build environment installed at" in result.stdout, (
+        result.stdout
+    )
+    assert str(envpath.resolve()) in result.stdout, result.stdout
     assert (envpath / "xbuildenv").is_symlink()
     assert (envpath / "xbuildenv").resolve().exists()
     assert (envpath / "0.1.0").exists()
@@ -166,8 +169,10 @@ def test_xbuildenv_install_force_install(
     )
 
     assert result.exit_code == 0, result.stdout
-    assert "Downloading Pyodide cross-build environment" in result.stdout, result.stdout
-    assert "Installing Pyodide cross-build environment" in result.stdout, result.stdout
+    assert "Pyodide cross-build environment installed at" in result.stdout, (
+        result.stdout
+    )
+    assert str(envpath.resolve()) in result.stdout, result.stdout
     assert (envpath / "xbuildenv").is_symlink()
     assert (envpath / "xbuildenv").resolve().exists()
     assert (envpath / "0.1.0").exists()