In pyodide venv, redirect python -m pip to run in host environment (#3761)

docs/project/changelog.md

@@ -43,6 +43,9 @@ myst:
   version 0.23.0 because of missing `python_stdlib.zip`.
   {pr}`3760`
 
+- {{ Fix }} `python -m pip` works correctly in the Pyodide venv now.
+  {pr}`3761`
+
 ### Build System
 
 - {{ Fix }} Fix `PYODIDE_ROOT` to point the correct directory when running out-of-tree build.

src/templates/python

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 ":" /* << "EOF"
 This file is a bash/node polyglot. This is needed for a few reasons:
 
@@ -21,6 +21,11 @@ inside the virtualenv the proper shell code is executed.
 EOF
 # bash
 set -e
+if [[ $1 == "-m" ]] && [[ $2 == "pip" ]]; then
+    # redirect python -m pip to execute in host environment
+    shift 1
+    exec $@
+fi
 
 which node > /dev/null  || { \
     >&2 echo "No node executable found on the path" && exit 1; \

src/tests/test_cmdline_runner.py

@@ -111,6 +111,25 @@ def test_dash_m(selenium):
     assert result.stdout.strip() == f"Emscripten-{emscripten_version()}-wasm32-32bit"
 
 
+@only_node
+def test_dash_m_pip(selenium, monkeypatch, tmp_path):
+    import os
+
+    monkeypatch.setenv("PATH", str(tmp_path), prepend=":")
+    pip_path = tmp_path / "pip"
+    pip_path.write_text("echo 'pip got' $@")
+    os.chmod(pip_path, 0o777)
+
+    result = subprocess.run(
+        [script_path, "-m", "pip", "install", "pytest"],
+        capture_output=True,
+        encoding="utf8",
+    )
+    assert result.returncode == 0
+    assert result.stderr == ""
+    assert result.stdout.strip() == "pip got install pytest"
+
+
 @only_node
 def test_invalid_cmdline_option(selenium):
     result = subprocess.run([script_path, "-c"], capture_output=True, encoding="utf8")