[7.1.0] python: rules_python 0.22.0 -> 0.22.1 soas to register Python…

… toolchain by default (#21369)

A regression from upgrading to rules_python 0.22.0 is that a Python
toolchain is no longer registered by default (the prior 0.4.0 version
registered the "autodetecting" toolchain). Subsequent versions of
rules_python (0.23.0 or later) register a toolchain by default again,
but it's a downloaded runtime, which makes upgrading more involved.

To fix, upgrade to 0.22.1, which registers the autodetecting toolchain.
This restores the rules_python 0.4.0 behavior and should suffice until
bazel_tools is upgraded to 0.23.0 or later.

Fixes #20458

Closes #20514

PiperOrigin-RevId: 592578175
Change-Id: I707a4c96829063536f81cc10e144652102da1e7e

Fixes #21348

Co-authored-by: Richard Levasseur <[email protected]>

src/MODULE.tools

@@ -8,7 +8,7 @@ bazel_dep(name = "rules_cc", version = "0.0.9")
 bazel_dep(name = "rules_java", version = "7.1.0")
 bazel_dep(name = "rules_license", version = "0.0.3")
 bazel_dep(name = "rules_proto", version = "4.0.0")
-bazel_dep(name = "rules_python", version = "0.22.0")
+bazel_dep(name = "rules_python", version = "0.22.1")
 
 bazel_dep(name = "buildozer", version = "6.4.0.2")
 bazel_dep(name = "platforms", version = "0.0.7")

src/test/shell/bazel/python_version_test.sh

@@ -89,6 +89,34 @@ EOF
   expect_log "I am Python 3"
 }
 
+# Verify that a bzlmod without any workspace interference is able to
+# run Python rules.
+# This test is obsolete once the Python rules are removed from Bazel itself.
+function test_pure_bzlmod_can_build_py_binary() {
+  mkdir -p test
+
+  cat > test/BUILD << EOF
+py_binary(
+    name = "main3",
+    python_version = "PY3",
+    srcs = ["main3.py"],
+)
+EOF
+
+  touch test/main3.py
+
+  # Tell bzlmod to ignore workspace entirely
+  touch WORKSPACE.bzlmod
+  # Also clear out workspace, just to be safe. If workspace is triggered at all,
+  # then internal logic as part of the Python rules registration will trigger
+  # registering a Python toolchain, which we explicitly want to avoid.
+  cat > WORKSPACE
+
+  # Build instead of run. The autodetecting toolchain may not produce something
+  # that actually works (it could be a fake or some arbitrary system python).
+  bazel build --enable_bzlmod //test:main3 &> $TEST_log || fail "unable to build py binary"
+}
+
 # Test that access to runfiles works (in general, and under our test environment
 # specifically).
 function test_can_access_runfiles() {