Fix the Python version select() mechanism to handle PY3-as-default
The target @bazel_tools//tools/python:python_version can be used with select() to determine the Python version in the current configuration. However, it was not updated when --incompatible_py3_is_default was added to switch the default to PY3. This meant that if neither --force_python nor --python_version was passed to the build, but --incompatible_py3_is_default was set, it would incorrectly return PY2 when the actual version was PY3. This CL updates this target's definition to take that flag into account.
Fixes the bug in (but does not close) #7615.
RELNOTES: None
PiperOrigin-RevId: 236642947
diff --git a/src/test/java/com/google/devtools/build/lib/rules/python/BUILD b/src/test/java/com/google/devtools/build/lib/rules/python/BUILD
index 8c62fd5..330b2c9 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/python/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/rules/python/BUILD
@@ -150,7 +150,6 @@
name = "PythonVersionSelectTest",
srcs = ["PythonVersionSelectTest.java"],
deps = [
- ":PythonTestUtils",
"//src/main/java/com/google/devtools/build/lib:build-base",
"//src/main/java/com/google/devtools/build/lib/actions",
"//src/main/java/com/google/devtools/build/lib/collect/nestedset",
diff --git a/src/test/java/com/google/devtools/build/lib/rules/python/PythonVersionSelectTest.java b/src/test/java/com/google/devtools/build/lib/rules/python/PythonVersionSelectTest.java
index c954118..3ff0e53 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/python/PythonVersionSelectTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/python/PythonVersionSelectTest.java
@@ -15,7 +15,6 @@
package com.google.devtools.build.lib.rules.python;
import static com.google.common.truth.Truth.assertThat;
-import static com.google.devtools.build.lib.rules.python.PythonTestUtils.ensureDefaultIsPY2;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.analysis.FileProvider;
@@ -103,8 +102,6 @@
*/
@Test
public void selectOnPythonVersionTarget() throws Exception {
- // Expected results assume the default is PY2.
- ensureDefaultIsPY2();
// getRuleContext() doesn't populate the information needed to resolve select()s, and
// ConfiguredTarget doesn't allow us to test an end-to-end view of the behavior of a select().
// So this test has the select() control srcs and asserts on which one's in the files to build.
@@ -120,11 +117,19 @@
" }),",
")");
- // Default.
- doTestSelectOnPythonVersionTarget(py2);
+ // Neither --python_version nor --force_python, use default value.
+ doTestSelectOnPythonVersionTarget(py2, "--incompatible_py3_is_default=false");
+ doTestSelectOnPythonVersionTarget(
+ py3,
+ "--incompatible_py3_is_default=true",
+ // PythonConfiguration has a validation check requiring that the new transition semantics be
+ // enabled before we're allowed to set the default to PY3.
+ "--incompatible_allow_python_version_transitions=true");
+
// No --python_version, trust --force_python.
doTestSelectOnPythonVersionTarget(py2, "--force_python=PY2");
doTestSelectOnPythonVersionTarget(py3, "--force_python=PY3");
+
// --python_version overrides --force_python.
doTestSelectOnPythonVersionTarget(py2, "--python_version=PY2");
doTestSelectOnPythonVersionTarget(py2, "--python_version=PY2", "--force_python=PY2");
diff --git a/tools/python/python_version.bzl b/tools/python/python_version.bzl
index 05260e1..8bb45b8 100644
--- a/tools/python/python_version.bzl
+++ b/tools/python/python_version.bzl
@@ -20,9 +20,6 @@
_PY2 = "PY2"
_PY3 = "PY3"
-# Keep in sync with PythonVersion.DEFAULT_TARGET_VALUE.
-_DEFAULT_PYTHON_VERSION = "PY2"
-
def _python_version_flag_impl(ctx):
# Version is determined using the same logic as in PythonOptions#getPythonVersion:
#
@@ -34,7 +31,7 @@
elif ctx.attr.force_python_flag != _UNSET:
version = ctx.attr.force_python_flag
else:
- version = _DEFAULT_PYTHON_VERSION
+ version = _PY3 if ctx.attr.incompatible_py3_is_default_flag else _PY2
if version not in ["PY2", "PY3"]:
fail("Internal error: _python_version_flag should only be able to " +
@@ -46,6 +43,7 @@
attrs = {
"force_python_flag": attr.string(mandatory = True, values = [_PY2, _PY3, _UNSET]),
"python_version_flag": attr.string(mandatory = True, values = [_PY2, _PY3, _UNSET]),
+ "incompatible_py3_is_default_flag": attr.bool(mandatory = True),
},
)
@@ -60,7 +58,7 @@
"""
# Config settings for the underlying native flags we depend on:
- # --force_python and --python_version.
+ # --force_python, --python_version, and --incompatible_py3_is_default.
native.config_setting(
name = "_force_python_setting_PY2",
values = {"force_python": "PY2"},
@@ -81,6 +79,16 @@
values = {"python_version": "PY3"},
visibility = ["//visibility:private"],
)
+ native.config_setting(
+ name = "_incompatible_py3_is_default_setting_false",
+ values = {"incompatible_py3_is_default": "false"},
+ visibility = ["//visibility:private"],
+ )
+ native.config_setting(
+ name = "_incompatible_py3_is_default_setting_true",
+ values = {"incompatible_py3_is_default": "true"},
+ visibility = ["//visibility:private"],
+ )
_python_version_flag(
name = name,
@@ -94,5 +102,9 @@
":_python_version_setting_PY3": _PY3,
"//conditions:default": _UNSET,
}),
+ incompatible_py3_is_default_flag = select({
+ ":_incompatible_py3_is_default_setting_false": False,
+ ":_incompatible_py3_is_default_setting_true": True,
+ }),
visibility = ["//visibility:public"],
)
