Add 'incompatible_default_to_explicit_init_py' flag

    This effectively changes the default value of legacy_create_init to false.

    Technically, the attribute type has changed from boolean (default true) to tristate (default auto). Therefore, it is possible to see a semantic change in code that introspects a py_binary's or py_test's attrs dict (via native.existing_rules). We think it is unlikely this will break anyone, and in any case it is not currently possible to gate a rule's definition on an incompatible change flag.

    Closes #9271. Work toward #7386 and #10076.

    RELNOTES: [Python] Added flag --incomaptible_default_to_explicit_init_py to switch the default value of legacy_create_init to True. With this flag enabled, your py_binary and py_test targets will no longer behave as if empty __init__.py files were implicitly littered in your runfiles tree. See [#10076](bazelbuild/bazel#10076).
    PiperOrigin-RevId: 276526057

dataset/GitHub_Java/bazelbuild.bazel/src/main/java/com/google/devtools/build/lib/bazel/rules/python/BazelPyRuleClasses.java

@@ -229,7 +229,7 @@ The list of source (<code>.py</code>) files that are processed to create the tar
           These are created in every directory containing Python source code or
           shared libraries, and every parent directory of those directories, excluding the repo root
           directory. The default, auto, means true unless
-          <code>--incompatible_default_to_explicit_init_py</code> is used. If false, the user is
+          <code>--incompatible_remove_legacy_create_init</code> is used. If false, the user is
           responsible for creating (possibly empty) __init__.py files and adding them to the
           <code>srcs</code> of Python targets as required.
           <!-- #END_BLAZE_RULE.ATTRIBUTE --> */

dataset/GitHub_Java/bazelbuild.bazel/src/main/java/com/google/devtools/build/lib/rules/python/PyExecutable.java

@@ -122,7 +122,7 @@ public ConfiguredTarget create(RuleContext ruleContext)
    * If requested, creates empty __init__.py files for each manifest file.
    *
    * <p>We do this if the rule defines {@code legacy_create_init} and its value is true. Auto is
-   * treated as false iff {@code --incompatible_default_to_explicit_init_py} is given.
+   * treated as false iff {@code --incompatible_remove_legacy_Create_init_py} is given.
    *
    * <p>See {@link PythonUtils#getInitPyFiles} for details about how the files are created.
    */

dataset/GitHub_Java/bazelbuild.bazel/src/main/java/com/google/devtools/build/lib/rules/python/PythonConfiguration.java

@@ -23,7 +23,6 @@
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
-import com.google.devtools.build.lib.syntax.StarlarkValue;
 import com.google.devtools.build.lib.util.OS;
 import com.google.devtools.common.options.TriState;
 
@@ -36,7 +35,7 @@
     name = "py",
     doc = "A configuration fragment for Python.",
     category = SkylarkModuleCategory.CONFIGURATION_FRAGMENT)
-public class PythonConfiguration extends BuildConfiguration.Fragment implements StarlarkValue {
+public class PythonConfiguration extends BuildConfiguration.Fragment {
 
   private final PythonVersion version;
   private final PythonVersion defaultVersion;
@@ -90,7 +89,8 @@ public class PythonConfiguration extends BuildConfiguration.Fragment implements
    * Returns the Python version to use.
    *
    * <p>Specified using either the {@code --python_version} flag and {@code python_version} rule
-   * attribute (new API), or the {@code default_python_version} rule attribute (old API).
+   * attribute (new API), or the {@code --force_python} flag and {@code default_python_version} rule
+   * attribute (old API).
    */
   public PythonVersion getPythonVersion() {
     return version;
@@ -134,6 +134,11 @@ public String getOutputDirectoryName() {
   @Override
   public void reportInvalidOptions(EventHandler reporter, BuildOptions buildOptions) {
     PythonOptions opts = buildOptions.get(PythonOptions.class);
+    if (opts.forcePython != null && opts.incompatibleRemoveOldPythonVersionApi) {
+      reporter.handle(
+          Event.error(
+              "`--force_python` is disabled by `--incompatible_remove_old_python_version_api`"));
+    }
     if (opts.incompatiblePy3IsDefault && !opts.incompatibleAllowPythonVersionTransitions) {
       reporter.handle(
           Event.error(
@@ -162,7 +167,10 @@ public boolean buildTransitiveRunfilesTrees() {
     return buildTransitiveRunfilesTrees;
   }
 
-  /** Returns whether use of the {@code default_python_version} attribute is allowed. */
+  /**
+   * Returns whether use of {@code --force_python} flag and {@code default_python_version} attribute
+   * is allowed.
+   */
   public boolean oldPyVersionApiAllowed() {
     return oldPyVersionApiAllowed;
   }

dataset/GitHub_Java/bazelbuild.bazel/src/main/java/com/google/devtools/build/lib/rules/python/PythonConfigurationLoader.java

@@ -14,9 +14,9 @@
 package com.google.devtools.build.lib.rules.python;
 
 import com.google.common.collect.ImmutableSet;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration.Fragment;
 import com.google.devtools.build.lib.analysis.config.BuildOptions;
 import com.google.devtools.build.lib.analysis.config.ConfigurationFragmentFactory;
-import com.google.devtools.build.lib.analysis.config.Fragment;
 import com.google.devtools.build.lib.analysis.config.FragmentOptions;
 import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
 
@@ -39,6 +39,8 @@ public PythonConfiguration create(BuildOptions buildOptions)
         pythonOptions.getDefaultPythonVersion(),
         pythonOptions.buildPythonZip,
         pythonOptions.buildTransitiveRunfilesTrees,
+        /*oldPyVersionApiAllowed=*/ !pythonOptions.incompatibleRemoveOldPythonVersionApi,
+        /*useNewPyVersionSemantics=*/ pythonOptions.incompatibleAllowPythonVersionTransitions,
         /*py2OutputsAreSuffixed=*/ pythonOptions.incompatiblePy2OutputsAreSuffixed,
         /*disallowLegacyPyProvider=*/ pythonOptions.incompatibleDisallowLegacyPyProvider,
         /*useToolchains=*/ pythonOptions.incompatibleUsePythonToolchains,

dataset/GitHub_Java/bazelbuild.bazel/src/main/java/com/google/devtools/build/lib/rules/python/PythonOptions.java

@@ -79,7 +79,7 @@ public String getTypeDescription() {
         OptionMetadataTag.TRIGGERED_BY_ALL_INCOMPATIBLE_CHANGES
       },
       help =
-          "If true, disables use of the `default_python_version` "
+          "If true, disables use of the `--force_python` flag and the `default_python_version` "
               + "attribute for `py_binary` and `py_test`. Use the `--python_version` flag and "
               + "`python_version` attribute instead, which have exactly the same meaning. This "
               + "flag also disables `select()`-ing over `--host_force_python`.")
@@ -169,17 +169,25 @@ public String getTypeDescription() {
       OptionsParser.getOptionDefinitionByName(PythonOptions.class, "python_version");
 
   /**
-   * Deprecated machinery for setting the Python version; will be removed soon.
+   * This field should be either null (unset), {@code PY2}, or {@code PY3}. Other {@code
+   * PythonVersion} values do not represent distinct Python versions and are not allowed.
+   *
+   * <p>This flag is not accessible to the user when {@link #incompatibleRemoveOldPythonVersionApi}
+   * is true.
    *
-   * <p>Not in GraveyardOptions because we still want to prohibit users from select()ing on it.
+   * <p>Native rule logic should call {@link #getPythonVersion} / {@link #setPythonVersion} instead
+   * of accessing this option directly. BUILD/.bzl code should {@code select()} on {@code <tools
+   * repo>//tools/python:python_version} rather than on this option directly.
    */
   @Option(
       name = "force_python",
       defaultValue = "null",
       converter = TargetPythonVersionConverter.class,
-      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+      documentationCategory = OptionDocumentationCategory.OUTPUT_PARAMETERS,
       effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS, OptionEffectTag.AFFECTS_OUTPUTS},
-      help = "No-op, will be removed soon.")
+      help =
+          "Deprecated alias for `--python_version`. Disabled by "
+              + "`--incompatible_remove_old_python_version_api`.")
   public PythonVersion forcePython;
 
   private static final OptionDefinition FORCE_PYTHON_DEFINITION =
@@ -314,12 +322,14 @@ public PythonVersion getDefaultPythonVersion() {
   /**
    * Returns the Python major version ({@code PY2} or {@code PY3}) that targets should be built for.
    *
-   * <p>The version is taken as the value of {@code --python_version} if not null, otherwise {@link
-   * #getDefaultPythonVersion}.
+   * <p>The version is taken as the value of {@code --python_version} if not null, otherwise {@code
+   * --force_python} if not null, otherwise {@link #getDefaultPythonVersion}.
    */
   public PythonVersion getPythonVersion() {
     if (pythonVersion != null) {
       return pythonVersion;
+    } else if (forcePython != null) {
+      return forcePython;
     } else {
       return getDefaultPythonVersion();
     }
@@ -333,10 +343,10 @@ public PythonVersion getPythonVersion() {
    * different from the existing one.
    *
    * <p>Under the old semantics ({@link #incompatibleAllowPythonVersionTransitions} is false),
-   * version transitions are not allowed once the version has already been set ({@link
-   * #pythonVersion} is non-null). Due to a historical bug, it is also not allowed to transition the
-   * version to the hard-coded default value. Under these constraints, there is only one transition
-   * possible, from null to the non-default value, and it is never a no-op.
+   * version transitions are not allowed once the version has already been set ({@link #forcePython}
+   * or {@link #pythonVersion} is non-null). Due to a historical bug, it is also not allowed to
+   * transition the version to the hard-coded default value. Under these constraints, there is only
+   * one transition possible, from null to the non-default value, and it is never a no-op.
    *
    * @throws IllegalArgumentException if {@code version} is not {@code PY2} or {@code PY3}
    */
@@ -345,7 +355,7 @@ public boolean canTransitionPythonVersion(PythonVersion version) {
     if (incompatibleAllowPythonVersionTransitions) {
       return !version.equals(getPythonVersion());
     } else {
-      boolean currentlyUnset = pythonVersion == null;
+      boolean currentlyUnset = forcePython == null && pythonVersion == null;
       boolean transitioningToNonDefault = !version.equals(getDefaultPythonVersion());
       return currentlyUnset && transitioningToNonDefault;
     }
@@ -362,11 +372,22 @@ public boolean canTransitionPythonVersion(PythonVersion version) {
    * <p>If the old semantics are in effect ({@link #incompatibleAllowPythonVersionTransitions} is
    * false), after this method is called {@link #canTransitionPythonVersion} will return false.
    *
+   * <p>To help avoid breaking old-API {@code select()} expressions that check the value of {@code
+   * "force_python"}, both the old and new flags are updated even though {@code --python_version}
+   * takes precedence over {@code --force_python}.
+   *
    * @throws IllegalArgumentException if {@code version} is not {@code PY2} or {@code PY3}
    */
   public void setPythonVersion(PythonVersion version) {
     Preconditions.checkArgument(version.isTargetValue());
     this.pythonVersion = version;
+    // If the old version API is enabled, update forcePython for consistency. If the old API is
+    // disabled, don't update it because 1) no one can read it anyway, and 2) updating it during
+    // normalization would cause analysis-time validation of the flag to spuriously fail (it'd think
+    // the user set the flag).
+    if (!incompatibleRemoveOldPythonVersionApi) {
+      this.forcePython = version;
+    }
   }
 
   @Override
@@ -395,7 +416,7 @@ public FragmentOptions getHost() {
   public FragmentOptions getNormalized() {
     // Under the new version semantics, we want to ensure that options with "null" physical default
     // values are normalized, to avoid #7808. We don't want to normalize with the old version
-    // semantics because that breaks backwards compatibility.
+    // semantics because that breaks backwards compatibility (--force_python would always be on).
     PythonOptions newOptions = (PythonOptions) clone();
     if (incompatibleAllowPythonVersionTransitions) {
       newOptions.setPythonVersion(newOptions.getPythonVersion());

dataset/GitHub_Java/bazelbuild.bazel/src/test/java/com/google/devtools/build/lib/bazel/rules/python/BazelPyBinaryConfiguredTargetTest.java

@@ -387,8 +387,7 @@ public void explicitInitPy_CanBeGloballyEnabled() throws Exception {
             "    srcs = ['foo.py'],",
             ")"));
     useConfiguration("--incompatible_default_to_explicit_init_py=true");
-    assertThat(getDefaultRunfiles(getConfiguredTarget("//pkg:foo")).getEmptyFilenames().toList())
-        .isEmpty();
+    assertThat(getDefaultRunfiles(getConfiguredTarget("//pkg:foo")).getEmptyFilenames()).isEmpty();
   }
 
   @Test
@@ -402,7 +401,7 @@ public void explicitInitPy_CanBeSelectivelyDisabled() throws Exception {
             "    legacy_create_init = True,",
             ")"));
     useConfiguration("--incompatible_default_to_explicit_init_py=true");
-    assertThat(getDefaultRunfiles(getConfiguredTarget("//pkg:foo")).getEmptyFilenames().toList())
+    assertThat(getDefaultRunfiles(getConfiguredTarget("//pkg:foo")).getEmptyFilenames())
         .containsExactly("pkg/__init__.py");
   }
 
@@ -416,7 +415,7 @@ public void explicitInitPy_CanBeGloballyDisabled() throws Exception {
             "    srcs = ['foo.py'],",
             ")"));
     useConfiguration("--incompatible_default_to_explicit_init_py=false");
-    assertThat(getDefaultRunfiles(getConfiguredTarget("//pkg:foo")).getEmptyFilenames().toList())
+    assertThat(getDefaultRunfiles(getConfiguredTarget("//pkg:foo")).getEmptyFilenames())
         .containsExactly("pkg/__init__.py");
   }
 
@@ -431,7 +430,6 @@ public void explicitInitPy_CanBeSelectivelyEnabled() throws Exception {
             "    legacy_create_init = False,",
             ")"));
     useConfiguration("--incompatible_default_to_explicit_init_py=false");
-    assertThat(getDefaultRunfiles(getConfiguredTarget("//pkg:foo")).getEmptyFilenames().toList())
-        .isEmpty();
+    assertThat(getDefaultRunfiles(getConfiguredTarget("//pkg:foo")).getEmptyFilenames()).isEmpty();
   }
 }