Allow hyphens in Python package names

- Push policy decision on hyphens into PythonSemantics
- Revert PyCommon#validatePackageName() to non-static, to match other validation methods. (Static is more important for the initialization functions called from the constructor, to enforce that any init ordering dependencies are explicit.)

Fixes #9171.

RELNOTES: py_binary now tolerates package paths that contain hyphens ('-'). Note that such paths might not be importable from within Python code.
PiperOrigin-RevId: 340484250

src/main/java/com/google/devtools/build/lib/bazel/rules/python/BazelPythonSemantics.java

@@ -89,6 +89,11 @@ public String getSrcsVersionDocURL() {
   public void validate(RuleContext ruleContext, PyCommon common) {
   }
 
+  @Override
+  public boolean prohibitHyphensInPackagePaths() {
+    return false;
+  }
+
   @Override
   public void collectRunfilesForBinary(
       RuleContext ruleContext, Runfiles.Builder builder, PyCommon common, CcInfo ccInfo) {

src/main/java/com/google/devtools/build/lib/rules/python/PyCommon.java

@@ -218,7 +218,7 @@ public PyCommon(
     this.transitivePythonSources = initTransitivePythonSources(ruleContext);
     this.directPythonSources =
         initAndMaybeValidateDirectPythonSources(
-            ruleContext, /*validate=*/ validatePackageAndSources);
+            ruleContext, semantics, /*validate=*/ validatePackageAndSources);
     this.usesSharedLibraries = initUsesSharedLibraries(ruleContext);
     this.imports = initImports(ruleContext, semantics);
     this.hasPy2OnlySources = initHasPy2OnlySources(ruleContext, this.sourcesVersion);
@@ -229,7 +229,7 @@ public PyCommon(
     validateLegacyProviderNotUsedIfDisabled();
     maybeValidateLoadedFromBzl();
     if (validatePackageAndSources) {
-      validatePackageName(ruleContext);
+      validatePackageName();
     }
   }
 
@@ -282,13 +282,15 @@ private static void collectTransitivePythonSourcesFromDeps(
   }
 
   private static List<Artifact> initAndMaybeValidateDirectPythonSources(
-      RuleContext ruleContext, boolean validate) {
+      RuleContext ruleContext, PythonSemantics semantics, boolean validate) {
     List<Artifact> sourceFiles = new ArrayList<>();
     // TODO(bazel-team): Need to get the transitive deps closure, not just the sources of the rule.
     for (TransitiveInfoCollection src :
         ruleContext.getPrerequisitesIf("srcs", FileProvider.class)) {
       // Make sure that none of the sources contain hyphens.
-      if (validate && Util.containsHyphen(src.getLabel().getPackageFragment())) {
+      if (validate
+          && semantics.prohibitHyphensInPackagePaths()
+          && Util.containsHyphen(src.getLabel().getPackageFragment())) {
         ruleContext.attributeError(
             "srcs", src.getLabel() + ": paths to Python packages may not contain '-'");
       }
@@ -613,8 +615,9 @@ private void maybeValidateLoadedFromBzl() {
   }
 
   /** Checks that the package name of this Python rule does not contain a '-'. */
-  private static void validatePackageName(RuleContext ruleContext) {
-    if (Util.containsHyphen(ruleContext.getLabel().getPackageFragment())) {
+  private void validatePackageName() {
+    if (semantics.prohibitHyphensInPackagePaths()
+        && Util.containsHyphen(ruleContext.getLabel().getPackageFragment())) {
       ruleContext.ruleError("paths to Python packages may not contain '-'");
     }
   }

src/main/java/com/google/devtools/build/lib/rules/python/PythonSemantics.java

@@ -42,6 +42,12 @@ public interface PythonSemantics {
    */
   void validate(RuleContext ruleContext, PyCommon common);
 
+  /**
+   * Returns whether we are prohibiting hyphen ('-') characters in the package paths of Python
+   * targets and source files.
+   */
+  boolean prohibitHyphensInPackagePaths();
+
   /**
    * Extends for the default and data runfiles of {@code py_binary} and {@code py_test} rules with
    * custom elements.
@@ -61,14 +67,10 @@ void collectDefaultRunfilesForBinary(
   /** Collects a rule's default runfiles. */
   void collectDefaultRunfiles(RuleContext ruleContext, Runfiles.Builder builder);
 
-  /**
-   * Returns the coverage instrumentation specification to be used in Python rules.
-   */
+  /** Returns the coverage instrumentation specification to be used in Python rules. */
   InstrumentationSpec getCoverageInstrumentationSpec();
 
-  /**
-   * Utility function to compile multiple .py files to .pyc files, if required.
-   */
+  /** Utility function to compile multiple .py files to .pyc files, if required. */
   Collection<Artifact> precompiledPythonFiles(
       RuleContext ruleContext, Collection<Artifact> sources, PyCommon common);
 

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

@@ -436,33 +436,29 @@ public void explicitInitPy_CanBeSelectivelyEnabled() throws Exception {
   }
 
   @Test
-  public void packageNameCannotHaveHyphen() throws Exception {
-    checkError(
-        "pkg-hyphenated",
-        "foo",
-        // error:
-        "paths to Python packages may not contain '-'",
-        // build file:
+  public void packageNameCanHaveHyphen() throws Exception {
+    scratch.file(
+        "pkg-hyphenated/BUILD", //
         "py_binary(",
         "    name = 'foo',",
         "    srcs = ['foo.py'],",
         ")");
+    assertThat(getConfiguredTarget("//pkg-hyphenated:foo")).isNotNull();
+    assertNoEvents();
   }
 
   @Test
-  public void srcsPackageNameCannotHaveHyphen() throws Exception {
+  public void srcsPackageNameCanHaveHyphen() throws Exception {
     scratch.file(
         "pkg-hyphenated/BUILD", //
         "exports_files(['bar.py'])");
-    checkError(
-        "otherpkg",
-        "foo",
-        // error:
-        "paths to Python packages may not contain '-'",
-        // build file:
+    scratch.file(
+        "otherpkg/BUILD", //
         "py_binary(",
         "    name = 'foo',",
         "    srcs = ['foo.py', '//pkg-hyphenated:bar.py'],",
         ")");
+    assertThat(getConfiguredTarget("//otherpkg:foo")).isNotNull();
+    assertNoEvents();
   }
 }