Java part of python nostamp mitigation support.

The purpose of this change is to modify py_binary building so that when binaries are built with the --nostamp flag, most stamp info is still suppressed, but the build _target_ is still stamped.

This change will bring py_binary targets into line with current behaviour in C++, Java, Go and Rust.

PiperOrigin-RevId: 682299016
Change-Id: If33314ca3daf6c9b68daca3e539f7493119ddebf

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

@@ -52,6 +52,9 @@ public class PythonConfiguration extends Fragment implements StarlarkValue {
   // TODO(brandjon): Remove this once migration to Python toolchains is complete.
   private final boolean useToolchains;
 
+  /* Whether to include the build label in unstamped builds. */
+  private final boolean includeLabelInLinkstamp;
+
   private final boolean defaultToExplicitInitPy;
   private final boolean disablePy2;
   @Nullable private final Label nativeRulesAllowlist;
@@ -70,6 +73,7 @@ public PythonConfiguration(BuildOptions buildOptions) {
     this.disablePy2 = pythonOptions.disablePy2;
     this.nativeRulesAllowlist = pythonOptions.nativeRulesAllowlist;
     this.disallowNativeRules = pythonOptions.disallowNativeRules;
+    this.includeLabelInLinkstamp = pythonOptions.includeLabelInPyBinariesLinkstamp;
   }
 
   @Override
@@ -199,4 +203,13 @@ public boolean getDisallowNativeRules() {
   public Label getNativeRulesAllowlist() {
     return nativeRulesAllowlist;
   }
+
+  /** Returns whether the build label is included in unstamped builds. */
+  @StarlarkMethod(
+      name = "include_label_in_linkstamp",
+      doc = "Whether the build label is included in unstamped builds.",
+      structField = true)
+  public boolean isIncludeLabelInLinkstamp() {
+    return includeLabelInLinkstamp;
+  }
 }

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

@@ -259,6 +259,14 @@ public String getTypeDescription() {
               + " more information and migration instructions.")
   public boolean disallowNativeRules;
 
+  @Option(
+      name = "experimental_py_binaries_include_label",
+      defaultValue = "false",
+      documentationCategory = OptionDocumentationCategory.OUTPUT_PARAMETERS,
+      effectTags = {OptionEffectTag.AFFECTS_OUTPUTS},
+      help = "py_binary targets include their label even when stamping is disabled.")
+  public boolean includeLabelInPyBinariesLinkstamp;
+
   // Helper field to store hostForcePython in exec configuration
   private PythonVersion defaultPythonVersion = null;