Add flag --experimental_enable_repo_mapping to gate usage of repo_mapping functionality in WORKSPACE rules.

RELNOTES: None
PiperOrigin-RevId: 199332092

src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsCodec.java

diff --git a/src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsCodec.java b/src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsCodec.java
index 758eb39..c1d6dac 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsCodec.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsCodec.java
@@ -43,6 +43,7 @@
       SerializationContext context, SkylarkSemantics semantics, CodedOutputStream codedOut)
       throws SerializationException, IOException {
     // <== Add new options here in alphabetic order ==>
+    codedOut.writeBoolNoTag(semantics.experimentalEnableRepoMapping());
     codedOut.writeBoolNoTag(semantics.incompatibleBzlDisallowLoadAfterStatement());
     codedOut.writeBoolNoTag(semantics.incompatibleDepsetIsNotIterable());
     codedOut.writeBoolNoTag(semantics.incompatibleDepsetUnion());
@@ -67,6 +68,7 @@
     SkylarkSemantics.Builder builder = SkylarkSemantics.builder();
 
     // <== Add new options here in alphabetic order ==>
+    builder.experimentalEnableRepoMapping(codedIn.readBool());
     builder.incompatibleBzlDisallowLoadAfterStatement(codedIn.readBool());
     builder.incompatibleDepsetIsNotIterable(codedIn.readBool());
     builder.incompatibleDepsetUnion(codedIn.readBool());

src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsOptions.java

diff --git a/src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsOptions.java b/src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsOptions.java
index 0a9a9eb..d77f5c9 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/SkylarkSemanticsOptions.java
@@ -60,6 +60,15 @@
   // <== Add new options here in alphabetic order ==>
 
   @Option(
+      name = "experimental_enable_repo_mapping",
+      defaultValue = "false",
+      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+      effectTags = OptionEffectTag.BUILD_FILE_SEMANTICS,
+      help = "If set to true, enables the use of the `repo_mapping` attribute in WORKSPACE files."
+  )
+  public boolean experimentalEnableRepoMapping;
+
+  @Option(
     name = "incompatible_bzl_disallow_load_after_statement",
     defaultValue = "false",
     documentationCategory = OptionDocumentationCategory.UNCATEGORIZED,
@@ -288,6 +297,7 @@
   public SkylarkSemantics toSkylarkSemantics() {
     return SkylarkSemantics.builder()
         // <== Add new options here in alphabetic order ==>
+        .experimentalEnableRepoMapping(experimentalEnableRepoMapping)
         .incompatibleBzlDisallowLoadAfterStatement(incompatibleBzlDisallowLoadAfterStatement)
         .incompatibleDepsetIsNotIterable(incompatibleDepsetIsNotIterable)
         .incompatibleDepsetUnion(incompatibleDepsetUnion)

src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
index 1a5cc17..ac556e2 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
@@ -39,6 +39,8 @@
       AutoValue_SkylarkSemantics.class;
 
   // <== Add new options here in alphabetic order ==>
+  public abstract boolean experimentalEnableRepoMapping();
+
   public abstract boolean incompatibleBzlDisallowLoadAfterStatement();
 
   public abstract boolean incompatibleDepsetIsNotIterable();
@@ -86,6 +88,7 @@
   public static final SkylarkSemantics DEFAULT_SEMANTICS =
       builder()
           // <== Add new options here in alphabetic order ==>
+          .experimentalEnableRepoMapping(false)
           .incompatibleBzlDisallowLoadAfterStatement(false)
           .incompatibleDepsetIsNotIterable(false)
           .incompatibleDepsetUnion(false)
@@ -109,6 +112,8 @@
   public abstract static class Builder {
 
     // <== Add new options here in alphabetic order ==>
+    public abstract Builder experimentalEnableRepoMapping(boolean value);
+
     public abstract Builder incompatibleBzlDisallowLoadAfterStatement(boolean value);
 
     public abstract Builder incompatibleDepsetIsNotIterable(boolean value);

src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java

diff --git a/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java b/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
index 0edd71e..8d6e217 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
@@ -119,6 +119,7 @@
   private static SkylarkSemanticsOptions buildRandomOptions(Random rand) throws Exception {
     return parseOptions(
         // <== Add new options here in alphabetic order ==>
+        "--experimental_enable_repo_mapping=" + rand.nextBoolean(),
         "--incompatible_bzl_disallow_load_after_statement=" + rand.nextBoolean(),
         "--incompatible_depset_is_not_iterable=" + rand.nextBoolean(),
         "--incompatible_depset_union=" + rand.nextBoolean(),
@@ -144,6 +145,7 @@
   private static SkylarkSemantics buildRandomSemantics(Random rand) {
     return SkylarkSemantics.builder()
         // <== Add new options here in alphabetic order ==>
+        .experimentalEnableRepoMapping(rand.nextBoolean())
         .incompatibleBzlDisallowLoadAfterStatement(rand.nextBoolean())
         .incompatibleDepsetIsNotIterable(rand.nextBoolean())
         .incompatibleDepsetUnion(rand.nextBoolean())