Consider RCs equivalent to release for bazel_compatibility

We want `bazel_compatibiliy = [">=6.4.0"]` to match `6.4.0rc1` so that release candidates are indistinguishable from the actual release via Bazel version compatibility requirements. This allows more realistic testing of releases via RCs without having users to rely on hacks such as `bazel_compatibility = [">=6.3.9999"]`.

Along the way change the error message on incompatibility to include the standard module key identifier, which is `<root>` for the root module instead of `<name>@<version>`, both of which can be empty.

Closes #19678.

PiperOrigin-RevId: 569982709
Change-Id: I7dce89ac1c62c1539d71704f048dca65232c119c

src/main/java/com/google/devtools/build/lib/bazel/BazelVersion.java

@@ -33,8 +33,8 @@
  *
  * <ul>
  *   <li>{RELEASE} is a sequence of decimal numbers separated by dots;
- *   <li>{SUFFIX} could be: {@code -pre.*}, {@code rc\d+}, or any other string (which compares equal
- *       to SUFFIX is absent)
+ *   <li>{SUFFIX} could be: {@code -pre.*}, or any other string (which compares equal to SUFFIX
+ *       being absent)
  * </ul>
  */
 @AutoValue
@@ -52,9 +52,9 @@ public abstract class BazelVersion {
   /** Returns the original version string. */
   public abstract String getOriginal();
 
-  /** Whether this is a prerelease or a release candidate */
-  boolean isPrereleaseOrCandidate() {
-    return getSuffix().startsWith("-pre") || getSuffix().startsWith("rc");
+  /** Whether this is a prerelease */
+  boolean isPrerelease() {
+    return getSuffix().startsWith("-pre");
   }
 
   /** Parses a version string into a {@link BazelVersion} object. */
@@ -86,7 +86,7 @@ public boolean satisfiesCompatibility(String compatVersion) {
     int result =
         Objects.compare(
             getRelease(), compatSplit, lexicographical(Comparator.<Integer>naturalOrder()));
-    if (result == 0 && isPrereleaseOrCandidate()) {
+    if (result == 0 && isPrerelease()) {
       result = -1;
     }
 

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/BazelModuleResolutionFunction.java

@@ -208,12 +208,8 @@ public static void checkBazelCompatibility(
         if (!curVersion.satisfiesCompatibility(compatVersion)) {
           String message =
               String.format(
-                  "Bazel version %s is not compatible with module \"%s@%s\" (bazel_compatibility:"
-                      + " %s)",
-                  curVersion.getOriginal(),
-                  module.getName(),
-                  module.getVersion().getOriginal(),
-                  module.getBazelCompatibility());
+                  "Bazel version %s is not compatible with module \"%s\" (bazel_compatibility: %s)",
+                  curVersion.getOriginal(), module.getKey(), module.getBazelCompatibility());
 
           if (mode == BazelCompatibilityMode.WARNING) {
             eventHandler.handle(Event.warn(message));

src/test/java/com/google/devtools/build/lib/bazel/bzlmod/BazelModuleResolutionFunctionTest.java

@@ -162,7 +162,7 @@ public void testSimpleBazelCompatibilityFailure() throws Exception {
 
     assertThat(result.hasError()).isTrue();
     assertContainsEvent(
-        "Bazel version 5.1.4 is not compatible with module \"[email protected]\" (bazel_compatibility:"
+        "Bazel version 5.1.4 is not compatible with module \"<root>\" (bazel_compatibility:"
             + " [>5.1.0, <5.1.4])");
   }
 
@@ -180,7 +180,7 @@ public void testBazelCompatibilityWarning() throws Exception {
 
     assertThat(result.hasError()).isFalse();
     assertContainsEvent(
-        "Bazel version 5.1.4 is not compatible with module \"[email protected]\" (bazel_compatibility:"
+        "Bazel version 5.1.4 is not compatible with module \"<root>\" (bazel_compatibility:"
             + " [>5.1.0, <5.1.4])");
   }
 
@@ -198,7 +198,7 @@ public void testDisablingBazelCompatibility() throws Exception {
 
     assertThat(result.hasError()).isFalse();
     assertDoesNotContainEvent(
-        "Bazel version 5.1.4 is not compatible with module \"[email protected]\" (bazel_compatibility:"
+        "Bazel version 5.1.4 is not compatible with module \"<root>\" (bazel_compatibility:"
             + " [>5.1.0, <5.1.4])");
   }
 
@@ -227,6 +227,36 @@ public void testBazelCompatibilityFailure() throws Exception {
             + " [<=5.1.4, -5.1.2])");
   }
 
+  @Test
+  public void testRcIsCompatibleWithReleaseRequirement() throws Exception {
+    scratch.file(
+        rootDirectory.getRelative("MODULE.bazel").getPathString(),
+        "module(name='mod', version='1.0', bazel_compatibility=['>=6.4.0'])");
+
+    embedBazelVersion("6.4.0rc1");
+    EvaluationResult<BazelModuleResolutionValue> result =
+        evaluator.evaluate(ImmutableList.of(BazelModuleResolutionValue.KEY), evaluationContext);
+
+    assertThat(result.hasError()).isFalse();
+  }
+
+  @Test
+  public void testPrereleaseIsNotCompatibleWithReleaseRequirement() throws Exception {
+    scratch.file(
+        rootDirectory.getRelative("MODULE.bazel").getPathString(),
+        "module(name='mod', version='1.0', bazel_compatibility=['>=6.4.0'])");
+
+    embedBazelVersion("6.4.0-pre-1");
+    reporter.removeHandler(failFastHandler);
+    EvaluationResult<BazelModuleResolutionValue> result =
+        evaluator.evaluate(ImmutableList.of(BazelModuleResolutionValue.KEY), evaluationContext);
+
+    assertThat(result.hasError()).isTrue();
+    assertContainsEvent(
+        "Bazel version 6.4.0-pre-1 is not compatible with module \"<root>\" (bazel_compatibility:"
+            + " [>=6.4.0])");
+  }
+
   private void embedBazelVersion(String version) {
     // Double-get version-info to determine if it's the cached instance or not, and if not cache it.
     BlazeVersionInfo blazeInfo1 = BlazeVersionInfo.instance();