Add support in ErrorProne for a new ThreadSafeTypeParamerter annota…

…tion that is replacing `ThreadSafe.TypeParameter`.

A follow-up CL will actually create the annotation once ErrorProne has this CL released to avoid premature dependencies on the new annotation.

This is the first step in open sourcing the threadsafe equivalent of `ImmutableTypeParameter`. After this an LSC will be performed to replace all usages of `ThreadSafe.TypeParameter` with `ThreadSafeTypeParameter` after which and remaining references to the former (e.g. in messages) will be removed.

PiperOrigin-RevId: 651816128

core/src/main/java/com/google/errorprone/bugpatterns/threadsafety/ThreadSafeChecker.java

@@ -99,10 +99,10 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
 
   @Override
   public Description matchNewClass(NewClassTree tree, VisitorState state) {
-    // check instantiations of `@ThreadSafe.TypeParameter`s in generic constructor invocations
+    // check instantiations of `@ThreadSafeTypeParameter`s in generic constructor invocations
     checkInvocation(
         tree, ((JCNewClass) tree).constructorType, state, ((JCNewClass) tree).constructor);
-    // check instantiations of `@ThreadSafe.TypeParameter`s in class constructor invocations
+    // check instantiations of `@ThreadSafeTypeParameter`s in class constructor invocations
     ThreadSafeAnalysis analysis = new ThreadSafeAnalysis(this, state, wellKnownThreadSafety);
     Violation info =
         analysis.checkInstantiation(
@@ -137,6 +137,7 @@ public Description matchTypeParameter(TypeParameterTree tree, VisitorState state
     ThreadSafeAnalysis analysis = new ThreadSafeAnalysis(this, state, wellKnownThreadSafety);
     if (analysis.hasThreadSafeTypeParameterAnnotation((TypeVariableSymbol) sym)) {
       if (analysis.getThreadSafeAnnotation(sym.owner, state) == null) {
+        // TODO: b/324092874 -- Update this message to use the new annotation name.
         return buildDescription(tree)
             .setMessage("@ThreadSafe.TypeParameter is only supported on threadsafe classes")
             .build();
@@ -198,6 +199,7 @@ public Description matchClass(ClassTree tree, VisitorState state) {
             .map(Entry::getKey)
             .collect(toImmutableSet());
     if (!threadSafeAndContainer.isEmpty()) {
+      // TODO: b/324092874 -- Update this message to use the new annotation name.
       return buildDescription(tree)
           .setMessage(
               String.format(

core/src/test/java/com/google/errorprone/bugpatterns/threadsafety/ThreadSafeCheckerTest.java

@@ -41,7 +41,14 @@
 public class ThreadSafeCheckerTest {
 
   private final CompilationTestHelper compilationHelper =
-      CompilationTestHelper.newInstance(ThreadSafeChecker.class, getClass());
+      CompilationTestHelper.newInstance(ThreadSafeChecker.class, getClass())
+          // TODO: b/339025111 - Remove this once ThreadSafeTypeParameter actually exists.
+          .addSourceLines(
+              "ThreadSafeTypeParameter.java",
+              "package com.google.errorprone.annotations;",
+              "@java.lang.annotation.Target(java.lang.annotation.ElementType.TYPE_PARAMETER)",
+              "@java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.RUNTIME)",
+              "public @interface ThreadSafeTypeParameter {}");
 
   private final BugCheckerRefactoringTestHelper refactoringHelper =
       BugCheckerRefactoringTestHelper.newInstance(ThreadSafeChecker.class, getClass());
@@ -1001,6 +1008,16 @@ public void knownThreadSafeFlag() {
         .doTest();
   }
 
+  // TODO: b/324092874 - Remove this test once ThreadSafe.TypeParameter is removed.
+
+  // TODO: b/324092874 - Remove this test once ThreadSafe.TypeParameter is removed.
+
+  // TODO: b/324092874 - Remove this test once ThreadSafe.TypeParameter is removed.
+
+  // TODO: b/324092874 - Remove this test once ThreadSafe.TypeParameter is removed.
+
+  // TODO: b/324092874 - Remove this test once ThreadSafe.TypeParameter is removed.
+
   @Test
   public void annotatedClassType() {
     compilationHelper
@@ -1015,7 +1032,16 @@ public void annotatedClassType() {
         .doTest();
   }
 
+  // TODO: b/324092874 - Remove this test once ThreadSafe.TypeParameter is removed.
+
   // Regression test for b/117937500
+  // TODO: b/324092874 - Remove this test once ThreadSafe.TypeParameter is removed.
+
+  // Regression test for b/117937500
+
+  // javac does not instantiate type variables when they are not used for target typing, so we
+  // cannot check whether their instantiations are thread-safe.
+  // TODO: b/324092874 - Remove this test once ThreadSafe.TypeParameter is removed.
 
   // javac does not instantiate type variables when they are not used for target typing, so we
   // cannot check whether their instantiations are thread-safe.