More extensible approach

refaster-runner/src/main/java/tech/picnic/errorprone/refaster/runner/CodeTransformers.java

@@ -1,15 +1,21 @@
 package tech.picnic.errorprone.refaster.runner;
 
 import com.google.common.base.Suppliers;
+import com.google.common.collect.ImmutableClassToInstanceMap;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.reflect.ClassPath;
 import com.google.common.reflect.ClassPath.ResourceInfo;
 import com.google.errorprone.CodeTransformer;
+import com.google.errorprone.DescriptionListener;
+import com.google.errorprone.matchers.Description;
+import com.sun.source.util.TreePath;
+import com.sun.tools.javac.util.Context;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.ObjectInputStream;
 import java.io.UncheckedIOException;
+import java.lang.annotation.Annotation;
 import java.util.NoSuchElementException;
 import java.util.Optional;
 import java.util.function.Supplier;
@@ -106,4 +112,44 @@ public final class CodeTransformers {
       throw new IllegalStateException("Can't load `CodeTransformer` from " + resource, e);
     }
   }
+
+  // XXX: Move to separate file?
+  // XXX: Can we find a better class name?
+  private static final class CodeTransformerDescriptionAdapter implements CodeTransformer {
+    private final String name;
+    private final CodeTransformer delegate;
+
+    private CodeTransformerDescriptionAdapter(String name, CodeTransformer delegate) {
+      this.name = name;
+      this.delegate = delegate;
+    }
+
+    @Override
+    public void apply(TreePath path, Context context, DescriptionListener listener) {
+      delegate.apply(
+          path, context, description -> listener.onDescribed(augmentDescription(description)));
+    }
+
+    @Override
+    public ImmutableClassToInstanceMap<Annotation> annotations() {
+      return delegate.annotations();
+    }
+
+    private Description augmentDescription(Description description) {
+      // XXX: Make this configurable based on a Refaster annotation. (E.g. by allowing users to
+      // specify an optional URL pattern.)
+      // XXX: Replace only the first `$`.
+      // XXX: Review URL format. Currently produced format:
+      // https://error-prone.picnic.tech/refastertemplates/OptionalTemplates#OptionalOrElseThrow
+      // XXX: Test this.
+      return Description.builder(
+              description.position,
+              description.checkName,
+              "https://error-prone.picnic.tech/refastertemplates/" + name.replace('$', '#'),
+              description.severity,
+              "Refactoring opportunity")
+          .addAllFixes(description.fixes)
+          .build();
+    }
+  }
 }

refaster-runner/src/main/java/tech/picnic/errorprone/refaster/runner/Refaster.java

@@ -142,7 +142,7 @@ public final class Refaster extends BugChecker implements CompilationUnitTreeMat
       ImmutableRangeSet<Integer> ranges = getReplacementRanges(description, endPositions);
       if (ranges.asRanges().stream().noneMatch(replacedSections::intersects)) {
         /* This suggested fix does not overlap with any ("larger") replacement seen until now. Apply it. */
-        state.reportMatch(withCustomLink(description));
+        state.reportMatch(description);
         replacedSections.addAll(ranges);
       }
     }