Work around apparent javadoc parsing limitation with empty comments

Fixes google#1981 PiperOrigin-RevId: 350677284
HubSpot · Jan 15, 2021 · 3445562 · 3445562
1 parent b378657
commit 3445562
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Showing 2 changed files with 19 additions and 12 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/javadoc/Utils.java b/core/src/main/java/com/google/errorprone/bugpatterns/javadoc/Utils.java
@@ -20,6 +20,7 @@
 
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.doctree.DocCommentTree;
 import com.sun.source.doctree.DocTree;
 import com.sun.source.tree.CompilationUnitTree;
@@ -87,6 +88,11 @@ static int getEndPosition(DocTree docTree, VisitorState state) {
   static DiagnosticPosition diagnosticPosition(DocTreePath path, VisitorState state) {
     int startPosition = getStartPosition(path.getLeaf(), state);
     Tree tree = path.getTreePath().getLeaf();
+    if (startPosition == Position.NOPOS) {
+      // javac doesn't seem to store positions for e.g. trivial empty javadoc like `/** */`
+      // see: https://github.com/google/error-prone/issues/1981
+      startPosition = ASTHelpers.getStartPosition(tree);
+    }
     return getDiagnosticPosition(startPosition, tree);
   }
 

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/javadoc/MissingSummaryTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/javadoc/MissingSummaryTest.java
@@ -137,18 +137,6 @@ public void negative() {
         .doTest();
   }
 
-  @Test
-  public void negativeEmpty() {
-    helper
-        .addSourceLines(
-            "Test.java", //
-            "interface Test {",
-            "  /** */",
-            "  int test();",
-            "}")
-        .doTest();
-  }
-
   @Test
   public void negativeAnnotations() {
     helper
@@ -222,4 +210,17 @@ public void emptyReturn() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void emptyComment() {
+    helper
+        .addSourceLines(
+            "Test.java", //
+            "package test;",
+            "/** */",
+            "// BUG: Diagnostic contains: summary line is required",
+            "public class Test {",
+            "}")
+        .doTest();
+  }
 }