From d7e586657a31c61a3c8037a5697c26c2d6fb0071 Mon Sep 17 00:00:00 2001
From: ghm <ghm@google.com>
Date: Wed, 8 Jan 2020 01:57:34 -0800
Subject: [PATCH] MissingSummary: don't fail in the case that javac fails to
 provide an endpos for @see.

Fixes external #1444

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=288656035
---
 .../bugpatterns/javadoc/MissingSummary.java   | 24 ++++++++++++-------
 .../errorprone/bugpatterns/javadoc/Utils.java |  4 ++++
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/javadoc/MissingSummary.java b/core/src/main/java/com/google/errorprone/bugpatterns/javadoc/MissingSummary.java
index 6e7cb4ef7b8..74ae0c8efb9 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/javadoc/MissingSummary.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/javadoc/MissingSummary.java
@@ -149,16 +149,22 @@ private Description generateReturnFix(
 
   private Description generateSeeFix(DocTreePath docTreePath, SeeTree seeTree, VisitorState state) {
     int pos = ((DCDocComment) docTreePath.getDocComment()).comment.getSourcePos(0);
+    // javac fails to provide an endpos for @see sometimes; don't emit a fix in that case.
+    SuggestedFix replacement = Utils.replace(seeTree, "", state);
     SuggestedFix fix =
-        SuggestedFix.builder()
-            .merge(Utils.replace(seeTree, "", state))
-            .replace(
-                pos,
-                pos,
-                String.format(
-                    "See {@link %s}.\n",
-                    seeTree.getReference().stream().map(Object::toString).collect(joining(" "))))
-            .build();
+        replacement.isEmpty()
+            ? replacement
+            : SuggestedFix.builder()
+                .merge(replacement)
+                .replace(
+                    pos,
+                    pos,
+                    String.format(
+                        "See {@link %s}.\n",
+                        seeTree.getReference().stream()
+                            .map(Object::toString)
+                            .collect(joining(" "))))
+                .build();
     return buildDescription(diagnosticPosition(docTreePath, state))
         .setMessage(String.format(CONSIDER_USING_MESSAGE, "see"))
         .addFix(fix)
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
index 457c041f7e0..4465bed8ca0 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/javadoc/Utils.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/javadoc/Utils.java
@@ -32,6 +32,7 @@
 import com.sun.tools.javac.tree.JCTree;
 import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
+import com.sun.tools.javac.util.Position;
 import java.util.Optional;
 import javax.annotation.Nullable;
 
@@ -65,6 +66,9 @@ static SuggestedFix replace(DocTree docTree, String replacement, VisitorState st
     int startPos = getStartPosition(docTree, state);
     int endPos =
         (int) positions.getEndPosition(compilationUnitTree, getDocCommentTree(state), docTree);
+    if (endPos == Position.NOPOS) {
+      return SuggestedFix.builder().build();
+    }
     return SuggestedFix.replace(startPos, endPos, replacement);
   }