Merge pull request #77 from openjavaformat/comment-before-lambda-close-parens

Do not inline a lambda body whose closing paren carries a comment

Author: abashev

open-java-format/src/main/java/com/palantir/javaformat/doc/Level.java

@@ -339,9 +339,19 @@ private Optional<State> tryInlinePrefixOntoCurrentLine(
 
         // Add the width of tokens, breaks before the lastLevel. We must always have space for
         // these.
-        List<Doc> leadingDocs = docs.subList(0, docs.indexOf(lastLevel));
+        int lastLevelIndex = docs.indexOf(lastLevel);
+        List<Doc> leadingDocs = docs.subList(0, lastLevelIndex);
         float leadingWidth = getWidth(leadingDocs);
 
+        // A forced break after the lastLevel, such as the ones around a // comment that sits before this level's
+        // closing token, cannot be laid out flat by tryToLayOutLevelOnOneLine: the comment would swallow every token
+        // after it on the line. Such a level breaks normally instead, as tryBreakInnerLevel refuses it for the same
+        // reason. (A forced break before the lastLevel makes leadingWidth infinite and fails the check below.)
+        List<Doc> trailingDocs = docs.subList(lastLevelIndex + 1, docs.size());
+        if (Float.isInfinite(getWidth(trailingDocs))) {
+            return Optional.empty();
+        }
+
         // Potentially add the width of prefixes we want to consider as part of the width that
         // must fit on the same line, so that we don't accidentally break prefixes when we could
         // have avoided doing so.
@@ -592,6 +602,9 @@ private static Optional<State> tryBreakInnerLevel_checkInner(
      * Mark breaks in this level as not broken, but lay out the inner levels normally, according to their own
      * {@link BreakBehaviour}. The resulting {@link State#mustBreak} will be true if this level did not fit on exactly
      * one line.
+     *
+     * <p>The callers make sure that none of this level's own breaks is forced: a forced break laid out flat would put
+     * the tokens after a {@code //} comment inside the comment.
      */
     private State tryToLayOutLevelOnOneLine(
             CommentsHelper commentsHelper,

open-java-format/src/test/resources/com/palantir/javaformat/java/testdata/ojf-issue-62-comment-before-lambda-close-parens.input

@@ -0,0 +1,24 @@
+import java.util.stream.IntStream;
+
+class Repro {
+    int find(Item[] items) {
+        return IntStream.range(0, items.length)
+                .filter(i -> (items[i].getName().equals("alpha") || items[i].getName().equals("beta")
+                        || items[i].getName().equals("gamma")
+                // || (items[i].getName().equals("delta") && items.length > i
+                // && items[i + 1].getName().equals("epsilon"))
+                )).findFirst().orElse(-1);
+    }
+
+    void plainCall() {
+        check(i -> (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(i) || bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(i)
+                // || c(i)
+                ));
+    }
+
+    void blockComment() {
+        check(i -> (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(i) || bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(i)
+                /* block */
+                ));
+    }
+}

open-java-format/src/test/resources/com/palantir/javaformat/java/testdata/ojf-issue-62-comment-before-lambda-close-parens.output

@@ -0,0 +1,32 @@
+import java.util.stream.IntStream;
+
+class Repro {
+    int find(Item[] items) {
+        return IntStream.range(0, items.length)
+                .filter(i ->
+                        (items[i].getName().equals("alpha")
+                                || items[i].getName().equals("beta")
+                                || items[i].getName().equals("gamma")
+                        // || (items[i].getName().equals("delta") && items.length > i
+                        // && items[i + 1].getName().equals("epsilon"))
+                        ))
+                .findFirst()
+                .orElse(-1);
+    }
+
+    void plainCall() {
+        check(i ->
+                (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(i)
+                        || bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(i)
+                // || c(i)
+                ));
+    }
+
+    void blockComment() {
+        check(i ->
+                (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(i)
+                        || bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(i)
+                /* block */
+                ));
+    }
+}