Run the string wrapping pass to a fixed point

From palantir#1784 by Zayan Khan, which fixes
palantir#1343 (#34 here). The indentation
StringWrapper picks for a text block is derived from the layout around
it, but the same pass can move that layout, so one round is not always
a fixed point. In the nested array initialisers of
palantir#1343 the second text block moved four
columns on a second run, so a file that --replace had just written was
reported by --set-exit-if-changed. wrap already recomputed its
replacements after reformatting, twice; it now repeats the pass while
it keeps changing the source, up to MAX_ROUNDS = 5.

Adapted while bringing it over: paths moved from palantir-java-format/
to open-java-format/, and the changelog entry left out.

Of the 15,747 files of the JDK 21 sources one formats differently,
java/lang/Module.java, whose text block argument the old code moved
again on a second run; one run now gives that second result. Formatting
the sources takes no longer.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: 2 people

open-java-format/src/main/java/com/palantir/javaformat/java/StringWrapper.java

@@ -56,8 +56,25 @@ public final class StringWrapper {
 
     public static final String TEXT_BLOCK_DELIMITER = "\"\"\"";
 
+    /**
+     * How many times {@link #wrapOnce} may be re-run while it is still changing the source. The indentation chosen
+     * for a text block is derived from the layout around it, which this pass can itself move, so a single round is
+     * not always a fixed point and the formatter would not be idempotent. See
+     * <a href="https://github.com/palantir/open-java-format/issues/1343">#1343</a>.
+     */
+    private static final int MAX_ROUNDS = 5;
+
     /** Reflows string literals in the given Java source code that extend past the given column limit. */
     static String wrap(final int columnLimit, String input, Formatter formatter) throws FormatterException {
+        String result = wrapOnce(columnLimit, input, formatter);
+        for (int round = 1; round < MAX_ROUNDS && !result.equals(input); round++) {
+            input = result;
+            result = wrapOnce(columnLimit, input, formatter);
+        }
+        return result;
+    }
+
+    private static String wrapOnce(final int columnLimit, String input, Formatter formatter) throws FormatterException {
         if (!needWrapping(columnLimit, input)) {
             // fast path
             return input;

open-java-format/src/test/resources/com/palantir/javaformat/java/testdata/palantir-issue-1343-text-block-indent-stable.input

@@ -0,0 +1,35 @@
+class PalantirIssue1343TextBlockIndentStable {
+    String[][] withCommentFirstLine = {
+        {
+            """
+            // tmp fix
+            @Deprecated
+            class Test {}
+            """
+        },
+        {
+            """
+
+            @Deprecated
+            class Test {}
+            """
+        }
+    };
+
+    String[][] blankLineInTheMiddle = {
+        {
+            """
+            import java.util.List;
+
+            @Deprecated
+            class Test {}
+            """
+        },
+        {
+            """
+
+            class Test {}
+            """
+        }
+    };
+}

open-java-format/src/test/resources/com/palantir/javaformat/java/testdata/palantir-issue-1343-text-block-indent-stable.output

@@ -0,0 +1,21 @@
+class PalantirIssue1343TextBlockIndentStable {
+    String[][] withCommentFirstLine = {{"""
+        // tmp fix
+        @Deprecated
+        class Test {}
+        """}, {"""
+
+            @Deprecated
+            class Test {}
+            """}};
+
+    String[][] blankLineInTheMiddle = {{"""
+        import java.util.List;
+
+        @Deprecated
+        class Test {}
+        """}, {"""
+
+            class Test {}
+            """}};
+}