Issue #14689: Resolve Javadoc summary false positives

src/it/resources/com/google/checkstyle/test/chapter7javadoc/rule72thesummaryfragment/InputIncorrectSummaryJavaDocCheck.java

@@ -7,7 +7,7 @@
 class InputIncorrectSummaryJavaDocCheck {
 
     /**
-     * As of JDK 1.1, replaced by {@link #setBounds(int,int,int,int)}
+     * As of JDK 1.1, replaced by {@link #setBounds(int,int,int,int)}.
      */
     void foo3() {}
 

src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheck.java

@@ -21,6 +21,8 @@
 
 import java.util.Arrays;
 import java.util.BitSet;
+import java.util.Deque;
+import java.util.LinkedList;
 import java.util.Optional;
 import java.util.regex.Pattern;
 
@@ -218,13 +220,11 @@ private void validateUntaggedSummary(DetailNode ast) {
             log(ast.getLineNumber(), MSG_SUMMARY_JAVADOC_MISSING);
         }
         else if (!period.isEmpty()) {
-            final String firstSentence = getFirstSentence(ast);
-            final int endOfSentence = firstSentence.lastIndexOf(period);
-            if (!summaryDoc.contains(period)) {
+            final String firstSentence = getFirstSentence(ast, period);
+            if (!summaryDoc.contains(period) || firstSentence.isEmpty()) {
                 log(ast.getLineNumber(), MSG_SUMMARY_FIRST_SENTENCE);
             }
-            if (endOfSentence != -1
-                    && containsForbiddenFragment(firstSentence.substring(0, endOfSentence))) {
+            else if (containsForbiddenFragment(firstSentence)) {
                 log(ast.getLineNumber(), MSG_SUMMARY_JAVADOC);
             }
         }
@@ -579,28 +579,60 @@ private static String getStringInsideTag(String result, DetailNode detailNode) {
      * Finds and returns first sentence.
      *
      * @param ast Javadoc root node.
+     * @param period Period character.
      * @return first sentence.
      */
-    private static String getFirstSentence(DetailNode ast) {
+    private static String getFirstSentence(DetailNode ast, String period) {
+        final Deque<DetailNode> stack = new LinkedList<>();
+        stack.push(ast);
         final StringBuilder result = new StringBuilder(256);
-        final String periodSuffix = DEFAULT_PERIOD + ' ';
-        for (DetailNode child : ast.getChildren()) {
-            final String text;
-            if (child.getChildren().length == 0) {
-                text = child.getText();
+        boolean foundPeriod = false;
+        while (!stack.isEmpty()) {
+            final DetailNode node = stack.pop();
+            if (node.getChildren().length == 0) {
+                final String text = node.getText();
+                final int periodIndex = findEndingPeriod(text, period);
+                if (periodIndex >= 0) {
+                    foundPeriod = true;
+                    result.append(text, 0, periodIndex);
+                    break;
+                }
+                else {
+                    result.append(text);
+                }
             }
-            else {
-                text = getFirstSentence(child);
+            // Pushing last child first means it will be processed last
+            for (int childIndex = node.getChildren().length - 1; childIndex >= 0; childIndex--) {
+                stack.push(node.getChildren()[childIndex]);
             }
+        }
+        if (!foundPeriod) {
+            result.setLength(0);
+        }
+        return result.toString();
+    }
 
-            if (text.contains(periodSuffix)) {
-                result.append(text, 0, text.indexOf(periodSuffix) + 1);
+    /**
+     * Find position of an ending period in the text. Ignores any period not followed by
+     * whitespace.
+     *
+     * @param text text to search
+     * @param period period character
+     * @return position of period character, or -1 if there is no ending period
+     */
+    private static int findEndingPeriod(String text, String period) {
+        int periodIndex = text.indexOf(period);
+        while (periodIndex >= 0) {
+            final int afterPeriodIndex = periodIndex + period.length();
+            if (afterPeriodIndex >= text.length()
+                || Character.isWhitespace(text.charAt(afterPeriodIndex))) {
                 break;
             }
-
-            result.append(text);
+            else {
+                periodIndex = text.indexOf(period, afterPeriodIndex);
+            }
         }
-        return result.toString();
+        return periodIndex;
     }
 
 }

src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheckTest.java

@@ -113,6 +113,7 @@ public void testPeriod() throws Exception {
             "14: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
             "19: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
             "37: " + getCheckMessage(MSG_SUMMARY_MISSING_PERIOD),
+            "42: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
         };
 
         verifyWithInlineConfigParser(
@@ -230,12 +231,24 @@ public void testPeriodAtEnd() throws Exception {
             "33: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
             "40: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
             "60: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
+            "70: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
         };
 
         verifyWithInlineConfigParser(
                 getPath("InputSummaryJavadocPeriodAtEnd.java"), expected);
     }
 
+    @Test
+    public void testForbiddenFragmentRelativeToPeriod() throws Exception {
+        final String[] expected = {
+            "23: " + getCheckMessage(MSG_SUMMARY_JAVADOC),
+            "30: " + getCheckMessage(MSG_SUMMARY_JAVADOC),
+        };
+
+        verifyWithInlineConfigParser(
+                getPath("InputSummaryJavadocForbiddenFragmentRelativeToPeriod.java"), expected);
+    }
+
     @Test
     public void testHtmlFormatSummary() throws Exception {
         final String[] expected = {

src/test/resources/com/puppycrawl/tools/checkstyle/checks/javadoc/summaryjavadoc/InputSummaryJavadocForbiddenFragmentRelativeToPeriod.java

@@ -0,0 +1,35 @@
+/*
+SummaryJavadoc
+violateExecutionOnNonTightHtml = (default)false
+forbiddenSummaryFragments = ^$|fail-summary-fragment
+period = _
+
+
+*/
+
+package com.puppycrawl.tools.checkstyle.checks.javadoc.summaryjavadoc;
+
+public class InputSummaryJavadocForbiddenFragmentRelativeToPeriod {
+
+    /**
+     * Summary sentence on its own line_
+     * <p>
+     * Another sentence that is not part of the summary,
+     * so this should not matter: fail-summary-fragment_
+     */
+    void foo1() {}
+
+    // violation below 'Forbidden summary fragment.'
+    /**
+     * Summary sentence containing default period mentioning version 1.1, then ending with correct
+     * period after disallowed words, fail-summary-fragment_
+     */
+    void foo2() {}
+
+    // violation below 'Forbidden summary fragment.'
+    /**
+     * Summary sentence containing correct period mid_word, then ending with correct period after
+     * disallowed words, fail-summary-fragment_
+     */
+    void foo3() {}
+}

src/test/resources/com/puppycrawl/tools/checkstyle/checks/javadoc/summaryjavadoc/InputSummaryJavadocIncorrect.java

@@ -17,7 +17,7 @@
 class InputSummaryJavadocIncorrect {
 
     /**
-     * As of JDK 1.1, replaced by {@link #setBounds(int,int,int,int)}
+     * As of JDK 1.1, replaced by {@link #setBounds(int,int,int,int)}.
      */
     void foo3() {}
     // violation below 'Summary javadoc is missing.'

src/test/resources/com/puppycrawl/tools/checkstyle/checks/javadoc/summaryjavadoc/InputSummaryJavadocIncorrect2.java

@@ -16,7 +16,7 @@
 class InputSummaryJavadocIncorrect2 {
 
     /**
-     * As of JDK 1.1, replaced by {@link #setBounds(int,int,int,int)}
+     * As of JDK 1.1, replaced by {@link #setBounds(int,int,int,int)}.
      */
     void foo3() {}
     // violation below 'Summary javadoc is missing.'

src/test/resources/com/puppycrawl/tools/checkstyle/checks/javadoc/summaryjavadoc/InputSummaryJavadocPeriod.java

@@ -37,4 +37,10 @@ void foo7(){}
      * {@summary An especially short bit of Javadoc}
      */ // violation above 'Summary .* missing an ending period.'
     void foo8() {}
+
+    // violation below 'First sentence .* missing an ending period.'
+    /**
+     * Summary sentence containing correct period mid_word, but not at the end
+     */
+    void foo9() throws Exception {}
 }

src/test/resources/com/puppycrawl/tools/checkstyle/checks/javadoc/summaryjavadoc/InputSummaryJavadocPeriodAtEnd.java

@@ -12,7 +12,7 @@
 
 public class InputSummaryJavadocPeriodAtEnd {
     /**
-     * JAXB 1.0 only default validation event handler
+     * JAXB 1.0 only default validation event handler.
      */
     public static final byte NUL = 0;
     // violation below 'Summary javadoc is missing.'
@@ -65,5 +65,18 @@ public void foo5(){
      */
     public void foo6() {
 
+    }
+    // violation below 'First sentence .* missing an ending period.'
+    /**
+     * JAXB 1.0 missing end period
+     */
+    public void foo7() {
+
+    }
+    /**
+     *.period at beginning of line, then summary sentence.
+     */
+    public void foo8() {
+
     }
 }