472386: [CommonMark] Fix pattern for AtxHeader

Task-Url: https://bugs.eclipse.org/472386
Change-Id: I16d404e9fca32dffee05108e3acb37463f657de9
Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>

2 files changed, 11 insertions, 3 deletions

diff --git a/org.eclipse.mylyn.wikitext.commonmark.tests/src/org/eclipse/mylyn/internal/wikitext/commonmark/blocks/AtxHeaderBlockTest.java b/org.eclipse.mylyn.wikitext.commonmark.tests/src/org/eclipse/mylyn/internal/wikitext/commonmark/blocks/AtxHeaderBlockTest.java
index 513c8798f..0f9bd2b83 100644
--- a/org.eclipse.mylyn.wikitext.commonmark.tests/src/org/eclipse/mylyn/internal/wikitext/commonmark/blocks/AtxHeaderBlockTest.java
+++ b/org.eclipse.mylyn.wikitext.commonmark.tests/src/org/eclipse/mylyn/internal/wikitext/commonmark/blocks/AtxHeaderBlockTest.java
@@ -37,6 +37,12 @@ public class AtxHeaderBlockTest {
 		assertTrue(block.canStart(LineSequence.create("###### Y")));
 		assertFalse(block.canStart(LineSequence.create("####### Y")));
 		assertTrue(block.canStart(LineSequence.create("# Y#")));
+		assertFalse(block.canStart(LineSequence.create("#Y")));
+
+		// Bug 472386:
+		assertTrue(block.canStart(LineSequence.create("# #Y")));
+		assertTrue(block.canStart(LineSequence.create("   # Y")));
+		assertFalse(block.canStart(LineSequence.create("\t# Y")));
 	}
 
 	@Test
@@ -44,6 +50,7 @@ public class AtxHeaderBlockTest {
 		assertContent("<h2 id=\"one-two\">One Two</h2>", "## One Two");
 		assertContent("<h2 id=\"one-two\">One Two</h2>", "## One Two #####   ");
 		assertContent("<h2 id=\"one-two\">One Two#</h2>", "## One Two#");
+		assertContent("<h2 id=\"one-two\">#One #Two</h2>", "## #One #Two");
 		assertContent("<p>One</p><h1 id=\"two\">two</h1><p>Three</p>", "One\n# two\nThree");
 		assertContent("<h2></h2>", "##");
 		assertContent("<h2></h2>", "## ##");
@@ -54,4 +61,5 @@ public class AtxHeaderBlockTest {
 		assertContent("<h2 id=\"one-two-three\">One <em>Two</em> \\<strong>three</strong></h2>",
 				"## One *Two* \\\\__three__ ##");
 	}
+
 }
diff --git a/org.eclipse.mylyn.wikitext.commonmark/src/org/eclipse/mylyn/internal/wikitext/commonmark/blocks/AtxHeaderBlock.java b/org.eclipse.mylyn.wikitext.commonmark/src/org/eclipse/mylyn/internal/wikitext/commonmark/blocks/AtxHeaderBlock.java
index 56c3f86df..9cd11bfd5 100644
--- a/org.eclipse.mylyn.wikitext.commonmark/src/org/eclipse/mylyn/internal/wikitext/commonmark/blocks/AtxHeaderBlock.java
+++ b/org.eclipse.mylyn.wikitext.commonmark/src/org/eclipse/mylyn/internal/wikitext/commonmark/blocks/AtxHeaderBlock.java
@@ -28,12 +28,12 @@ import org.eclipse.mylyn.wikitext.core.parser.HeadingAttributes;
 
 public class AtxHeaderBlock extends SourceBlock {
 
-	private final Pattern pattern = Pattern.compile("\\s{0,3}(#{1,6})(?:\\s+([^#\\s].*?))?(\\s+#*)?\\s*");
+	private static final Pattern PATTERN = Pattern.compile(" {0,3}(#{1,6})(?:[ \t]+?(.+?))??(?:[ \t]+#+)?[ \t]*");
 
 	@Override
 	public void process(ProcessingContext context, DocumentBuilder builder, LineSequence lineSequence) {
 		Line currentLine = lineSequence.getCurrentLine();
-		Matcher matcher = pattern.matcher(currentLine.getText());
+		Matcher matcher = PATTERN.matcher(currentLine.getText());
 		checkState(matcher.matches());
 
 		lineSequence.advance();
@@ -72,7 +72,7 @@ public class AtxHeaderBlock extends SourceBlock {
 	@Override
 	public boolean canStart(LineSequence lineSequence) {
 		Line line = lineSequence.getCurrentLine();
-		return line != null && pattern.matcher(line.getText()).matches();
+		return line != null && PATTERN.matcher(line.getText()).matches();
 	}
 
 }