Incomplete markdown patching for codeblocks with >3 backticks (microsoft#203925)

* Fix incomplete markdown handling of links with codespans

* Incomplete markdown patching for codeblocks with >3 backticks

Author: roblourens

src/vs/base/browser/markdownRenderer.ts

@@ -605,7 +605,9 @@ function completeSingleLinePattern(token: marked.Tokens.ListItem | marked.Tokens
 					return completeLinkTargetArg(token);
 				}
 				return completeLinkTarget(token);
-			} else if (lastLine.match(/(^|\s)\[\w/)) {
+			} else if (hasStartOfLinkTarget(lastLine)) {
+				return completeLinkTarget(token);
+			} else if (lastLine.match(/(^|\s)\[\w/) && !token.tokens.slice(i + 1).some(t => hasStartOfLinkTarget(t.raw))) {
 				return completeLinkText(token);
 			}
 		}
@@ -614,6 +616,10 @@ function completeSingleLinePattern(token: marked.Tokens.ListItem | marked.Tokens
 	return undefined;
 }
 
+function hasStartOfLinkTarget(str: string): boolean {
+	return !!str.match(/^[^\[]*\]\([^\)]*$/);
+}
+
 // function completeListItemPattern(token: marked.Tokens.List): marked.Tokens.List | undefined {
 // 	// Patch up this one list item
 // 	const lastItem = token.items[token.items.length - 1];
@@ -639,9 +645,11 @@ export function fillInIncompleteTokens(tokens: marked.TokensList): marked.Tokens
 	let newTokens: marked.Token[] | undefined;
 	for (i = 0; i < tokens.length; i++) {
 		const token = tokens[i];
-		if (token.type === 'paragraph' && token.raw.match(/(\n|^)```/)) {
+		let codeblockStart: RegExpMatchArray | null;
+		if (token.type === 'paragraph' && (codeblockStart = token.raw.match(/(\n|^)(````*)/))) {
+			const codeblockLead = codeblockStart[2];
 			// If the code block was complete, it would be in a type='code'
-			newTokens = completeCodeBlock(tokens.slice(i));
+			newTokens = completeCodeBlock(tokens.slice(i), codeblockLead);
 			break;
 		}
 
@@ -680,9 +688,9 @@ export function fillInIncompleteTokens(tokens: marked.TokensList): marked.Tokens
 	return tokens;
 }
 
-function completeCodeBlock(tokens: marked.Token[]): marked.Token[] {
+function completeCodeBlock(tokens: marked.Token[], leader: string): marked.Token[] {
 	const mergedRawText = mergeRawTokenText(tokens);
-	return marked.lexer(mergedRawText + '\n```');
+	return marked.lexer(mergedRawText + `\n${leader}`);
 }
 
 function completeCodespan(token: marked.Token): marked.Token {

src/vs/base/test/browser/markdownRenderer.test.ts

@@ -513,6 +513,30 @@ suite('MarkdownRenderer', () => {
 				const completeCodeblockTokens = marked.lexer(incompleteCodeblock + '\n```');
 				assert.deepStrictEqual(newTokens, completeCodeblockTokens);
 			});
+
+			test('code block header with more backticks', () => {
+				const incompleteCodeblock = 'some text\n`````js\nconst';
+				const tokens = marked.lexer(incompleteCodeblock);
+				const newTokens = fillInIncompleteTokens(tokens);
+
+				const completeCodeblockTokens = marked.lexer(incompleteCodeblock + '\n`````');
+				assert.deepStrictEqual(newTokens, completeCodeblockTokens);
+			});
+
+			test('code block header containing codeblock', () => {
+				const incompleteCodeblock = `some text
+\`\`\`\`\`js
+const x = 1;
+\`\`\`
+const y = 2;
+\`\`\`
+// foo`;
+				const tokens = marked.lexer(incompleteCodeblock);
+				const newTokens = fillInIncompleteTokens(tokens);
+
+				const completeCodeblockTokens = marked.lexer(incompleteCodeblock + '\n`````');
+				assert.deepStrictEqual(newTokens, completeCodeblockTokens);
+			});
 		});
 
 		function simpleMarkdownTestSuite(name: string, delimiter: string): void {
@@ -687,6 +711,24 @@ suite('MarkdownRenderer', () => {
 				assert.deepStrictEqual(newTokens, completeTokens);
 			});
 
+			test('incomplete link target with extra stuff', () => {
+				const incomplete = '[before `text` after](http://microsoft.com';
+				const tokens = marked.lexer(incomplete);
+				const newTokens = fillInIncompleteTokens(tokens);
+
+				const completeTokens = marked.lexer(incomplete + ')');
+				assert.deepStrictEqual(newTokens, completeTokens);
+			});
+
+			test('incomplete link target with extra stuff and arg', () => {
+				const incomplete = '[before `text` after](http://microsoft.com "more text ';
+				const tokens = marked.lexer(incomplete);
+				const newTokens = fillInIncompleteTokens(tokens);
+
+				const completeTokens = marked.lexer(incomplete + ')');
+				assert.deepStrictEqual(newTokens, completeTokens);
+			});
+
 			test('incomplete link target with arg', () => {
 				const incomplete = 'foo [text](http://microsoft.com "more text here ';
 				const tokens = marked.lexer(incomplete);