ignore invalid trailing pure annotations (#4068)

that were incorrectly associated with subsequent calls Co-authored-by: Lukas Taegert-Atkinson <lukastaegert@users.noreply.github.com>
rollup · May 14, 2021 · c40d206 · c40d206
1 parent 3345267
commit c40d206
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Showing 6 changed files with 113 additions and 6 deletions.
diff --git a/src/Graph.ts b/src/Graph.ts
@@ -136,7 +136,7 @@ export default class Graph {
 
 		options.onComment = onCommentOrig;
 
-		markPureCallExpressions(comments, ast);
+		markPureCallExpressions(comments, ast, code);
 
 		return ast;
 	}

diff --git a/src/utils/pureComments.ts b/src/utils/pureComments.ts
@@ -19,18 +19,34 @@ basicWalker.PropertyDefinition = function (node: any, st: any, c: any) {
 };
 
 interface CommentState {
+	code: string;
 	commentIndex: number;
 	commentNodes: acorn.Comment[];
 }
 
+function isOnlyWhitespaceOrComments(code: string) {
+	// streamline the typical case
+	if (/^\s*$/.test(code)) return true;
+	try {
+		// successful only if it's a valid Program without statements
+		const ast = acorn.parse(code, { ecmaVersion: 'latest' }) as any;
+		return ast.body && ast.body.length === 0;
+	} catch {
+		// should never be reached -
+		// the entire module was previously successfully parsed
+	}
+	return false;
+}
+
 function handlePureAnnotationsOfNode(
 	node: acorn.Node,
 	state: CommentState,
 	type: string = node.type
 ) {
 	let commentNode = state.commentNodes[state.commentIndex];
 	while (commentNode && node.start >= commentNode.end) {
-		markPureNode(node, commentNode);
+		const between = state.code.substring(commentNode.end, node.start);
+		if (isOnlyWhitespaceOrComments(between)) markPureNode(node, commentNode);
 		commentNode = state.commentNodes[++state.commentIndex];
 	}
 	if (commentNode && commentNode.end <= node.end) {
@@ -62,8 +78,9 @@ function markPureNode(
 const pureCommentRegex = /[@#]__PURE__/;
 const isPureComment = (comment: acorn.Comment) => pureCommentRegex.test(comment.value);
 
-export function markPureCallExpressions(comments: acorn.Comment[], esTreeAst: acorn.Node) {
+export function markPureCallExpressions(comments: acorn.Comment[], esTreeAst: acorn.Node, code: string) {
 	handlePureAnnotationsOfNode(esTreeAst, {
+		code,
 		commentIndex: 0,
 		commentNodes: comments.filter(isPureComment)
 	});

diff --git a/test/form/samples/pure-comment-line-break/_expected.js b/test/form/samples/pure-comment-line-break/_expected.js
@@ -6,7 +6,7 @@ console.log('should remain impure');
 console.log('code');
 console.log('should remain impure');
 
-console.log('code');
+console.log('code')/*@__PURE__*/;
 console.log('should remain impure');
 console.log('should remain impure');
 
@@ -16,7 +16,7 @@ console.log('should remain impure');
 console.log('code'),
 console.log('should remain impure');
 
-console.log('code'),
+console.log('code')/*@__PURE__*/,
 console.log('should remain impure');
 
 console.log('should remain impure');
@@ -35,3 +35,21 @@ console.log('should remain impure', x);
 {
 	console.log('should remain impure');
 }
+keep1() /*@__PURE__*/ ; keep2();
+keep3() ; 
+keep4() /*@__PURE__*/ ; /* other comment */ keep5();
+keep6() /*@__PURE__*/ ; // other comment
+keep7();
+keep8() /*@__PURE__*/ && keep9();
+
+/*@__PURE__*/ Drop1(), // FIXME: unrelated issue
+Keep1() /*@__PURE__*/ , Keep2(),
+Keep3() , 
+Keep4() /*@__PURE__*/ , /* other comment */ Keep5(),
+Keep6() /*@__PURE__*/ , // other comment
+Keep7(),
+Keep8() /*@__PURE__*/ && Keep9();
+
+// FIXME: unrelated issue
+/*@__PURE__*/ Drop10(),
+/*@__PURE__*/ Drop13();
diff --git a/test/form/samples/pure-comment-line-break/main.js b/test/form/samples/pure-comment-line-break/main.js
@@ -42,3 +42,31 @@ console.log('should remain impure', code);
 if (true) {
 	console.log('should remain impure');
 }
+
+/*@__PURE__*/ drop1();
+/*@__PURE__*/
+drop2();
+keep1() /*@__PURE__*/ ; keep2();
+keep3() ; /*@__PURE__*/
+drop3();
+keep4() /*@__PURE__*/ ; /* other comment */ keep5();
+keep6() /*@__PURE__*/ ; // other comment
+keep7();
+keep8() /*@__PURE__*/ && keep9();
+
+/*@__PURE__*/ Drop1(), // FIXME: unrelated issue
+/*@__PURE__*/
+Drop2(),
+Keep1() /*@__PURE__*/ , Keep2(),
+Keep3() , /*@__PURE__*/
+Drop3(),
+Keep4() /*@__PURE__*/ , /* other comment */ Keep5(),
+Keep6() /*@__PURE__*/ , // other comment
+Keep7(),
+Keep8() /*@__PURE__*/ && Keep9();
+
+// FIXME: unrelated issue
+/*@__PURE__*/ Drop10(),
+/*@__PURE__*/ Drop11(),
+/*@__PURE__*/ Drop12(),
+/*@__PURE__*/ Drop13();
diff --git a/test/form/samples/pure-comments-disabled/_expected.js b/test/form/samples/pure-comments-disabled/_expected.js
@@ -2,5 +2,27 @@
 /*@__PURE__*/ a();
 /*@__PURE__*/ new a();
 
-console.log('code');
+console.log('code')/*@__PURE__*/;
 console.log('should remain impure');
+
+/*@__PURE__*/ drop1();
+/*@__PURE__*/
+drop2();
+keep1() /*@__PURE__*/ ; keep2();
+keep3() ; /*@__PURE__*/
+drop3();
+keep4() /*@__PURE__*/ ; /* other comment */ keep5();
+keep6() /*@__PURE__*/ ; // other comment
+keep7();
+keep8() /*@__PURE__*/ && keep9();
+
+/*@__PURE__*/ Drop1(),
+/*@__PURE__*/
+Drop2(),
+Keep1() /*@__PURE__*/ , Keep2(),
+Keep3() , /*@__PURE__*/
+Drop3(),
+Keep4() /*@__PURE__*/ , /* other comment */ Keep5(),
+Keep6() /*@__PURE__*/ , // other comment
+Keep7(),
+Keep8() /*@__PURE__*/ && Keep9();
diff --git a/test/form/samples/pure-comments-disabled/main.js b/test/form/samples/pure-comments-disabled/main.js
@@ -5,3 +5,25 @@
 console.log('code')/*@__PURE__*/;
 /*@__PURE__*/(() => {})();
 console.log('should remain impure');
+
+/*@__PURE__*/ drop1();
+/*@__PURE__*/
+drop2();
+keep1() /*@__PURE__*/ ; keep2();
+keep3() ; /*@__PURE__*/
+drop3();
+keep4() /*@__PURE__*/ ; /* other comment */ keep5();
+keep6() /*@__PURE__*/ ; // other comment
+keep7();
+keep8() /*@__PURE__*/ && keep9();
+
+/*@__PURE__*/ Drop1(),
+/*@__PURE__*/
+Drop2(),
+Keep1() /*@__PURE__*/ , Keep2(),
+Keep3() , /*@__PURE__*/
+Drop3(),
+Keep4() /*@__PURE__*/ , /* other comment */ Keep5(),
+Keep6() /*@__PURE__*/ , // other comment
+Keep7(),
+Keep8() /*@__PURE__*/ && Keep9();