handle unclosed blocks

packages/svelte/src/compiler/phases/1-parse/index.js

@@ -164,14 +164,15 @@ export class Parser {
 	/**
 	 * @param {string} str
 	 * @param {boolean} required
+	 * @param {boolean} required_in_loose
 	 */
-	eat(str, required = false) {
+	eat(str, required = false, required_in_loose = true) {
 		if (this.match(str)) {
 			this.index += str.length;
 			return true;
 		}
 
-		if (required) {
+		if (required && (!this.loose || required_in_loose)) {
 			e.expected_token(this.index, str);
 		}
 

packages/svelte/src/compiler/phases/1-parse/state/tag.js

@@ -454,43 +454,66 @@ function close(parser) {
 	const start = parser.index - 1;
 
 	let block = parser.current();
+	/** Only relevant/reached for loose parsing mode */
+	let matched;
 
 	switch (block.type) {
 		case 'IfBlock':
-			parser.eat('if', true);
+			matched = parser.eat('if', true, false);
+
+			if (!matched) {
+				block.end = start - 1;
+				parser.pop();
+				close(parser);
+				return;
+			}
+
 			parser.allow_whitespace();
 			parser.eat('}', true);
+
 			while (block.elseif) {
 				block.end = parser.index;
 				parser.stack.pop();
 				block = /** @type {AST.IfBlock} */ (parser.current());
 			}
+
 			block.end = parser.index;
 			parser.pop();
 			return;
 
 		case 'EachBlock':
-			parser.eat('each', true);
+			matched = parser.eat('each', true, false);
 			break;
 		case 'KeyBlock':
-			parser.eat('key', true);
+			matched = parser.eat('key', true, false);
 			break;
 		case 'AwaitBlock':
-			parser.eat('await', true);
+			matched = parser.eat('await', true, false);
 			break;
 		case 'SnippetBlock':
-			parser.eat('snippet', true);
+			matched = parser.eat('snippet', true, false);
 			break;
 
 		case 'RegularElement':
-			// TODO handle implicitly closed elements
+			if (parser.loose) {
-			e.block_unexpected_close(start);
+				matched = false;
+			} else {
+				// TODO handle implicitly closed elements
+				e.block_unexpected_close(start);
+			}
 			break;
 
 		default:
 			e.block_unexpected_close(start);
 	}
 
+	if (!matched) {
+		block.end = start - 1;
+		parser.pop();
+		close(parser);
+		return;
+	}
+
 	parser.allow_whitespace();
 	parser.eat('}', true);
 	block.end = parser.index;

packages/svelte/tests/parser-legacy/samples/loose-unclosed-block/input.svelte

@@ -0,0 +1,20 @@
+<div>
+	{#if foo}
+</div>
+
+<Comp>
+	{#key bar}
+</Comp>
+
+<div>
+	{#if foo}
+		{#if bar}
+	{/if}
+</div>
+
+{#if foo}
+	{#key bar}
+{/if}
+
+{#each x as y}
+<p>hi</p>

packages/svelte/tests/parser-legacy/samples/loose-unclosed-block/output.json

@@ -0,0 +1,276 @@
+{
+	"html": {
+		"type": "Fragment",
+		"start": 0,
+		"end": 150,
+		"children": [
+			{
+				"type": "Element",
+				"start": 0,
+				"end": 23,
+				"name": "div",
+				"attributes": [],
+				"children": [
+					{
+						"type": "Text",
+						"start": 5,
+						"end": 7,
+						"raw": "\n\t",
+						"data": "\n\t"
+					},
+					{
+						"type": "IfBlock",
+						"start": 7,
+						"end": 17,
+						"expression": {
+							"type": "Identifier",
+							"start": 12,
+							"end": 15,
+							"loc": {
+								"start": {
+									"line": 2,
+									"column": 6
+								},
+								"end": {
+									"line": 2,
+									"column": 9
+								}
+							},
+							"name": "foo"
+						},
+						"children": []
+					}
+				]
+			},
+			{
+				"type": "Text",
+				"start": 23,
+				"end": 25,
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"type": "InlineComponent",
+				"start": 25,
+				"end": 51,
+				"name": "Comp",
+				"attributes": [],
+				"children": [
+					{
+						"type": "Text",
+						"start": 31,
+						"end": 33,
+						"raw": "\n\t",
+						"data": "\n\t"
+					},
+					{
+						"type": "KeyBlock",
+						"start": 33,
+						"end": 44,
+						"expression": {
+							"type": "Identifier",
+							"start": 39,
+							"end": 42,
+							"loc": {
+								"start": {
+									"line": 6,
+									"column": 7
+								},
+								"end": {
+									"line": 6,
+									"column": 10
+								}
+							},
+							"name": "bar"
+						},
+						"children": []
+					}
+				]
+			},
+			{
+				"type": "Text",
+				"start": 51,
+				"end": 53,
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"type": "Element",
+				"start": 53,
+				"end": 95,
+				"name": "div",
+				"attributes": [],
+				"children": [
+					{
+						"type": "Text",
+						"start": 58,
+						"end": 60,
+						"raw": "\n\t",
+						"data": "\n\t"
+					},
+					{
+						"type": "IfBlock",
+						"start": 60,
+						"end": 89,
+						"expression": {
+							"type": "Identifier",
+							"start": 65,
+							"end": 68,
+							"loc": {
+								"start": {
+									"line": 10,
+									"column": 6
+								},
+								"end": {
+									"line": 10,
+									"column": 9
+								}
+							},
+							"name": "foo"
+						},
+						"children": [
+							{
+								"type": "IfBlock",
+								"start": 72,
+								"end": 88,
+								"expression": {
+									"type": "Identifier",
+									"start": 77,
+									"end": 80,
+									"loc": {
+										"start": {
+											"line": 11,
+											"column": 7
+										},
+										"end": {
+											"line": 11,
+											"column": 10
+										}
+									},
+									"name": "bar"
+								},
+								"children": []
+							}
+						]
+					}
+				]
+			},
+			{
+				"type": "Text",
+				"start": 95,
+				"end": 97,
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"type": "IfBlock",
+				"start": 97,
+				"end": 124,
+				"expression": {
+					"type": "Identifier",
+					"start": 102,
+					"end": 105,
+					"loc": {
+						"start": {
+							"line": 15,
+							"column": 5
+						},
+						"end": {
+							"line": 15,
+							"column": 8
+						}
+					},
+					"name": "foo"
+				},
+				"children": [
+					{
+						"type": "KeyBlock",
+						"start": 108,
+						"end": 119,
+						"expression": {
+							"type": "Identifier",
+							"start": 114,
+							"end": 117,
+							"loc": {
+								"start": {
+									"line": 16,
+									"column": 7
+								},
+								"end": {
+									"line": 16,
+									"column": 10
+								}
+							},
+							"name": "bar"
+						},
+						"children": []
+					}
+				]
+			},
+			{
+				"type": "Text",
+				"start": 124,
+				"end": 126,
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"type": "EachBlock",
+				"start": 126,
+				"end": 150,
+				"children": [
+					{
+						"type": "Element",
+						"start": 141,
+						"end": 150,
+						"name": "p",
+						"attributes": [],
+						"children": [
+							{
+								"type": "Text",
+								"start": 144,
+								"end": 146,
+								"raw": "hi",
+								"data": "hi"
+							}
+						]
+					}
+				],
+				"context": {
+					"type": "Identifier",
+					"name": "y",
+					"start": 138,
+					"loc": {
+						"start": {
+							"line": 19,
+							"column": 12,
+							"character": 138
+						},
+						"end": {
+							"line": 19,
+							"column": 13,
+							"character": 139
+						}
+					},
+					"end": 139
+				},
+				"expression": {
+					"type": "Identifier",
+					"start": 133,
+					"end": 134,
+					"loc": {
+						"start": {
+							"line": 19,
+							"column": 7
+						},
+						"end": {
+							"line": 19,
+							"column": 8
+						}
+					},
+					"name": "x"
+				}
+			}
+		]
+	}
+}

packages/svelte/tests/parser-legacy/samples/loose-unclosed-tag/input.svelte

@@ -6,5 +6,9 @@
 	<span>
 </div>
 
+{#if foo}
+	<div>
+{/if}
+
 <div>
 <p>hi</p>

packages/svelte/tests/parser-legacy/samples/loose-unclosed-tag/output.json

@@ -2,7 +2,7 @@
 	"html": {
 		"type": "Fragment",
 		"start": 0,
-		"end": 59,
+		"end": 83,
 		"children": [
 			{
 				"type": "Element",
@@ -83,30 +83,76 @@
 				"data": "\n\n"
 			},
 			{
-				"type": "Element",
+				"type": "IfBlock",
 				"start": 44,
-				"end": 59,
+				"end": 66,
+				"expression": {
+					"type": "Identifier",
+					"start": 49,
+					"end": 52,
+					"loc": {
+						"start": {
+							"line": 9,
+							"column": 5
+						},
+						"end": {
+							"line": 9,
+							"column": 8
+						}
+					},
+					"name": "foo"
+				},
+				"children": [
+					{
+						"type": "Element",
+						"start": 55,
+						"end": 61,
+						"name": "div",
+						"attributes": [],
+						"children": [
+							{
+								"type": "Text",
+								"start": 60,
+								"end": 61,
+								"raw": "\n",
+								"data": "\n"
+							}
+						]
+					}
+				]
+			},
+			{
+				"type": "Text",
+				"start": 66,
+				"end": 68,
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"type": "Element",
+				"start": 68,
+				"end": 83,
 				"name": "div",
 				"attributes": [],
 				"children": [
 					{
 						"type": "Text",
-						"start": 49,
+						"start": 73,
-						"end": 50,
+						"end": 74,
 						"raw": "\n",
 						"data": "\n"
 					},
 					{
 						"type": "Element",
-						"start": 50,
+						"start": 74,
-						"end": 59,
+						"end": 83,
 						"name": "p",
 						"attributes": [],
 						"children": [
 							{
 								"type": "Text",
-								"start": 53,
+								"start": 77,
-								"end": 55,
+								"end": 79,
 								"raw": "hi",
 								"data": "hi"
 							}