fix(test): skip typechecking for blocks inside HTML comments (#13889)

cli/tests/integration/test_tests.rs

@@ -103,6 +103,12 @@ itest!(markdown_full_block_names {
   output: "test/markdown_full_block_names.out",
 });
 
+itest!(markdown_ignore_html_comment {
+  args: "test --doc --allow-all test/markdown_with_comment.md",
+  exit_code: 1,
+  output: "test/markdown_with_comment.out",
+});
+
 itest!(text {
   args: "test --doc --allow-all test/text.md",
   exit_code: 0,

cli/tests/testdata/test/markdown_with_comment.md

@@ -0,0 +1,36 @@
+# Documentation
+
+The following examples are inside HTML comments and will not trigger the
+type-checker:
+
+<!-- ```ts ignore
+const value: Invalid = "ignored";
+``` -->
+
+<!--
+```ts
+const a: string = 42;
+```
+-->
+
+<!--
+
+This is a comment.
+
+```ts
+const a: string = 42;
+```
+
+Something something more comments.
+
+```typescript
+const a: boolean = "true";
+```
+
+-->
+
+The following example will trigger the type-checker to fail:
+
+```ts
+const a: string = 42;
+```

cli/tests/testdata/test/markdown_with_comment.out

@@ -0,0 +1,5 @@
+Check [WILDCARD]/test/markdown_with_comment.md$34-37.ts
+error: TS2322 [ERROR]: Type 'number' is not assignable to type 'string'.
+const a: string = 42;
+      ^
+    at [WILDCARD]/test/markdown_with_comment.md$34-37.ts:1:7

cli/tools/test.rs

@@ -543,6 +543,10 @@ fn extract_files_from_regex_blocks(
   let files = blocks_regex
     .captures_iter(source)
     .filter_map(|block| {
+      if block.get(1) == None {
+        return None;
+      }
+
       let maybe_attributes: Option<Vec<_>> = block
         .get(1)
         .map(|attributes| attributes.as_str().split(' ').collect());
@@ -663,7 +667,12 @@ fn extract_files_from_fenced_blocks(
   source: &str,
   media_type: MediaType,
 ) -> Result<Vec<File>, AnyError> {
-  let blocks_regex = Regex::new(r"```([^\r\n]*)\r?\n([\S\s]*?)```")?;
+  // The pattern matches code blocks as well as anything in HTML comment syntax,
+  // but it stores the latter without any capturing groups. This way, a simple
+  // check can be done to see if a block is inside a comment (and skip typechecking)
+  // or not by checking for the presence of capturing groups in the matches.
+  let blocks_regex =
+    Regex::new(r"(?s)<!--.*?-->|```([^\r\n]*)\r?\n([\S\s]*?)```")?;
   let lines_regex = Regex::new(r"(?:\# ?)?(.*)")?;
 
   extract_files_from_regex_blocks(