Repository: pulldown-cmark/pulldown-cmark (rust)

Issue:
Blocks inside alert body is parsed as blocks outside the body
## Repro

Save this content as `foo.md`

```markdown
> [!Note]
> - Foo
```

Then run the following command in this repository

```sh
cargo run -- -G < foo.md
```

## Expected behavior

The list is parsed as the content inside the alert body:

```html
<blockquote class="markdown-alert-note">
<ul>
<li>Foo</li>
</ul>
</blockquote>
```

## Actual behavior

The list is parsed as the content outside the alert body:

```html
<blockquote class="markdown-alert-note">
</blockquote>
<ul>
<li>Foo</li>
</ul>
```

## Environment

- Rust: 1.79
- pulldown-cmark: 36d576ece45928fd2cc5532394110de5c86f2528

## Additional info

GitHub renders `- Foo` as a content inside the alert block as follows:

> [!Note]
> - Foo

I'll make a pull request to fix this issue.

Pull request description:
Fix parsing blocks inside alert body
Fixes #907

The root cause is that the parser eats `> ` at the next line after eating the `> [!Note]` line. So the content is parsed as if it is outside the body:

```markdown
> [!Note]
> - Foo
```

is parsed as

```markdown
> [!Note]
- Foo
```

The `> ` at the next line should not be eaten to know the block quote continues.

Patch:
diff --git a/pulldown-cmark/specs/blockquotes_tags.txt b/pulldown-cmark/specs/blockquotes_tags.txt
index 98d1610..cb338b4 100644
--- a/pulldown-cmark/specs/blockquotes_tags.txt
+++ b/pulldown-cmark/specs/blockquotes_tags.txt
@@ -191,3 +191,14 @@ Like lazy continuations, the blockquote marker is still needed to make nested bl
 <ul><li>sink ships</li></ul></blockquote>
 </li></ul>
 ````````````````````````````````
+
+When an unknown tag is found, parser backtracks and the block is parsed as a normal blockquote:
+```````````````````````````````` example
+> [!Hello]
+> This should be a normal block quote.
+.
+<blockquote>
+<p>[!Hello]
+This should be a normal block quote.</p>
+</blockquote>
+````````````````````````````````
diff --git a/pulldown-cmark/specs/regression.txt b/pulldown-cmark/specs/regression.txt
index 27c89a3..ee98115 100644
--- a/pulldown-cmark/specs/regression.txt
+++ b/pulldown-cmark/specs/regression.txt
@@ -2570,3 +2570,16 @@ _**
 ^_</li>
 </ul>
 ````````````````````````````````
+
+ISSUE #907
+
+```````````````````````````````` example
+> [!Note]
+> - Foo
+.
+<blockquote class="markdown-alert-note">
+<ul>
+<li>Foo</li>
+</ul>
+</blockquote>
+````````````````````````````````
diff --git a/pulldown-cmark/src/scanners.rs b/pulldown-cmark/src/scanners.rs
index 15cdd27..274e345 100644
--- a/pulldown-cmark/src/scanners.rs
+++ b/pulldown-cmark/src/scanners.rs
@@ -243,9 +243,6 @@ impl<'a> LineStart<'a> {
             if tag.is_some() && self.scan_ch(b']') {
                 if let Some(nl) = scan_blank_line(&self.bytes[self.ix..]) {
                     self.ix += nl;
-                    while self.scan_ch(b'>') {
-                        self.scan_space(1);
-                    }
                     tag
                 } else {
                     None


Test patch:
diff --git a/pulldown-cmark/tests/suite/blockquotes_tags.rs b/pulldown-cmark/tests/suite/blockquotes_tags.rs
index 77a1932..9827039 100644
--- a/pulldown-cmark/tests/suite/blockquotes_tags.rs
+++ b/pulldown-cmark/tests/suite/blockquotes_tags.rs
@@ -239,3 +239,17 @@ fn blockquotes_tags_test_17() {
 
     test_markdown_html(original, expected, false, false, false);
 }
+
+#[test]
+fn blockquotes_tags_test_18() {
+    let original = r##"> [!Hello]
+> This should be a normal block quote.
+"##;
+    let expected = r##"<blockquote>
+<p>[!Hello]
+This should be a normal block quote.</p>
+</blockquote>
+"##;
+
+    test_markdown_html(original, expected, false, false, false);
+}
diff --git a/pulldown-cmark/tests/suite/regression.rs b/pulldown-cmark/tests/suite/regression.rs
index 3d665b6..d6783c8 100644
--- a/pulldown-cmark/tests/suite/regression.rs
+++ b/pulldown-cmark/tests/suite/regression.rs
@@ -3071,3 +3071,18 @@ _**
 
     test_markdown_html(original, expected, false, false, false);
 }
+
+#[test]
+fn regression_test_195() {
+    let original = r##"> [!Note]
+> - Foo
+"##;
+    let expected = r##"<blockquote class="markdown-alert-note">
+<ul>
+<li>Foo</li>
+</ul>
+</blockquote>
+"##;
+
+    test_markdown_html(original, expected, false, false, false);
+}