From 4c7825d30979cb1bd922f75d1980b0e8773f155c Mon Sep 17 00:00:00 2001
From: Thibaut Decombe <thibaut.decombe@gmail.com>
Date: Sun, 23 Aug 2026 17:19:21 +0200
Subject: [PATCH] Fix raw slice of a nested Jinja block missing its opening tag

A nested block reached from a parent block's children loop had its opening
tag consumed before the start offset was recorded, so `Node::raw` began
after it. Raw content printing ({% raw %} blocks, ignore directives) emits
`raw` verbatim, which dropped the opening tag and made formatting unstable.
---
 markup_fmt/src/parser.rs                      | 24 +++++++++----------
 .../fmt/jinja/control-structure/fixture.jinja |  6 +++++
 .../fmt/jinja/control-structure/fixture.snap  |  6 +++++
 .../tests/fmt/jinja/ignore/nested-block.jinja |  6 +++++
 .../tests/fmt/jinja/ignore/nested-block.snap  |  9 +++++++
 5 files changed, 38 insertions(+), 13 deletions(-)
 create mode 100644 markup_fmt/tests/fmt/jinja/ignore/nested-block.jinja
 create mode 100644 markup_fmt/tests/fmt/jinja/ignore/nested-block.snap

diff --git a/markup_fmt/src/parser.rs b/markup_fmt/src/parser.rs
index ebca70b3..54af5725 100644
--- a/markup_fmt/src/parser.rs
+++ b/markup_fmt/src/parser.rs
@@ -1396,6 +1396,7 @@ impl<'s> Parser<'s> {
                         body.push(JinjaTagOrChildren::Children(children));
                     }
                 }
+                let next_tag_start = self.peek_pos();
                 if let Ok(next_tag) = self.parse_jinja_tag() {
                     let next_tag_name = parse_jinja_tag_name(&next_tag);
                     if next_tag_name
@@ -1409,20 +1410,17 @@ impl<'s> Parser<'s> {
                         && matches!(next_tag_name, "elif" | "elseif" | "else")
                     {
                         body.push(JinjaTagOrChildren::Tag(next_tag));
-                    } else if let Some(JinjaTagOrChildren::Children(nodes)) = body.last_mut() {
-                        nodes.push(
-                            self.with_taken(|parser| {
-                                parser.parse_jinja_tag_or_block(Some(next_tag), children_parser)
-                            })
-                            .map(|(kind, raw)| T::build(kind, raw))?,
-                        );
                     } else {
-                        body.push(JinjaTagOrChildren::Children(vec![
-                            self.with_taken(|parser| {
-                                parser.parse_jinja_tag_or_block(Some(next_tag), children_parser)
-                            })
-                            .map(|(kind, raw)| T::build(kind, raw))?,
-                        ]));
+                        let kind =
+                            self.parse_jinja_tag_or_block(Some(next_tag), children_parser)?;
+                        let node = T::build(kind, unsafe {
+                            self.source.get_unchecked(next_tag_start..self.peek_pos())
+                        });
+                        if let Some(JinjaTagOrChildren::Children(nodes)) = body.last_mut() {
+                            nodes.push(node);
+                        } else {
+                            body.push(JinjaTagOrChildren::Children(vec![node]));
+                        }
                     }
                 } else {
                     break;
diff --git a/markup_fmt/tests/fmt/jinja/control-structure/fixture.jinja b/markup_fmt/tests/fmt/jinja/control-structure/fixture.jinja
index b5cbd7bf..ff61a3f6 100644
--- a/markup_fmt/tests/fmt/jinja/control-structure/fixture.jinja
+++ b/markup_fmt/tests/fmt/jinja/control-structure/fixture.jinja
@@ -90,3 +90,9 @@ There are {{ count }} {{ name }} objects.
         <dt>Realname</dt>
     </dl>
 {% endcall %}
+
+{% if outer %}
+    {% raw %}
+        <p     class="untouched"      >keep</p>
+    {% endraw %}
+{% endif %}
diff --git a/markup_fmt/tests/fmt/jinja/control-structure/fixture.snap b/markup_fmt/tests/fmt/jinja/control-structure/fixture.snap
index cac169f4..a3a38e40 100644
--- a/markup_fmt/tests/fmt/jinja/control-structure/fixture.snap
+++ b/markup_fmt/tests/fmt/jinja/control-structure/fixture.snap
@@ -98,3 +98,9 @@ source: markup_fmt/tests/fmt.rs
     <dt>Realname</dt>
   </dl>
 {% endcall %}
+
+{% if outer %}
+  {% raw %}
+        <p     class="untouched"      >keep</p>
+    {% endraw %}
+{% endif %}
diff --git a/markup_fmt/tests/fmt/jinja/ignore/nested-block.jinja b/markup_fmt/tests/fmt/jinja/ignore/nested-block.jinja
new file mode 100644
index 00000000..c14c33d9
--- /dev/null
+++ b/markup_fmt/tests/fmt/jinja/ignore/nested-block.jinja
@@ -0,0 +1,6 @@
+{% if outer %}
+    <!-- markup-fmt-ignore -->
+    {% if inner %}
+        <p     class="unformatted"      >keep</p>
+    {% endif %}
+{% endif %}
diff --git a/markup_fmt/tests/fmt/jinja/ignore/nested-block.snap b/markup_fmt/tests/fmt/jinja/ignore/nested-block.snap
new file mode 100644
index 00000000..85c26453
--- /dev/null
+++ b/markup_fmt/tests/fmt/jinja/ignore/nested-block.snap
@@ -0,0 +1,9 @@
+---
+source: markup_fmt/tests/fmt.rs
+---
+{% if outer %}
+  <!-- markup-fmt-ignore -->
+  {% if inner %}
+        <p     class="unformatted"      >keep</p>
+    {% endif %}
+{% endif %}