Don't try to keep all on oneline for Jinja

markup_fmt/src/printer.rs

@@ -412,8 +412,15 @@ impl<'s> DocGen<'s> for Element<'s> {
         docs.push(Doc::text(formatted_tag_name.clone()));
 
         match self.attrs.as_slice() {
-            [single_attr] if !is_whitespace_sensitive => {
-                // Try to avoid breaking on multiple lines for a single attribute.
+            [single_attr]
+                if !is_whitespace_sensitive
+                    && !matches!(
+                        single_attr,
+                        Attribute::JinjaTagOrBlock(..) | Attribute::VentoTagOrBlock(..)
+                    ) =>
+            {
+                // Avoid breaking on multiple lines for a single attribute in non whitespace sensitive context.
+                // Skip this for templating Blocks because they usually span across multiple lines.
                 docs.push(Doc::space());
                 docs.push(single_attr.doc(ctx, &state));
 

markup_fmt/tests/fmt/jinja/attributes/single-attr.snap

@@ -1,27 +1,35 @@
 ---
 source: markup_fmt/tests/fmt.rs
 ---
-<tr {% if targeted_fooo and not foo_bar_bar_bar == mykey %}
-  class="collapse"{% endif %}>
+<tr
+  {% if targeted_fooo and not foo_bar_bar_bar == mykey %}
+    class="collapse"{% endif %}
+>
 </tr>
 
-<div {% if not line.fields|length_is:'1' %}
-  class="field-box{% if field.field.name %}
-    field-{{ field.field.name }}{% endif %}{%
-    if not field.is_readonly and field.errors
-  %}
-    errors{% endif %}{% if field.field.is_hidden %}
-    hidden{% endif %}"{% elif field.is_checkbox %}
-  class="checkbox-row"
-{% endif %}>
+<div
+  {% if not line.fields|length_is:'1' %}
+    class="field-box{% if field.field.name %}
+      field-{{ field.field.name }}{% endif %}{%
+      if not field.is_readonly and field.errors
+    %}
+      errors{% endif %}{% if field.field.is_hidden %}
+      hidden{% endif %}"{% elif field.is_checkbox %}
+    class="checkbox-row"
+  {% endif %}
+>
 </div>
 
-<picture {% for key, val in attributes.items %}
-  {{ key }}="{{ val }}"
-{% endfor %}>
+<picture
+  {% for key, val in attributes.items %}
+    {{ key }}="{{ val }}"
+  {% endfor %}
+>
 </picture>
 
-<div {% if field.field.causes_red_card %}data-red-card{%
-  elif field.field.causes_yellow_card
-%}data-yellow-card{% endif %}>
+<div
+  {% if field.field.causes_red_card %}data-red-card{%
+    elif field.field.causes_yellow_card
+  %}data-yellow-card{% endif %}
+>
 </div>