From 86d55220960f78a7f057439346ec294c38f6b35c Mon Sep 17 00:00:00 2001
From: "jyc.dev" <jycouet@gmail.com>
Date: Fri, 13 Feb 2026 18:03:47 +0100
Subject: [PATCH] fix: follow-up formatting in `print()` for block-level
 elements (#17699)

Follow-up to #17319.

The `Fragment` visitor in `print()` only flushed sequences on
`RegularElement`, causing block-level elements (`Component`,
`SvelteHead`, `SvelteBoundary`, etc.) to be lumped into the same
sequence as adjacent nodes. This broke tools that programmatically
manipulate the AST (e.g.
[sveltejs/cli#915](https://github.com/sveltejs/cli/pull/915)).

The fix flushes before and after all block-level element types, ensuring
they get their own sequence and proper line separation.

### Before

```svelte
<svelte:head><title>Page Title</title></svelte:head><div>no space</div>
<Component /><Component />
<Component><span>child</span></Component><div>after component</div>
<svelte:boundary><div>boundary content</div></svelte:boundary><div>after boundary</div>
<!--comment--><div>after comment</div>
<div>before comment</div>
<!--comment-->

{#each items as item}
	<div>{item}</div>
{/each}<div>after each</div>

{@render children()}<div>after render</div>
<div>before render</div>
{@render children()}
```

### After

```svelte
<svelte:head><title>Page Title</title></svelte:head>
<div>no space</div>
<Component />
<Component />
<Component><span>child</span></Component>
<div>after component</div>
<svelte:boundary><div>boundary content</div></svelte:boundary>
<div>after boundary</div>
<!--comment-->
<div>after comment</div>
<div>before comment</div>
<!--comment-->

{#each items as item}
	<div>{item}</div>
{/each}

<div>after each</div>
{@render children()}
<div>after render</div>
<div>before render</div>
{@render children()}
```
---
 .changeset/print-block-element-separation.md  |  5 +++
 packages/svelte/src/compiler/print/index.js   | 18 +++++++-
 .../block-element-separation/input.svelte     | 25 +++++++++++
 .../block-element-separation/output.svelte    | 42 +++++++++++++++++++
 4 files changed, 88 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/print-block-element-separation.md
 create mode 100644 packages/svelte/tests/print/samples/block-element-separation/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/block-element-separation/output.svelte

diff --git a/.changeset/print-block-element-separation.md b/.changeset/print-block-element-separation.md
new file mode 100644
index 0000000000..57373fba5b
--- /dev/null
+++ b/.changeset/print-block-element-separation.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: follow-up formatting in `print()` — flush block-level elements into separate sequences
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index 094c578b83..5543b6b581 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -371,9 +371,23 @@ const svelte_visitors = {
 					}
 				}
 			} else {
+				const is_block_element =
+					child_node.type === 'RegularElement' ||
+					child_node.type === 'Component' ||
+					child_node.type === 'SvelteHead' ||
+					child_node.type === 'SvelteFragment' ||
+					child_node.type === 'SvelteBoundary' ||
+					child_node.type === 'SvelteDocument' ||
+					child_node.type === 'SvelteSelf' ||
+					child_node.type === 'SvelteWindow' ||
+					child_node.type === 'SvelteComponent' ||
+					child_node.type === 'SvelteElement' ||
+					child_node.type === 'SlotElement' ||
+					child_node.type === 'TitleElement';
+
+				if (is_block_element && sequence.length > 0) flush();
 				sequence.push(child_node);
-
-				if (child_node.type === 'RegularElement') flush();
+				if (is_block_element) flush();
 			}
 		}
 
diff --git a/packages/svelte/tests/print/samples/block-element-separation/input.svelte b/packages/svelte/tests/print/samples/block-element-separation/input.svelte
new file mode 100644
index 0000000000..2a721648fe
--- /dev/null
+++ b/packages/svelte/tests/print/samples/block-element-separation/input.svelte
@@ -0,0 +1,25 @@
+<svelte:head><title>Page Title</title></svelte:head><div>no space</div>
+<Component /><Component />
+<Component><span>child</span></Component><div>after component</div>
+<svelte:boundary><div>boundary content</div></svelte:boundary><div>after boundary</div>
+<!--comment--><div>after comment</div>
+<div>before comment</div><!--comment-->
+{#each items as item}<div>{item}</div>{/each}<div>after each</div>
+{@render children()}<div>after render</div>
+<div>before render</div>{@render children()}
+
+<Component />   <div>with spaces</div>
+<Component><span>child</span></Component>   <div>spaces after component</div>
+<!--comment-->   <div>spaces after comment</div>
+{@render children()}   <div>spaces after render</div>
+
+<Component />
+<div>newline between</div>
+<!--comment-->
+<div>newline after comment</div>
+{#each items as item}
+<div>{item}</div>
+{/each}
+<div>newline after each</div>
+{@render children()}
+<div>after render</div>
diff --git a/packages/svelte/tests/print/samples/block-element-separation/output.svelte b/packages/svelte/tests/print/samples/block-element-separation/output.svelte
new file mode 100644
index 0000000000..380e4f7cee
--- /dev/null
+++ b/packages/svelte/tests/print/samples/block-element-separation/output.svelte
@@ -0,0 +1,42 @@
+<svelte:head><title>Page Title</title></svelte:head>
+<div>no space</div>
+<Component />
+<Component />
+<Component><span>child</span></Component>
+<div>after component</div>
+<svelte:boundary><div>boundary content</div></svelte:boundary>
+<div>after boundary</div>
+<!--comment-->
+<div>after comment</div>
+<div>before comment</div>
+<!--comment-->
+
+{#each items as item}
+	<div>{item}</div>
+{/each}
+
+<div>after each</div>
+{@render children()}
+<div>after render</div>
+<div>before render</div>
+{@render children()}
+<Component />
+<div>with spaces</div>
+<Component><span>child</span></Component>
+<div>spaces after component</div>
+<!--comment-->
+<div>spaces after comment</div>
+{@render children()}
+<div>spaces after render</div>
+<Component />
+<div>newline between</div>
+<!--comment-->
+<div>newline after comment</div>
+
+{#each items as item}
+	<div>{item}</div>
+{/each}
+
+<div>newline after each</div>
+{@render children()}
+<div>after render</div>