From eb475356664e2cd3ec3eb8be6dbc227f1b227205 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 13 Oct 2026 19:16:18 +0000
Subject: [PATCH] fix(ssr): strip the shell-end marker from client-mode shells

@solidjs/web 2.0.0-rc.15 (solidjs/solid#4002) ends every shell that
rendered <HydrationScript /> with an unguarded `_$HY.s[id]=1` script.
Client mode already strips the HydrationScript bootstrap from a Document
shared with SSR mode, so the marker was left behind and threw
`_$HY is not defined`. Strip it with the bootstrap.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01R2FCNsvaipU3xXx9p83VUs
---
 .changeset/client-mode-shell-end-marker.md |  5 +++++
 src/ssr/index.ts                           | 14 +++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/client-mode-shell-end-marker.md

diff --git a/.changeset/client-mode-shell-end-marker.md b/.changeset/client-mode-shell-end-marker.md
new file mode 100644
index 0000000..6795040
--- /dev/null
+++ b/.changeset/client-mode-shell-end-marker.md
@@ -0,0 +1,5 @@
+---
+'@solidjs/vite-plugin': patch
+---
+
+Client start mode now strips the shell-end marker script along with the `<HydrationScript />` bootstrap. `@solidjs/web` 2.0.0-rc.15 (solidjs/solid#4002) closes every shell that rendered `<HydrationScript />` with `<script>_$HY.s[id]=1,…</script>`, and a Document shared with SSR mode carries `<HydrationScript />`. Once the plugin stripped the bootstrap, that marker threw `_$HY is not defined` in client-mode shells, in dev and in the prerendered `index.html`. Shells from earlier `@solidjs/web` versions have no marker and are unchanged.
diff --git a/src/ssr/index.ts b/src/ssr/index.ts
index d4491c3..6c8a026 100644
--- a/src/ssr/index.ts
+++ b/src/ssr/index.ts
@@ -1397,8 +1397,20 @@ export function startServe(
       );
     }
     lines.push(`      chunk = chunk.replace('</head>', ${headParts.join(' + ')} + '</head>');`);
+    lines.push(`    }`);
+    if (clientMode) {
+      // The shell-end marker (@solidjs/web 2.0.0-rc.15, solidjs/solid#4002)
+      // closes every shell that rendered `<HydrationScript />`. It writes to
+      // `_$HY` without a guard, so it goes with the bootstrap stripped above;
+      // left alone it throws `_$HY is not defined`. It follows the shell's
+      // records rather than its head, so it is matched in any chunk.
+      lines.push(
+        `    if (chunk.includes('_$HY.s[')) {`,
+        `      chunk = chunk.replace(/<script(?:\\s[^>]*)?>_\\$HY\\.s\\[[\\s\\S]*?<\\/script>/, '');`,
+        `    }`,
+      );
+    }
     lines.push(
-      `    }`,
       `    if (first) { first = false; chunk = '<!DOCTYPE html>' + chunk; }`,
       `    return chunk;`,
       `  };`,