Keep Berry takeover preflight compatible with lock-aware rewrites

Author: mikolalysenko

crates/socket-patch-core/src/patch/redirect/mod.rs

@@ -3233,16 +3233,18 @@ fn berry_cache_key(content: &str) -> Option<String> {
 /// compares the file with its own majority-normalized re-render and fails
 /// (YN0028), while a plain install rewrites every minority line — so it is
 /// refused untouched, `yarn install` normalizes it first.
-/// The per-dep refusal of the yarn berry hosted rewriter that depends only
-/// on the grant, not on the lock: a dep whose grant carries no
-/// `yarnBerry10c0` cache checksum cannot be redirected (berry verifies the
-/// converted cache zip, and only the service can compute that checksum).
+/// The grant prerequisite for creating a new yarn berry hosted pin: a dep
+/// whose grant carries no `yarnBerry10c0` cache checksum cannot be redirected
+/// (berry verifies the converted cache zip, and only the service can compute
+/// that checksum).
 ///
 /// Exposed for the vendored→hosted mode takeover, like
 /// [`preflight_yarn_berry_hosted`]: vendored mode only uses the `tarball`
 /// artifact, so a vendorable patch can lack the berry checksum, and the
 /// takeover must keep such a package vendored instead of reverting it and
 /// then skipping the redirect.
+/// Keep this unconditional gate at the takeover boundary: a lock-aware
+/// rewriter may retain an already complete pin's stored checksum.
 pub fn preflight_yarn_berry_hosted_dep(dep: &DepOverride) -> Result<(), RewriteWarning> {
     if dep.integrity.yarn_berry10c0.is_some() {
         return Ok(());
@@ -3349,16 +3351,19 @@ fn rewrite_yarn_berry(
         let fname = full_name(dep);
         // The API hands the prefixed `10c0/<hex>`; a yarn 4.0.x lock spells
         // its checksums bare, and `--immutable` rejects a respelled one.
-        if let Err(warning) = preflight_yarn_berry_hosted_dep(dep) {
-            result.warnings.push(warning);
-            continue;
-        }
         let Some(checksum) = dep
             .integrity
             .yarn_berry10c0
             .as_deref()
             .map(|c| crate::vendor::yarn_berry_lock::checksum_in_lock_spelling(content, c))
         else {
+            result.warnings.push(RewriteWarning {
+                code: "redirect_yarn_berry_missing_checksum".into(),
+                detail: format!(
+                    "{fname}@{} has no yarnBerry10c0 cache checksum",
+                    dep.version
+                ),
+            });
             continue;
         };
         // Berry versions are UNQUOTED (`  version: 1.3.0`).