From 44fb49a96faaf7e276a1583ac71751a4fb06784b Mon Sep 17 00:00:00 2001
From: Christopher Monsanto <chris@monsan.to>
Date: Sat, 15 Aug 2026 22:34:11 -0400
Subject: [PATCH] Refresh stored rule template/display when their computed form
 drifts

They are outside the rule key, so a format change (like the one in the
previous commit) silently disabled rename detection for existing records.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 tools/build/db.ts    | 16 ++++++++++++++++
 tools/build/index.ts | 18 +++++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/tools/build/db.ts b/tools/build/db.ts
index 4a93f95d..1eec899e 100644
--- a/tools/build/db.ts
+++ b/tools/build/db.ts
@@ -211,6 +211,22 @@ export class BuildDb {
         this.db.prepare('DELETE FROM rules WHERE id = ?').run(id);
     }
 
+    // template/display are pure functions of the rule declaration but are not
+    // part of the rule key; refresh stored values that have drifted (e.g. the
+    // template format changed in a newer version of this tool), otherwise
+    // rename detection quietly stops matching older records.
+    refreshRuleMeta(entries : {id : bigint, template : string, display : string | null}[]) : void {
+        if (entries.length === 0) {
+            return;
+        }
+        const update = this.db.prepare('UPDATE rules SET template = ?, display = ? WHERE id = ?');
+        this.db.transaction(() => {
+            for (const e of entries) {
+                update.run(e.template, e.display, e.id);
+            }
+        })();
+    }
+
     close() : void {
         this.db.pragma('wal_checkpoint(TRUNCATE)');
         this.db.close();
diff --git a/tools/build/index.ts b/tools/build/index.ts
index b6ad28bb..3020a2e6 100644
--- a/tools/build/index.ts
+++ b/tools/build/index.ts
@@ -100,14 +100,30 @@ async function main() : Promise<number> {
             }
             return st;
         };
+        const stored = db.loadStoredRules();
         const plan = computePlan({
             current: rules,
-            stored: db.loadStoredRules(),
+            stored,
             hashes,
             statOutput,
             adopt: Boolean(opts.adopt),
         });
 
+        // Keep stored template/display in sync for key-matched rules; they are
+        // outside the key, so e.g. a template format change in this tool would
+        // otherwise silently disable rename detection for old records.
+        if (!dryRun) {
+            const storedByKey = new Map(stored.map(s => [s.key, s]));
+            const staleMeta = [];
+            for (const decl of rules) {
+                const s = storedByKey.get(decl.key);
+                if (s !== undefined && (s.template !== decl.template || s.display !== decl.display)) {
+                    staleMeta.push({id: s.id, template: decl.template, display: decl.display});
+                }
+            }
+            db.refreshRuleMeta(staleMeta);
+        }
+
         const staleOutputs = [];
         const currentOutputs = new Set(rules.flatMap(r => r.outputs));
         for (const s of plan.stale) {