From 38cbbe86407607a2223027f667075fc574f11cf9 Mon Sep 17 00:00:00 2001
From: callumalpass <callumalpass@gmail.com>
Date: Sat, 3 Oct 2026 13:24:20 +1000
Subject: [PATCH] Fix schema-invalid file metadata selection aliases

---
 apps/writer/src/backend/collection.test.ts | 14 ++++++++++++++
 apps/writer/src/backend/collection.ts      |  5 +++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/apps/writer/src/backend/collection.test.ts b/apps/writer/src/backend/collection.test.ts
index b9f6dae..3027471 100644
--- a/apps/writer/src/backend/collection.test.ts
+++ b/apps/writer/src/backend/collection.test.ts
@@ -1,5 +1,6 @@
 import type { CollectionDescription, JsonObject } from "@mdbase-dev/connect";
 import { describe, expect, it } from "vitest";
+import { validateCanonicalQueryInput } from "../../node_modules/@callumalpass/mdbase/dist/operations/canonical-query.js";
 import { annotationContract, commentContract, manuscriptContract, sourceContract, CollectionSchema, CollectionStore, starterSchema, type CollectionRow } from "./collection.js";
 const impl = (name: string, fields: Record<string, string>) => ({ typeName: name, typeVersion: 1, digest: "test", fields });
 const description: Pick<CollectionDescription, "types" | "contracts" | "configuration"> = {
@@ -61,6 +62,19 @@ describe("collection semantics", () => {
     expect([...narrow.commentScope(["mixed.md"])]).toEqual(["comments/root.md", "comments/reply.md"]);
     expect(narrow.manuscripts[0]?.modified).toBe("2026-01-01");
   });
+  it.each([
+    ["configured collection", new CollectionSchema(description)],
+    ["starter collection", starterSchema()],
+    ["unconfigured collection", new CollectionSchema({ types: [], contracts: [] })],
+  ])("uses schema-valid discovery selection names for a %s", (_name, schema) => {
+    const select = schema.discoverySelect().map(({ name, expression }) => ({ name, expr: expression }));
+    expect(validateCanonicalQueryInput({ select })).toEqual([]);
+  });
+  it("reads manuscript modification time from the named metadata selection", () => {
+    const store = fresh();
+    store.upsert([{ path: "paper.md", types: ["paper"], values: { heading: "Paper", file_mtime: "2026-01-02" } }], true);
+    expect(store.manuscripts).toEqual([{ path: "paper.md", title: "Paper", modified: "2026-01-02" }]);
+  });
   it("escapes literal mapped field names rather than interpreting dots or CEL syntax", () => {
     const schema = new CollectionSchema({ types: [], contracts: [{ ...annotationContract, contractType: "record", digest: "test", schema: {},
       implementations: [impl("highlight", { source: 'a.b["source"]' })] }] });
diff --git a/apps/writer/src/backend/collection.ts b/apps/writer/src/backend/collection.ts
index 5bfedad..ffe9de2 100644
--- a/apps/writer/src/backend/collection.ts
+++ b/apps/writer/src/backend/collection.ts
@@ -120,7 +120,8 @@ export class CollectionSchema {
     }
     return [
       ...[...fields].map((field) => ({ name: field, expression: `record[${JSON.stringify(field)}]` })),
-      ...(modified ? [{ name: "file.mtime", expression: "file.mtime" }] : fields.size ? [] : [{ name: "file.path", expression: "file.path" }]),
+      // Output aliases are field names: dots are valid in expressions, not names.
+      ...(modified ? [{ name: "file_mtime", expression: "file.mtime" }] : fields.size ? [] : [{ name: "file_path", expression: "file.path" }]),
     ];
   }
   annotationFields(types: readonly string[]): Readonly<Record<string, string>> {
@@ -177,7 +178,7 @@ export class CollectionStore {
         }
         case "manuscript": {
           const fields = fieldsOf(effective, binding);
-          const modified = row.values?.["file.mtime"] ?? row.file?.mtime;
+          const modified = row.values?.["file_mtime"] ?? row.file?.mtime;
           const manuscript = retainEffective && previous.manuscript ? previous.manuscript : {
             path: row.path, title: typeof fields["title"] === "string" ? fields["title"] : row.path,
             ...(typeof fields["template"] === "string" ? { template: fields["template"] } : {}),