From 1ede66e5c0e9fec4a7dcd61dd0a03bf48f6a8ae5 Mon Sep 17 00:00:00 2001
From: sneak <sneak@sneak.berlin>
Date: Thu, 1 Oct 2026 21:11:05 +0000
Subject: [PATCH] Photo implements one method per PhotoExif field

Photo now implements a mapped type with one method per PhotoExif field,
each taking exif()'s options and giving that field's type, so the
build's type check fails when PhotoExif has a field Photo has no method
for, whatever the test fixtures hold. The test comment and TODO.md say
so.

Model: opus-5-5
---
 TODO.md                              | 6 ++++--
 src/library/read.ts                  | 9 ++++++++-
 test/library/content-library.test.ts | 4 ++++
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/TODO.md b/TODO.md
index 6550ebd..3d1af8a 100644
--- a/TODO.md
+++ b/TODO.md
@@ -30,8 +30,10 @@ declares one.
   `dateTimeOriginal()`, `offsetTimeOriginal()`, `exposureTime()`, `fNumber()`,
   `iso()`, `focalLength()`, `orientation()`, `gpsLatitude()`, `gpsLongitude()`
   and `gpsAltitude()` (issue 148). Each calls `exif()` and returns its one
-  field, or undefined when the file lacks it. A test checks, on the JPEG and the
-  HEIC, that every field `exif()` returns has a method giving the same value.
+  field, or undefined when the file lacks it. `Photo` implements a type with one
+  method per `PhotoExif` field, so the build's type check fails when a field has
+  no method. A test checks, on the JPEG and the HEIC, that each method gives the
+  same value as `exif()`.
 
 - 2026-10-01: Each original's save path is
   `YYYY/YYYY-MM/YYYY-MM-DD/YYYY-MM-DD.<fileID>.<ext>` under the library's
diff --git a/src/library/read.ts b/src/library/read.ts
index 9ea594e..3aac9ce 100644
--- a/src/library/read.ts
+++ b/src/library/read.ts
@@ -42,11 +42,18 @@ const byNewest = (a: PhotoRecord, b: PhotoRecord): number =>
 const byNewestAlbum = (a: AlbumRecord, b: AlbumRecord): number =>
     b.updationTime - a.updationTime || b.collectionID - a.collectionID;
 
+// A method for each `PhotoExif` field, named after it, taking the options
+// `exif()` takes and giving that field. `Photo` implements it, so the build's
+// type check fails when `PhotoExif` has a field `Photo` has no method for.
+type PhotoExifMethods = {
+    [K in keyof PhotoExif]-?: (opts?: ContentOptions) => Promise<PhotoExif[K]>;
+};
+
 // A single photo. Field access mirrors `PhotoRecord`; `record()` returns the
 // underlying plain record for callers that need the IPC-safe value. `file` is
 // the membership the record is read from, so the save path carries the date of
 // `takenAt` and stays known after a refresh removes the file from the library.
-export class Photo {
+export class Photo implements PhotoExifMethods {
     constructor(
         private readonly rec: PhotoRecord,
         private readonly file: EnteFile,
diff --git a/test/library/content-library.test.ts b/test/library/content-library.test.ts
index cce917b..ffa0cc7 100644
--- a/test/library/content-library.test.ts
+++ b/test/library/content-library.test.ts
@@ -686,6 +686,10 @@ describe("Photo save path, local copy, content and EXIF", () => {
         await lib.close();
     });
 
+    // The build's type check, not this test, makes sure `Photo` has a method
+    // for every `PhotoExif` field, whatever the fixtures hold: `Photo`
+    // implements a type with one method per field. This test checks that each
+    // method gives the same value as exif().
     it.each([
         ["JPEG", JPEG_WITH_EXIF],
         ["HEIC", HEIC_WITH_EXIF],