Merge PR #1924: Do not read a sibling's shared stem sidecar on import (#1905)

docs/parity-checklist.md: header keeps the newer 2026-10-18 change

docs/parity-checklist.md

@@ -170,7 +170,7 @@ differences and missing bindings are in [ui-parity.md](ui-parity.md#shortcuts).
 | LR-META-COPYRIGHT-DEFAULT | Default copyright on import | P1 | ✅ | `cmd:library.preferences` (`import.copyright`, `import.creator`), `crates/ui-egui/src/panels/settings.rs` | Settings → Import → Metadata; fills only photos without their own |
 | LR-META-LOCATION | Location editing | P2 | 🟡 | `cmd:photo.setMeta` (`location`, `city`, `state`, `country`, `gps`), `cmd:metadata.reverseGeocode` | place fields and GPS (decimal or degrees / minutes / seconds) edited in Info, read/written as IPTC Core / Photoshop / EXIF XMP; Show on Map opens OpenStreetMap; Fill Location fills empty City / State / Country from GPS offline (GeoNames, downloaded on request: `cmd:metadata.downloadPlaceNames`); no embedded map |
 | LR-META-COPYPASTE | Copy / paste metadata | P2 | ✅ | `cmd:photo.copyMetadata`, `cmd:photo.pasteMetadata` | title, caption, alt text, extended description, copyright (notice, status, usage terms, info URL), creator, place fields, keywords; `fields` picks a subset |
-| LR-META-XMP | XMP read/write | P0 | ✅ | `cmd:photo.saveMetadataToFile`, `cmd:photo.readMetadataFromFile`, `cmd:library.xmpPreferences`, `crates/engine/src/sidecar.rs`, `docs/xmp-interop.md` | sidecar wins for metadata; a sidecar capture time (`exif:DateTimeOriginal` / `photoshop:DateCreated` / `xmp:CreateDate`) fills in only when the file has none; saving merges into an existing sidecar (`crates/meta/src/xmp_merge.rs`): another app's `crs:`, `xmpMM:History` and unknown namespaces are kept byte for byte, an unreadable sidecar is backed up first; with stem naming, files sharing a stem (raw + JPEG) get separate sidecars (`<file>.xmp` for all but the raw); a `crs:` custom white balance on a relative-WB raw is shifted from `crs:AsShotTemperature` rather than read as Kelvin, or kept As Shot and reported when the packet has no as-shot white (issue #510); heal and clone spots (`crs:RetouchAreas`, legacy `crs:RetouchInfo`) are read into our spots (`crates/engine/src/crs_masks.rs`, see `docs/xmp-interop.md` → Spot removal); radial masks (`Mask/CircularGradient`) keep Lightroom's inside / outside: `crs:Flipped="true"` is the effect-inside flag of current masks and of the legacy Radial Filter, `crs:MaskInverted` the inversion, checked against Lightroom Classic's renders (issue #1815); Read Metadata from File never writes the sidecar back, even with auto-write on, so another app's later `crs:` edits are still read (issue #934) |
+| LR-META-XMP | XMP read/write | P0 | ✅ | `cmd:photo.saveMetadataToFile`, `cmd:photo.readMetadataFromFile`, `cmd:library.xmpPreferences`, `crates/engine/src/sidecar.rs`, `docs/xmp-interop.md` | sidecar wins for metadata; a sidecar capture time (`exif:DateTimeOriginal` / `photoshop:DateCreated` / `xmp:CreateDate`) fills in only when the file has none; saving merges into an existing sidecar (`crates/meta/src/xmp_merge.rs`): another app's `crs:`, `xmpMM:History` and unknown namespaces are kept byte for byte, an unreadable sidecar is backed up first; with stem naming, files sharing a stem (raw + JPEG) get separate sidecars (`<file>.xmp` for all but the raw; an import ranks the files it is adding the same way, so a TIFF or JPEG arriving beside its raw reads its own `<file>.xmp` and never the raw's `IMG_0001.xmp`, issue #1905); a `crs:` custom white balance on a relative-WB raw is shifted from `crs:AsShotTemperature` rather than read as Kelvin, or kept As Shot and reported when the packet has no as-shot white (issue #510); heal and clone spots (`crs:RetouchAreas`, legacy `crs:RetouchInfo`) are read into our spots (`crates/engine/src/crs_masks.rs`, see `docs/xmp-interop.md` → Spot removal); radial masks (`Mask/CircularGradient`) keep Lightroom's inside / outside: `crs:Flipped="true"` is the effect-inside flag of current masks and of the legacy Radial Filter, `crs:MaskInverted` the inversion, checked against Lightroom Classic's renders (issue #1815); Read Metadata from File never writes the sidecar back, even with auto-write on, so another app's later `crs:` edits are still read (issue #934) |
 | LR-META-EXIF-FULL | Full EXIF/IPTC [Classic] | P1 | ✅ | `cmd:photo.allMetadata`, `cmd:dialog.allMetadata`, `crates/meta/src/tags.rs`, `crates/meta/src/exif.rs`, `crates/meta/src/iptc.rs` | read and written on export; Info ▸ All Metadata…: every TIFF / EXIF / GPS / interop tag (named, common values spelled out) and the XMP fields, searchable; metadata presets |
 
 ## F. Edit panel — global adjustments (EDIT)
@@ -892,3 +892,4 @@ Latin stays upright. Advanced Japanese composition remains open. Regression cove
 | 2026-10-13 | minor | LRC-LIB-CATALOG-IMPORT review: offline Local promotion and result dismissal across library switches covered; redundant operation/settings copies removed. Status and summary counts unchanged. |
 | 2026-10-14 | patch | LRC-LIB-CATALOG-IMPORT: reconciled with upstream phased progress, cancellation kinds, WAL-only import, translations and current progress tracking. Status and summary counts unchanged. |
 | 2026-10-13 | minor | KEYC-COMPARE: `=` / `-` (also `+`) increase / decrease the grid thumbnail size (`view.thumbSizeUp` / `view.thumbSizeDown`, View menu), grids only; status unchanged (🟡) |
+| 2026-10-16 | patch | LR-META-XMP: a TIFF or JPEG imported beside a raw of its stem reads its own `<file>.xmp` and takes nothing from the raw's `IMG_0001.xmp`, whether it arrives with the raw or after it (a stem sidecar belongs to one file: a raw first, then the first by name); status unchanged (✅) |

docs/xmp-interop.md

@@ -10,7 +10,7 @@ other tools), and let LightCraft pick up edits made elsewhere.
 |---|---|
 | Name | `<stem>.xmp` by default (`IMG_0001.CR3` → `IMG_0001.xmp`); `<file>.xmp` (`IMG_0001.CR3.xmp`) with `naming: "full"`. Reading accepts either (preferred first) and `.XMP`. With stem naming, files sharing a stem don't share a sidecar: see *Shared names* below. |
 | Write | `photo.saveMetadataToFile {ids?}` (Photo ▸ Save Metadata to File, ⌘S), or automatically after every change with `library.xmpPreferences {autoWrite: true}` (File ▸ Automatically Write Changes into XMP). Slider drags are written once, when the drag ends; undo/redo rewrite the sidecar. An existing sidecar is **merged into, never replaced** (see *Saving into an existing sidecar*). Written atomically (temp file, fsync, rename). The result lists `written`, `merged` and `backups`. |
-| Read | On import (`library.import`, the report counts `sidecars`), and `photo.readMetadataFromFile {ids?}` (one undo step). For raw/DNG files without a sidecar, the XMP embedded in the file is used. `photo.readMetadataFromFile` never writes the sidecar, even with auto-write on: writing back what it has just read would add `lc:settings`, which later reads prefer over another app's `crs:` edits (issue #934). |
+| Read | On import (`library.import`, the report counts `sidecars`), and `photo.readMetadataFromFile {ids?}` (one undo step). For raw/DNG files without a sidecar, the XMP embedded in the file is used. `photo.readMetadataFromFile` never writes the sidecar, even with auto-write on: writing back what it has just read would add `lc:settings`, which later reads prefer over another app's `crs:` edits (issue #934). A file arriving in an import is ranked as if it were catalogued already: it reads its own `<file>.xmp` when another file of its stem (a raw first) owns the shared stem sidecar (issue #1905). |
 | Preferences | `library.xmpPreferences {autoWrite?, naming?: stem\|full}`, stored in the library's `prefs.json`. |
 
 What we write (standard namespaces, so other tools can read the metadata):
@@ -74,6 +74,10 @@ library share a stem, the stem sidecar belongs to one of them — a raw first, o
 the others write and read `<file>.xmp` (`IMG_0001.JPG.xmp`), falling back to the stem sidecar for reading when they
 have none. So saving one photo never overwrites the other's metadata (`Session::sidecar_naming`).
 
+An import ranks the files it is adding the same way, before they are catalogued: a TIFF or JPEG arriving beside a
+raw of its stem reads its own `<file>.xmp` and takes nothing from the raw's `IMG_0001.xmp`, whether it arrives
+with the raw or after it (issue #1905).
+
 ## Face regions (MWG)
 
 LightCraft reads face, pet, focus and barcode regions in the Metadata Working Group's region schema