fix(apple): HDRImageType printed invented values; guard test reachability

[swackhamer]

Stacked on #404 (base retargets to main when #404 merges). Completes the revival of all 21 unreachable test files.

The production bug the dead tests were hiding

DECODE_HDR_TYPE (Apple.pm 0x000a HDRImageType) carried nine invented values:

0 Off | 1 HDR | 2 HDR (Original) | 3 Auto HDR | 4 Smart HDR | 5..8 Smart HDR 2 .. Smart HDR 5

ExifTool 13.59 Apple.pm declares exactly two:

0x000a => {
    Name => 'HDRImageType',
    PrintConv => { 3 => 'HDR Image', 4 => 'Original Image' },
},

So on a real iPhone file oxidex printed "Auto HDR" where ExifTool prints "HDR Image", and "Smart HDR" where ExifTool prints "Original Image" — under the real tag name Apple:HDRImageType. Per AGENTS.md, a plausible-but-wrong value under a real tag name is worse than an absent tag: it does not crash, and nothing downstream can tell.

The undeclared test asserted 0 => "Off" and 4 => "Smart HDR" — so simply declaring it would have passed and pinned the wrong values. That is the whole thesis of this work in one tag.

Table trimmed to ExifTool's two entries; unmapped values fall through to "Unknown (N)", matching ExifTool. Three in-repo assertions that encoded the old values are corrected, and a new test pins 0 => "Unknown (0)" so the invented labels cannot come back.

apple_makernotes_tests.rs: 18 → 9

Deleted 10 tests asserting names with 0 hits in ExifTool 13.59: FacingCamera, LensModel, NightMode, PortraitMode, SceneDetection. Two more asserted SemanticStyle as a SHORT enum at 0x2E — wrong twice over: ExifTool puts SemanticStyle at 0x0040 and decodes it with ConvertPLIST (a property list, not an enum), and 0x002e is CameraType.

Rewrote the HDR tests to ExifTool's values, added the unmapped-value guard, and rebuilt test_apple_multiple_tags on two verified tags (0x000a HDRImageType, 0x0005 AETarget).

samsung_makernotes_tests.rs: 23 → 6

Deleted 17 tests asserting names with 0 hits: SceneOptimizer, SceneType, SingleTake, ExpertRAW, NightMode, GalaxyLensType, ZoomLevel, PortraitEffect, DirectorsView, ProMode, SuperSteady, FoodMode, ObjectTracking, MultiFrameNoiseReduction (Sony.pm only).

Two near-misses are recorded in the file because they look like hits:

• %Image::ExifTool::Samsung::PortraitEffect is a real table name, but it is JSON-processed with string keys and yields PortraitEffectID, PortraitEffectLevel, … — there is no Samsung:PortraitEffect tag, and it is not a numeric MakerNote IFD entry.
• SceneType exists in FlashPix.pm / Exif.pm / DICOM.pm, not Samsung.pm.

Kept 4 passing: parser_trait, MakerNoteVersion (0x0001), DeviceType (0x0002 → 0x2000 'High-end NX Camera'), and SamsungModelID retargeted from 0x100123a => "NX1" (absent from ExifTool — its only NX1 is commented out at 0x5001038) to 0x100101c => 'NX10', the one mapping where oxidex's MODEL_ID_DECODER and ExifTool agree.

Two ColorSpace tests are #[ignore]d, not deleted. The PrintConv is right, but SAMSUNG_COLOR_SPACE is 0x0221 and 0x0221 appears nowhere in Samsung.pm — ExifTool puts ColorSpace at 0xa011 in Samsung::Type2. Consequence on a real file: ColorSpace is never emitted, and whatever really lives at 0x0221 would be misread as ColorSpace. The tests encode ExifTool's id so they fail until the constant is fixed. Bending them to 0x0221 would pin the defect; deleting them would lose it.

The guard

tests/test_file_reachability.rs re-derives the reachable set from the tests/*.rs roots by following mod / #[path] edges transitively, and fails listing any orphan. It independently reproduced the original 21-file set while this work was in progress. tests/ffi/build.rs is exempt — it is a Cargo build script, not a test module.

Also found, reported separately (not fixed here)

Five more Apple decoders disagree with ExifTool. Worst is ImageCaptureType (0x0014), where every shared key is wrong — value 10, very common on modern iPhones, prints "Screenshot" instead of ExifTool's "Photo". OISMode, GreenGhostMitigationStatus and SignalToNoiseRatioType invent labels for tags where ExifTool has no PrintConv at all and prints a raw integer.

Verification

• 3354 lib + 567 integration + 17 unit + 1 reachability tests pass under --all-features.
• cargo clippy --all-features -- -D warnings clean; cargo fmt --all -- --check clean.
• Ground truth: ExifTool 13.59, searched with /usr/bin/grep -a (the shell grep is ugrep with --ignore-files and gives false negatives).

🤖 Generated with Claude Code