Pass IFDs to libtiff as TIFF_LONG8

[radarhere]

Resolves #8522

#7053 found that "EXIFIFDOffset" tag 34665 was being unexpectedly treated as a TIFF_LONG8 by libtiff. To fix this, it cast many TIFF_LONGs to 64-bits.

This reverts that change. Instead, I found https://gitlab.com/libtiff/libtiff/-/blob/master/libtiff/tif_dirinfo.c#L152-164 explaining that this is special behaviour for the IFD tags.

/*--: EXIFIFD and GPSIFD specified as TIFF_LONG by Aware-Systems and not TIFF_IFD8 as in original LibTiff. However, for IFD-like tags, * libtiff uses the data type TIFF_IFD8 in tiffFields[]-tag definition combined with a special handling procedure in order to write either * a 32-bit value and the TIFF_IFD type-id into ClassicTIFF files or a 64-bit value and the TIFF_IFD8 type-id into BigTIFF files. */ {TIFFTAG_EXIFIFD, 1, 1, TIFF_IFD8, 0, TIFF_SETGET_IFD8, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 1, 0, "EXIFIFDOffset", (TIFFFieldArray *)&exifFieldArray}, {TIFFTAG_ICCPROFILE, -3, -3, TIFF_UNDEFINED, 0, TIFF_SETGET_C32_UINT8, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 1, 1, "ICC Profile", NULL}, {TIFFTAG_GPSIFD, 1, 1, TIFF_IFD8, 0, TIFF_SETGET_IFD8, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 1, 0, "GPSIFDOffset", (TIFFFieldArray *)&gpsFieldArray}, {TIFFTAG_FAXRECVPARAMS, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_CUSTOM, TRUE, FALSE, "FaxRecvParams", NULL}, {TIFFTAG_FAXSUBADDRESS, -1, -1, TIFF_ASCII, 0, TIFF_SETGET_ASCII, TIFF_SETGET_ASCII, FIELD_CUSTOM, TRUE, FALSE, "FaxSubAddress", NULL}, {TIFFTAG_FAXRECVTIME, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_CUSTOM, TRUE, FALSE, "FaxRecvTime", NULL}, {TIFFTAG_FAXDCS, -1, -1, TIFF_ASCII, 0, TIFF_SETGET_ASCII, TIFF_SETGET_ASCII, FIELD_CUSTOM, TRUE, FALSE, "FaxDcs", NULL}, {TIFFTAG_STONITS, 1, 1, TIFF_DOUBLE, 0, TIFF_SETGET_DOUBLE, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 0, 0, "StoNits", NULL}, {TIFFTAG_IMAGESOURCEDATA, -3, -3, TIFF_UNDEFINED, 0, TIFF_SETGET_C32_UINT8, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 1, 1, "Adobe Photoshop Document Data Block", NULL}, {TIFFTAG_INTEROPERABILITYIFD, 1, 1, TIFF_IFD8, 0, TIFF_SETGET_IFD8, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 0, 0, "InteroperabilityIFDOffset", NULL}, 

This PR passes the EXIF, GPSInfo and Interop IFDs to libtiff as TIFF_LONG8.

[mgorny]

Thanks. It fixes the regression, but it doesn't seem to get IFD right still, at least on PowerPC:

____________________________________________________ TestFileLibTiff.test_exif_ifd ____________________________________________________ self = <Tests.test_file_libtiff.TestFileLibTiff object at 0xf60a0c90> def test_exif_ifd(self) -> None: out = io.BytesIO() with Image.open("Tests/images/tiff_adobe_deflate.tif") as im: assert im.tag_v2[34665] == 125456 im.save(out, "TIFF") with Image.open(out) as reloaded: assert 34665 not in reloaded.tag_v2 > im.save(out, "TIFF", tiffinfo={34665: 125456}) Tests/test_file_libtiff.py:709: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ src/PIL/Image.py:2605: in save save_handler(self, fp, filename) src/PIL/TiffImagePlugin.py:1954: in _save encoder = Image._getencoder(im.mode, "libtiff", a, encoderconfig) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ mode = 'RGB', encoder_name = 'libtiff' args = ('RGB', 'tiff_adobe_deflate', 0, '', [(254, 0), (256, 278), (257, 374), (258, 8), (259, 8), (262, 2), ...], {254: 4, 273: 4, 279: 4, 305: 2, ...}) extra = () def _getencoder( mode: str, encoder_name: str, args: Any, extra: tuple[Any, ...] = () ) -> core.ImagingEncoder | ImageFile.PyEncoder: # tweak arguments if args is None: args = () elif not isinstance(args, tuple): args = (args,) try: encoder = ENCODERS[encoder_name] except KeyError: pass else: return encoder(mode, *args + extra) try: # get encoder encoder = getattr(core, f"{encoder_name}_encoder") except AttributeError as e: msg = f"encoder {encoder_name} not available" raise OSError(msg) from e > return encoder(mode, *args + extra) E RuntimeError: Error setting from dictionary src/PIL/Image.py:467: RuntimeError -------------------------------------------------------- Captured stderr call --------------------------------------------------------- _TIFFVSetField: : Bad LONG8 or IFD8 value 538833550496960 for "EXIFIFDOffset" tag 34665 in ClassicTIFF. Tag won't be written to file.

[mgorny]

Hmm:

125456 = 0x1EA10 538833550496960 = 0x1EA10F65ED4C0 

So it's still getting some junk?

[radarhere]

Yes, I jumped the gun slightly.

I've updated the commit. Please try again.

[mgorny]

Thanks! With this change, all tests pass for me now.

[fogti]

perhaps the return value of PyLong_AsLongLong(value) should also be force-casted like (almost) all the others, to make it obvious what type is expected (and make it easier to find wrong modifications of the code in the future).

[radarhere]

I've added a commit to cast to uint64_t

[fogti]

Thanks, looks good.