Hi, Le 12/07/2025 à 12:42, Sebastian Ramacher a écrit :
Control: tags -1 moreinfo On 2025-07-12 10:35:40 +0200, Arnaud Ferraris wrote: The bug reads as if libtiff broke its ABI. A rebuild of libdng is hence the wrong solution. Can you shed some light on the cause of the crash that was reported as #1106598? Cheers
I admit I don't understand every aspect of this issue, but I'll try to give as much details as possible: TIFFSetField uses a variable number of arguments, the expected number being dependent on the tag definition.
If a tag definition change affects the expected number of arguments, this might not warrant an ABI version bump (depending on how strictly you interpret ABI version requirements), but does has the effect of breaking binary compatibility for users of this tag.
The definition for the CFAPATTERN tag changed in 4.5.0, causing initial issues (worked around by an #if #else block in the upstream libdng code), and the change was somehow reverted between 4.5.1 and 4.7.0, requiring to revert back to the code used before libtiff 4.5.0.
Bottom line is: strictly speaking, yes, libtiff broke its ABI. However it seems to have gone unnoticed except for libdng, so I'm not sure whether it's libdng misusing libtiff in some weird way, or libtiff getting the blame entirely. Rebuilding libdng fixes the issue anyway, so it's a kind of "good enough" solution.
Cheers, Arnaud
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