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Bug 4375 - Possible ABI break between 2.0.8 and 2.0.9
Summary: Possible ABI break between 2.0.8 and 2.0.9
Status: RESOLVED INVALID
Alias: None
Product: SDL
Classification: Unclassified
Component: *don't know* (show other bugs)
Version: 2.0.9
Hardware: x86_64 Linux
: P2 normal
Assignee: Ryan C. Gordon
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-11-09 23:34 UTC by Javier Jardón
Modified: 2018-11-12 21:56 UTC (History)
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Description Javier Jardón 2018-11-09 23:34:49 UTC 
Hi,

trying to upgrade sdl2 from 2.0.8 to 2.0.9 in our project, we have discovered a possible ABI break.

Here what our tool has reported [1]:

```
┌─────────────────────────────────────────┐
│ ABI Break: libSDL2-2.0.so.0:libSDL2-2.0 │
└─────────────────────────────────────────┘

Functions changes summary: 0 Removed, 1 Changed (10 filtered out), 0 Added (29 filtered out) functions
Variables changes summary: 0 Removed, 0 Changed, 0 Added (5 filtered out) variables

1 function with some indirect sub-type change:

  [C]'function void SDL_AddEventWatch(SDL_EventFilter, void*)' at SDL_dynapi_procs.h:159:1 has some indirect sub-type changes:
    parameter 1 of type 'typedef SDL_EventFilter' has sub-type changes:
      underlying type 'int (void*, SDL_Event*)*' changed:
        in pointed to type 'function type int (void*, SDL_Event*)':
          parameter 2 of type 'SDL_Event*' has sub-type changes:
            in pointed to type 'typedef SDL_Event' at SDL_events.h:595:1:
              underlying type 'union SDL_Event' at SDL_events.h:525:1 changed:
                type size hasn't changed
                2 data member insertions:
                  'SDL_DisplayEvent SDL_Event::display' at SDL_events.h:561:1
                  'SDL_SensorEvent SDL_Event::sensor' at SDL_events.h:578:1

```

We suspect is a false positive, but we wanted to confirm with you first

[1] https://gitlab.com/freedesktop-sdk/freedesktop-sdk/merge_requests/652#note_113869091
Comment 1 Ryan C. Gordon 2018-11-10 00:51:38 UTC 
My reading of that report is that we added new fields to a union (we did), but that the union’s size didn’t change (should be correct)...so I conclude this is a false positive.

Please reopen if I read this incorrectly!

--ryan.
Comment 2 Sam Lantinga 2018-11-12 21:56:35 UTC 
Yup, that's correct.