On Fri, Sep 01, 2017 at 03:07:16AM +0000, Daniel Shahaf wrote: > Evgeny Kotkov wrote on Thu, 31 Aug 2017 19:05 +0300: > > Daniel Shahaf <d...@daniel.shahaf.name> writes: > > > Is adding this function an ABI-compatible change? The docstring of > > > svn_delta_editor_t does say """ > > > > > > * @note Don't try to allocate one of these yourself. Instead, always > > > * use svn_delta_default_editor() or some other constructor, to ensure > > > * that unused slots are filled in with no-op functions. > > > > > > """, but an API consumer might have interpreted this note as meaning "You > > > may > > > use malloc(..., sizeof(svn_delta_editor_t)) if you take care to initialize > > > all struct members", in which case, his code will not be ABI compatible > > > with 1.10. > > > > I think that adding this callback does not affect the ABI compatibility. > > The note says "Don't try to allocate one of these yourself", whereas the > > malloc(..., sizeof(svn_delta_editor_t)) example does exactly the opposite. > > I'm not sure I'm getting through here. > > The note does say "Don't allocate one of these yourself" but in the > second sentence implies that the reason for this is that if you allocate > it yourself and don't initialize all pointer-to-function members, > Trouble will ensue. Therefore, the note could be construed as meaning > that it is okay to allocate one of these yourself if you take care to > initialize all pointer members.
The fact that a user can choose not to use the recommended API doesn't mean that there is an ABI break. A user can already choose to allocate the structure themselves and not initialize everything. Adding an item to the struct doesn't change that. I ran abi-compliance-checker[0] against the head of branches/1.9.x and trunk. It shows no incompatibility issues. The report is attached for anyone that wants to view it. [0]: http://ispras.linuxbase.org/index.php/ABI_compliance_checker Cheers, -- James GPG Key: 4096R/91BF BF4D 6956 BD5D F7B7 2D23 DFE6 91AE 331B A3DB
abi-check.tar.gz
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