[thirdparty/git.git] / Documentation / technical / api-merge.txt

merge API
=========

The merge API helps a program to reconcile two competing sets of
improvements to some files (e.g., unregistered changes from the work
tree versus changes involved in switching to a new branch), reporting
conflicts if found.  The library called through this API is
responsible for a few things.

 * determining which trees to merge (recursive ancestor consolidation);

 * lining up corresponding files in the trees to be merged (rename
   detection, subtree shifting), reporting edge cases like add/add
   and rename/rename conflicts to the user;

 * performing a three-way merge of corresponding files, taking
   path-specific merge drivers (specified in `.gitattributes`)
   into account.

Data structures
---------------

* `mmbuffer_t`, `mmfile_t`

These store data usable for use by the xdiff backend, for writing and
for reading, respectively.  See `xdiff/xdiff.h` for the definitions
and `diff.c` for examples.

* `struct ll_merge_options`

Check merge-ll.h for details.

Low-level (single file) merge
-----------------------------

Check merge-ll.h for details.
Commit	Line	Data
24d113ec JN	1	merge API
	2	=========
	3
	4	The merge API helps a program to reconcile two competing sets of
	5	improvements to some files (e.g., unregistered changes from the work
	6	tree versus changes involved in switching to a new branch), reporting
	7	conflicts if found. The library called through this API is
	8	responsible for a few things.
	9
	10	* determining which trees to merge (recursive ancestor consolidation);
	11
	12	* lining up corresponding files in the trees to be merged (rename
	13	detection, subtree shifting), reporting edge cases like add/add
	14	and rename/rename conflicts to the user;
	15
	16	* performing a three-way merge of corresponding files, taking
	17	path-specific merge drivers (specified in `.gitattributes`)
	18	into account.
	19
712516bc JN	20	Data structures
	21	---------------
	22
	23	* `mmbuffer_t`, `mmfile_t`
	24
	25	These store data usable for use by the xdiff backend, for writing and
	26	for reading, respectively. See `xdiff/xdiff.h` for the definitions
	27	and `diff.c` for examples.
	28
	29	* `struct ll_merge_options`
	30
67238999	31	Check merge-ll.h for details.
712516bc	32
24d113ec JN	33	Low-level (single file) merge
	34	-----------------------------
	35
67238999	36	Check merge-ll.h for details.