71 lines
2.4 KiB
Plaintext
71 lines
2.4 KiB
Plaintext
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merge API
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=========
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The merge API helps a program to reconcile two competing sets of
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improvements to some files (e.g., unregistered changes from the work
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tree versus changes involved in switching to a new branch), reporting
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conflicts if found. The library called through this API is
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responsible for a few things.
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* determining which trees to merge (recursive ancestor consolidation);
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* lining up corresponding files in the trees to be merged (rename
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detection, subtree shifting), reporting edge cases like add/add
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and rename/rename conflicts to the user;
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* performing a three-way merge of corresponding files, taking
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path-specific merge drivers (specified in `.gitattributes`)
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into account.
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Low-level (single file) merge
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-----------------------------
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`ll_merge`::
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Perform a three-way single-file merge in core. This is
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a thin wrapper around `xdl_merge` that takes the path and
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any merge backend specified in `.gitattributes` or
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`.git/info/attributes` into account. Returns 0 for a
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clean merge.
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The caller:
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1. allocates an mmbuffer_t variable for the result;
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2. allocates and fills variables with the file's original content
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and two modified versions (using `read_mmfile`, for example);
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3. calls ll_merge();
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4. reads the output from result_buf.ptr and result_buf.size;
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5. releases buffers when finished (free(ancestor.ptr); free(ours.ptr);
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free(theirs.ptr); free(result_buf.ptr);).
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If the modifications do not merge cleanly, `ll_merge` will return a
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nonzero value and `result_buf` will generally include a description of
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the conflict bracketed by markers such as the traditional `<<<<<<<`
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and `>>>>>>>`.
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The `ancestor_label`, `our_label`, and `their_label` parameters are
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used to label the different sides of a conflict if the merge driver
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supports this.
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The `flag` parameter is a bitfield:
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- The least significant bit indicates whether this is an internal
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merge to consolidate ancestors for a recursive merge.
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- The next two bits allow local conflicts to be automatically
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resolved in favor of one side or the other (as in 'git merge-file'
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`--ours`/`--theirs`/`--union` for 01, 10, and 11, respectively).
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Everything else
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---------------
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Talk about <merge-recursive.h> and merge_file():
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- merge_trees() to merge with rename detection
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- merge_recursive() for ancestor consolidation
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- try_merge_command() for other strategies
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- conflict format
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- merge options
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(Daniel, Miklos, Stephan, JC)
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