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Revision 6aba117d5cf7128e7bc942888263552fe927e13f authored by Elijah Newren on 29 August 2018, 07:06:13 UTC, committed by Junio C Hamano on 30 August 2018, 14:58:59 UTC 
am: avoid directory rename detection when calling recursive merge machinery
 
Let's say you have the following three trees, where Base is from one commit
behind either master or branch:

   Base  : bar_v1, foo/{file1, file2, file3}
   branch: bar_v2, foo/{file1, file2},       goo/file3
   master: bar_v3, foo/{file1, file2, file3}

Using git-am (or am-based rebase) to apply the changes from branch onto
master results in the following tree:

   Result: bar_merged, goo/{file1, file2, file3}

This is not what users want; they did not rename foo/ -> goo/, they only
renamed one file within that directory.  The reason this happens is am
constructs fake trees (via build_fake_ancestor()) of the following form:

   Base_bfa  : bar_v1, foo/file3
   branch_bfa: bar_v2, goo/file3

Combining these two trees with master's tree:

   master: bar_v3, foo/{file1, file2, file3},

You can see that merge_recursive_generic() would see branch_bfa as renaming
foo/ -> goo/, and master as just adding both foo/file1 and foo/file2.  As
such, it ends up with goo/{file1, file2, file3}

The core problem is that am does not have access to the original trees; it
can only construct trees using the blobs involved in the patch.  As such,
it is not safe to perform directory rename detection within am -3.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 5fdddd9
Raw File
refspec.h 
#ifndef REFSPEC_H
#define REFSPEC_H

#define TAG_REFSPEC "refs/tags/*:refs/tags/*"
extern const struct refspec_item *tag_refspec;

struct refspec_item {
	unsigned force : 1;
	unsigned pattern : 1;
	unsigned matching : 1;
	unsigned exact_sha1 : 1;

	char *src;
	char *dst;
};

#define REFSPEC_FETCH 1
#define REFSPEC_PUSH 0

#define REFSPEC_INIT_FETCH { .fetch = REFSPEC_FETCH }
#define REFSPEC_INIT_PUSH { .fetch = REFSPEC_PUSH }

struct refspec {
	struct refspec_item *items;
	int alloc;
	int nr;

	const char **raw;
	int raw_alloc;
	int raw_nr;

	int fetch;
};

void refspec_item_init(struct refspec_item *item, const char *refspec, int fetch);
void refspec_item_clear(struct refspec_item *item);
void refspec_init(struct refspec *rs, int fetch);
void refspec_append(struct refspec *rs, const char *refspec);
void refspec_appendn(struct refspec *rs, const char **refspecs, int nr);
void refspec_clear(struct refspec *rs);

int valid_fetch_refspec(const char *refspec);

struct argv_array;
/*
 * Determine what <prefix> values to pass to the peer in ref-prefix lines
 * (see Documentation/technical/protocol-v2.txt).
 */
void refspec_ref_prefixes(const struct refspec *rs,
			  struct argv_array *ref_prefixes);

#endif /* REFSPEC_H */
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