delta/git.git, branch jc/rerere-multi

rerere: remove an null statement

2016-05-19T19:51:22+00:00

J6t spotted that previous commit added an empty statement by
mistake.

Signed-off-by: Junio C Hamano

rerere: plug memory leaks upon "rerere forget" failure

2016-05-11T23:25:32+00:00

Signed-off-by: Junio C Hamano

rerere: adjust 'forget' to multi-variant world order

2016-04-06T22:54:41+00:00

Because conflicts with the same contents inside conflict blocks
enclosed by "<<<<<<<" and ">>>>>>>" can now have multiple variants
to help three-way merge to adjust to the differences outside the
conflict blocks, "rerere forget $path" needs to be taught that there
may be multiple recorded resolutions that share the same conflict
hash (which groups the conflicts with "the same contents inside
conflict blocks"), among which there are some that would not be
relevant to the conflict we are looking at.  These "other variants"
that happen to share the same conflict hash should not be cleared,
and the variant that would apply to the current conflict may not be
the zero-th one (which is the only one that is cleared by the
current code).

After finding the conflict hash, iterate over the existing variants
and try to resolve the conflict using each of them to find the one
that "cleanly" resolves the current conflict.  That is the one we
want to forget and record the preimage for, so that the user can
record the corrected resolution.

Signed-off-by: Junio C Hamano

rerere: split code to call ll_merge() further

2016-04-06T22:52:40+00:00

The merge() helper function is given an existing rerere ID (i.e. the
name of the .git/rr-cache/* subdirectory, and the variant number)
that identifies one  pair, try to see if the
conflicted state in the given path can be resolved by using the pair,
and if this succeeds, then update the conflicted path with the
result in the working tree.

To implement rerere_forget() in the multiple variant world, we'd
need a helper to do the "see if a  pair cleanly
resolves a conflicted state we have in-core" part, without actually
touching any file in the working tree, in order to identify which
variant(s) to remove.  Split the logic to do so into a separate
helper function try_merge() out of merge().

Signed-off-by: Junio C Hamano

rerere: move code related to "forget" together

2016-04-06T22:52:40+00:00

"rerere forget" is the only user of handle_cache() helper, which in
turn is the only user of rerere_io that reads from an in-core buffer
whose getline method is implemented as rerere_mem_getline().  Gather
them together.

Signed-off-by: Junio C Hamano

rerere: gc and clear

2016-04-06T22:52:22+00:00

Adjust "git rerere gc" and "git rerere clear" to the new world order
with rerere database with multiple variants for the same shape of
conflicts.

Signed-off-by: Junio C Hamano

rerere: do use multiple variants

2016-03-15T22:32:40+00:00

This enables the multiple-variant support for real.  Multiple
conflicts of the same shape can have differences in contexts where
they appear, interfering the replaying of recorded resolution of one
conflict to another, and in such a case, their resolutions are
recorded as different variants under the same conflict ID.

We still need to adjust garbage collection codepaths for this
change, but the basic "replay" functionality is functional with
this change.

Signed-off-by: Junio C Hamano

t4200: rerere a merge with two identical conflicts

2016-03-15T22:32:19+00:00

When the context of multiple identical conflicts are different, two
seemingly the same conflict resolution cannot be safely applied.

In such a case, at least we should be able to record these two
resolutions separately in the rerere database, and reuse them when
we see the same conflict later.

Signed-off-by: Junio C Hamano

rerere: allow multiple variants to exist

2016-03-15T22:30:58+00:00

The shape of the conflict in a path determines the conflict ID.  The
preimage and postimage pair that was recorded for the conflict ID
previously may or may not replay well for the conflict we just saw.

Currently, we punt when the previous resolution does not cleanly
replay, but ideally we should then be able to record the currently
conflicted path by assigning a new 'variant', and then record the
resolution the user is going to make.

Introduce a mechanism to have more than one variant for a given
conflict ID; we do not actually assign any variant other than 0th
variant yet at this step.

Signed-off-by: Junio C Hamano

rerere: delay the recording of preimage

2016-03-15T22:29:54+00:00

We record the preimage only when there is no directory to record the
conflict we encountered, i.e. when $GIT_DIR/rr-cache/$ID does not
exist.  As the plan is to allow multiple  pairs
as variants for the same conflict ID eventually, this logic needs to
go.

As the first step in that direction, stop the "did we create the
directory?  Then we record the preimage" logic.  Instead, we record
if a preimage does not exist when we saw a conflict in a path.  Also
make sure that we remove a stale postimage, which most likely is
totally unrelated to the resolution of this new conflict, when we
create a new preimage under $ID when $GIT_DIR/rr-cache/$ID already
exists.

In later patches, we will further update this logic to be "do we
have  pair that cleanly resolve the current
conflicts?  If not, record a new preimage as a new variant", but
that does not happen at this stage yet.

Signed-off-by: Junio C Hamano