rev-list --bisect is used by git bisect, but never together with
--first-parent. Because rev-list --bisect together with --first-parent
is not handled currently, and even leads to segfaults, refuse to use
both options together.

Because this is not supported, it makes little sense to use git log
--bisect --first parent either, because refs/heads/bad is not limited to
the first parent chain.
Helped-by: NJunio C. Hamano <gitster@pobox.com>
Helped-by: NEric Sunshine <sunshine@sunshineco.com>
Signed-off-by: NKevin Daudt <me@ikke.info>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Because "--graph" is about connected history while --no-walk is
about discrete points, it does not make sense to allow these two
options at the same time. [1]

This change makes a few calls to "show --graph" fail in t4052, but
asking to show one commit with graph is a nonsensical thing to do.
Thus, tests on "show --graph" in t4052 have been removed [2,3].
Same tests on "show" without --graph option have already been tested
in 4052.

3 testcases have been added to test this patch.

[1]: http://article.gmane.org/gmane.comp.version-control.git/216083
[2]: http://article.gmane.org/gmane.comp.version-control.git/264950
[3]: http://article.gmane.org/gmane.comp.version-control.git/265107Helped-By: NEric Sunshine <sunshine@sunshineco.com>
Helped-By: NRené Scharfe <l.s.r@web.de>
Helped-By: NJunio C Hamano <gitster@pobox.com>
Signed-off-by: NDongcan Jiang <dongcan.jiang@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

No external callers exist.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

"git log --grep=<string>" shows only commits with messages that
match the given string, but sometimes it is useful to be able to
show only commits that do *not* have certain messages (e.g. "show
me ones that are not FIXUP commits").

Originally, we had the invert-grep flag in grep_opt, but because
"git grep --invert-grep" does not make sense except in conjunction
with "--files-with-matches", which is already covered by
"--files-without-matches", it was moved it to revisions structure.
To have the flag there expresses the function to the feature better.

When the newly inserted two tests run, the history would have commits
with messages "initial", "second", "third", "fourth", "fifth", "sixth"
and "Second", committed in this order.  The commits that does not match
either "th" or "Sec" is "second" and "initial". For the case insensitive
case only "initial" matches.
Signed-off-by: NChristoph Junghans <ottxor@gentoo.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In commit fbd4a703 (list-objects: mark more commits as edges in
mark_edges_uninteresting - 2013-08-16), we marked an increasing number
of edges uninteresting.  This change, and the subsequent change to make
this conditional on --objects-edge, are used by --thin to make much
smaller packs for shallow clones.

Unfortunately, they cause a significant performance regression when
pushing non-shallow clones with lots of refs (23.322 seconds vs.
4.785 seconds with 22400 refs).  Add an option to git rev-list,
--objects-edge-aggressive, that preserves this more aggressive behavior,
while leaving --objects-edge to provide more performant behavior.
Preserve the current behavior for the moment by using the aggressive
option.
Signed-off-by: Nbrian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The callers of get_merge_bases() can choose to leave object flags
used during the merge-base traversal by passing cleanup=0 as a
parameter, but in practice a very few callers can afford to do so
(namely, "git merge-base"), as they need to compute merge base in
preparation for other processing of their own and they need to see
the object without contaminate flags.

Change the function signature of get_merge_bases_many() and
get_merge_bases() to drop the cleanup parameter, so that the
majority of the callers do not have to say ", 1" at the end.

Give a new get_merge_bases_many_dirty() API to support only a few
callers that know they do not need to spend cycles cleaning up the
object flags.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NRamsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There is currently no easy way to ask the revision traversal
machinery to include objects reachable from the index (e.g.,
blobs and trees that have not yet been committed). This
patch adds an option to do so.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we call traverse_commit_list, we may have trees and
blobs in the pending array. As we process these, we pass the
"name" field from the pending entry as the path of the
object within the tree (which then becomes the root path if
we recurse into subtrees).

When we set up the traversal in prepare_revision_walk,
though, the "name" field of any pending trees and blobs is
likely to be the ref at which we found the object. We would
not want to make this part of the path (e.g., doing so would
make "git rev-list --objects v2.6.11-tree" in linux.git show
paths like "v2.6.11-tree/Makefile", which is nonsensical).
Therefore prepare_revision_walk sets the name field of each
pending tree and blobs to the empty string.

However, this leaves no room for a caller who does know the
correct path of a pending object to propagate that
information to the revision walker. We can fix this by
making two related changes:

  1. Use the "path" field as the path instead of the "name"
     field in traverse_commit_list. If the path is not set,
     default to "" (which is what we always ended up with in
     the current code, because of prepare_revision_walk).

  2. In prepare_revision_walk, make a complete copy of the
     entry. This makes the path field available to the
     walker (if there is one), solving our problem.
     Leaving the name field intact is now OK, as we do not
     use it as a path due to point (1) above (and we can use
     it to make more meaningful error messages if we want).
     We also make the original "mode" field available to the
     walker, though it does not actually use it.

Note that we still re-add the pending objects and free the
old ones (so we may strdup the path and name only to free
the old ones). This could be made more efficient by simply
copying the object_array entries that we are keeping.
However, that would require more restructuring of the code,
and is not done here.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We want to add all reflog entries as tips for finding
reachable objects. The revision machinery can already do
this (to support "rev-list --reflog"); we can reuse that
code.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we enter prepare_revision_walk, we have zero or more
entries in our "pending" array. We disconnect that array
from the rev_info, and then process each entry:

  1. If the entry is a commit and the --source option is in
     effect, we keep a pointer to the object name.

  2. Otherwise, we re-add the item to the pending list with
     a blank name.

We then throw away the old array by freeing the array
itself, but do not touch the "name" field of each entry. For
any items of type (2), we leak the memory associated with
the name. This commit fixes that by calling object_array_clear,
which handles the cleanup for us.

That breaks (1), though, because it depends on the memory
pointed to by the name to last forever. We can solve that by
making a copy of the name. This is slightly less efficient,
but it shouldn't matter in practice, as we do it only for
the tip commits of the traversal.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NRene Scharfe <l.s.r@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In the previous commit, we made add_name_decoration global
so that adders would not have to access the hash directly.
We now make the hash itself static so that callers _have_ to
add through our function, making sure that all additions go
through a single point.  To do this, we have to add one more
accessor function: a way to lookup entries in the hash.

Since the only caller doesn't actually look at the returned
value, but rather only asks whether there is a decoration or
not, we could provide only a boolean "has_name_decoration".
That would allow us to make "struct name_decoration" local
to log-tree, as well.

However, it's unlikely to cause any maintainability harm
making the actual data public, and this interface is more
flexible if we need to look at decorations from other parts
of the code in the future.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Once upon a time, we parsed pretty options by looking for
"--pretty" at the start of the string, and then feeding the
rest (including an "=") to get_commit_format. Later, commit
48ded916 (log --pretty: do not accept bogus "--prettyshort",
2008-05-25) split this into a separate check for "--pretty"
versus "--pretty=".

However, when parsing "--pretty", we still passed "arg+8" to
get_commit_format. This is useless, since it will always
point to the NUL terminator at the end of the string. We can
simply pass NULL instead; both parameters are treated the
same by get_commit_format.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Like the callsites in the previous commit, logmsg_reencode
already falls back to read_sha1_file when necessary.
However, I split its conversion out into its own commit
because it's a bit more complex.

We return either:

  1. The original commit->buffer

  2. A newly allocated buffer from read_sha1_file

  3. A reencoded buffer (based on either 1 or 2 above).

while trying to do as few extra reads/allocations as
possible. Callers currently free the result with
logmsg_free, but we can simplify this by pointing them
straight to unuse_commit_buffer. This is a slight layering
violation, in that we may be passing a buffer from (3).
However, since the end result is to free() anything except
(1), which is unlikely to change, and because this makes the
interface much simpler, it's a reasonable bending of the
rules.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The return value from logmsg_reencode may be either a newly
allocated buffer or a pointer to the existing commit->buffer.
We would not want the caller to accidentally free() or
modify the latter, so let's mark it as const.  We can cast
away the constness in logmsg_free, but only once we have
determined that it is a free-able buffer.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This mistyped command line simply ignores "master" and ends up
showing two commits from the current HEAD:

    $ git log -2master

because we feed "2master" to atoi() without making sure that the
whole string is parsed as an integer.

Use the strtol_i() helper function instead.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

These two commands are supposed to be equivalent:

  $ git log --exclude=refs/notes/\* --all --no-merges --since=2.days |
    git shortlog
  $ git shortlog --exclude=refs/notes/\* --all --no-merges --since=2.days

However, the latter does not understand the ref-exclusion command
line option, even though other options understood by "log", such as
"--all" and "--no-merges", are understood.

This was because e7b432c5 (revision: introduce --exclude=<glob> to
tame wildcards, 2013-08-30) did not wire the new option fully to the
machinery.  A new option understood by handle_revision_pseudo_opt()
must be told to handle_revision_opt() as well.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When pack-objects is computing the reachability bitmap to
serve a fetch request, it can erroneously die() if some of
the UNINTERESTING objects are not present. Upload-pack
throws away HAVE lines from the client for objects we do not
have, but we may have a tip object without all of its
ancestors (e.g., if the tip is no longer reachable and was
new enough to survive a `git prune`, but some of its
reachable objects did get pruned).

In the non-bitmap case, we do a revision walk with the HAVE
objects marked as UNINTERESTING. The revision walker
explicitly ignores errors in accessing UNINTERESTING commits
to handle this case (and we do not bother looking at
UNINTERESTING trees or blobs at all).

When we have bitmaps, however, the process is quite
different.  The bitmap index for a pack-objects run is
calculated in two separate steps:

First, we perform an extensive walk from all the HAVEs to
find the full set of objects reachable from them. This walk
is usually optimized away because we are expected to hit an
object with a bitmap during the traversal, which allows us
to terminate early.

Secondly, we perform an extensive walk from all the WANTs,
which usually also terminates early because we hit a commit
with an existing bitmap.

Once we have the resulting bitmaps from the two walks, we
AND-NOT them together to obtain the resulting set of objects
we need to pack.

When we are walking the HAVE objects, the revision walker
does not know that we are walking it only to mark the
results as uninteresting. We strip out the UNINTERESTING flag,
because those objects _are_ interesting to us during the
first walk. We want to keep going to get a complete set of
reachable objects if we can.

We need some way to tell the revision walker that it's OK to
silently truncate the HAVE walk, just like it does for the
UNINTERESTING case. This patch introduces a new
`ignore_missing_links` flag to the `rev_info` struct, which
we set only for the HAVE walk.

It also adds tests to cover UNINTERESTING objects missing
from several positions: a missing blob, a missing tree, and
a missing parent commit. The missing blob already worked (as
we do not care about its contents at all), but the other two
cases caused us to die().

Note that there are a few cases we do not need to test:

  1. We do not need to test a missing tree, with the blob
     still present. Without the tree that refers to it, we
     would not know that the blob is relevant to our walk.

  2. We do not need to test a tip commit that is missing.
     Upload-pack omits these for us (and in fact, we
     complain even in the non-bitmap case if it fails to do
     so).
Reported-by: NSiddharth Agarwal <sid0@fb.com>
Signed-off-by: NVicent Marti <tanoku@gmail.com>
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Option explanation is in rev-list-options.txt. The interaction with -z
is left undecided.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is the "rev-list" analogue to 25fba78d (cat-file:
disable object/refname ambiguity check for batch mode,
2013-07-12).  Like cat-file, "rev-list --stdin" may read a
large number of sha1 object names, and the warning check
introduces a significant slow-down.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This helps reduce the number of match_pathspec_depth() call sites and
show how match_pathspec_depth() is used.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Make it clear that we don't use fnmatch() anymore.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Since diff_tree_sha1() can now accept empty trees via NULL sha1, we
could just call it without manually reading trees into tree_desc and
duplicating code.

Besides, that

	if (!tree)
		return 0;

looked suspect - we were saying an invalid tree != empty tree, but maybe it is
better to just say the tree is invalid here, which is what diff_tree_sha1()
does for such case.
Signed-off-by: NKirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

With the previous fix 895c5ba3 (revision: do not peel tags used in
range notation, 2013-09-19), handle_revision_arg() that processes
command line arguments for the "git log" family of commands no
longer directly places the object pointed by the tag in the pending
object array when it sees a tag object.  We used to place pointee
there after copying the flag bits like UNINTERESTING and
SYMMETRIC_LEFT.

This change meant that any flag that is relevant to later history
traversal must now be propagated to the pointed objects (most often
these are commits) while starting the traversal, which is partly
done by handle_commit() that is called from prepare_revision_walk().
We did propagate UNINTERESTING, but did not do so for others, most
notably SYMMETRIC_LEFT.  This caused "git log --left-right v1.0..."
(where "v1.0" is a tag) to start losing the "leftness" from the
commit the tag points at.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

"git rev-list --objects ^A^{tree} B^{tree}" ought to mean "I want a
list of objects inside B's tree, but please exclude the objects that
appear inside A's tree".

we see the top-level tree marked as uninteresting (i.e. ^A^{tree} in
the above example) and call mark_tree_uninteresting() on it; this
unfortunately prevents us from recursing into the tree and marking
the objects in the tree as uninteresting.

The reason why "git log ^A A" yields an empty set of commits,
i.e. we do not have a similar issue for commits, is because we call
mark_parents_uninteresting() after seeing an uninteresting commit.
The uninteresting-ness of the commit itself does not prevent its
parents from being marked as uninteresting.

Introduce mark_tree_contents_uninteresting() and structure the code
in handle_commit() in such a way that it makes it the responsibility
of the callchain leading to this function to mark commits, trees and
blobs as uninteresting, and also make it the responsibility of the
helpers called from this function to mark objects that are reachable
from them.

Note that this is a very old bug that probably dates back to the day
when "rev-list --objects" was introduced.  The line to clear
tree->object.parsed at the end of mark_tree_contents_uninteresting()
can be removed when this fix is merged to the codebase after
6e454b9a (clear parsed flag when we free tree buffers, 2013-06-05).
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Leaving only the function definitions and declarations so that any
new topic in flight can still make use of the old functions, replace
existing uses of the prefixcmp() and suffixcmp() with new API
functions.

The change can be recreated by mechanically applying this:

    $ git grep -l -e prefixcmp -e suffixcmp -- \*.c |
      grep -v strbuf\\.c |
      xargs perl -pi -e '
        s|!prefixcmp\(|starts_with\(|g;
        s|prefixcmp\(|!starts_with\(|g;
        s|!suffixcmp\(|ends_with\(|g;
        s|suffixcmp\(|!ends_with\(|g;
      '

on the result of preparatory changes in this series.
Signed-off-by: NChristian Couder <chriscool@tuxfamily.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

... while updating their function signature.  To be squashed into
the initial patch to rev-list.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NFelipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Normally parse_pathspec() is used on command line arguments where it
can do fancy thing like parsing magic on each argument or adding magic
for all pathspecs based on --*-pathspecs options.

There's another use of parse_pathspec(), where pathspec is needed, but
the input is known to be pure paths. In this case we usually don't
want --*-pathspecs to interfere. And we definitely do not want to
parse magic in these paths, regardless of --literal-pathspecs.

Add new flag PATHSPEC_LITERAL_PATH for this purpose. When it's set,
--*-pathspecs are ignored, no magic is parsed. And if the caller
allows PATHSPEC_LITERAL (i.e. the next calls can take literal magic),
then PATHSPEC_LITERAL will be set.

This fixes cases where git chokes when GIT_*_PATHSPECS are set because
parse_pathspec() indicates it won't take any magic. But
GIT_*_PATHSPECS add them anyway. These are

   export GIT_LITERAL_PATHSPECS=1
   git blame -- something
   git log --follow something
   git log --merge

"git ls-files --with-tree=path" (aka parse_pathspec() in
overlay_tree_on_cache()) is safe because the input is empty, and
producing one pathspec due to PATHSPEC_PREFER_CWD does not take any
magic into account.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This commit enables users of `struct rev_info` to peform custom limiting
during a revision walk (i.e. `get_revision`).

If the field `include_check` has been set to a callback, this callback
will be issued once for each commit before it is added to the "pending"
list of the revwalk. If the include check returns 0, the commit will be
marked as added but won't be pushed to the pending list, effectively
limiting the walk.
Signed-off-by: NVicent Marti <tanoku@gmail.com>
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When parse_pathspec() is called with no paths, the behavior could be
either return no paths, or return one path that is cwd. Some commands
do the former, some the latter. parse_pathspec() itself does not make
either the default and requires the caller to specify either flag if
it may run into this situation.

I've grep'd through all parse_pathspec() call sites. Some pass
neither, but those are guaranteed never pass empty path to
parse_pathspec(). There are two call sites that may pass empty path
and are fixed with this patch.

[jc: added a test from Antoine's bug report]
Reported-by: NAntoine Pelisse <apelisse@gmail.com>
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

A range notation "A..B" means exactly the same thing as what "^A B"
means, i.e. the set of commits that are reachable from B but not
from A.  But the internal representation after the revision parser
parsed these two notations are subtly different.

 - "rev-list ^A B" leaves A and B in the revs->pending.objects[]
   array, with the former marked as UNINTERESTING and the revision
   traversal machinery propagates the mark to underlying commit
   objects A^0 and B^0.

 - "rev-list A..B" peels tags and leaves A^0 (marked as
   UNINTERESTING) and B^0 in revs->pending.objects[] array before
   the traversal machinery kicks in.

This difference usually does not matter, but starts to matter when
the --objects option is used.  For example, we see this:

    $ git rev-list --objects v1.8.4^1..v1.8.4 | grep $(git rev-parse v1.8.4)
    $ git rev-list --objects v1.8.4 ^v1.8.4^1 | grep $(git rev-parse v1.8.4)
    04f013dc38d7512eadb915eba22efc414f18b869 v1.8.4

With the former invocation, the revision traversal machinery never
hears about the tag v1.8.4 (it only sees the result of peeling it,
i.e. the commit v1.8.4^0), and the tag itself does not appear in the
output.  The latter does send the tag object itself to the output.

Make the range notation keep the unpeeled objects and feed them to
the traversal machinery to fix this inconsistency.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is useful to make sure we don't step outside the boundaries of what
we are interpreting at the moment. For example while interpreting
foobar@{u}~1, the job of interpret_branch_name() ends right before ~1,
but there's no way to figure that out inside the function, unless the
len argument is passed.

So let's do that.
Signed-off-by: NFelipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

People often find "git log --branches" etc. that includes _all_
branches is cumbersome to use when they want to grab most but except
some.  The same applies to --tags, --all and --glob.

Teach the revision machinery to remember patterns, and then upon the
next such a globbing option, exclude those that match the pattern.

With this, I can view only my integration branches (e.g. maint,
master, etc.) without topic branches, which are named after two
letters from primary authors' names, slash and topic name.

    git rev-list --no-walk --exclude=??/* --branches |
    git name-rev --refs refs/heads/* --stdin

This one shows things reachable from local and remote branches that
have not been merged to the integration branches.

    git log --remotes --branches --not --exclude=??/* --branches

It may be a bit rough around the edges, in that the pattern to give
the exclude option depends on what globbing option follows.  In
these examples, the pattern "??/*" is used, not "refs/heads/??/*",
because the globbing option that follows the -"-exclude=<pattern>"
is "--branches".  As each use of globbing option resets previously
set "--exclude", this may not be such a bad thing, though.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The reflog walking logic (git log -g) replaces the true parent list
with the preceding commit in the reflog.  This results in bogus commit
diffs when combined with options such as -p; the diff is against the
reflog predecessor, not the parent of the commit.

Save the true parents on the side, extending the functions from the
previous commit.  The diff logic picks them up and uses them to show
the correct diffs.

We do have to be somewhat careful about repeated calling of
save_parents(), since the reflog may list a commit more than once.  We
now store (commit_list*)-1 to distinguish the "not saved yet" and
"root commit" cases.  This lets us preserve an empty parent list even
if save_parents() is repeatedly called.
Suggested-by: NJeff King <peff@peff.net>
Signed-off-by: NThomas Rast <trast@inf.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When using pathspec filtering in combination with diff-based log
output, parent simplification happens before the diff is computed.
The diff is therefore against the *simplified* parents.

This works okay, arguably by accident, in the normal case:
simplification reduces to one parent as long as the commit is TREESAME
to it.  So the simplified parent of any given commit must have the
same tree contents on the filtered paths as its true (unfiltered)
parent.

However, --full-diff breaks this guarantee, and indeed gives pretty
spectacular results when comparing the output of

  git log --graph --stat ...
  git log --graph --full-diff --stat ...

(--graph internally kicks in parent simplification, much like
--parents).

To fix it, store a copy of the parent list before simplification (in a
slab) whenever --full-diff is in effect.  Then use the stored parents
instead of the simplified ones in the commit display code paths.  The
latter do not actually check for --full-diff to avoid duplicated code;
they just grab the original parents if save_parents() has not been
called for this revision walk.

For ordinary commits it should be obvious that this is the right thing
to do.

Merge commits are a bit subtle.  Observe that with default
simplification, merge simplification is an all-or-nothing decision:
either the merge is TREESAME to one parent and disappears, or it is
different from all parents and the parent list remains intact.
Redundant parents are not pruned, so the existing code also shows them
as a merge.

So if we do show a merge commit, the parent list just consists of the
rewrite result on each parent.  Running, e.g., --cc on this in
--full-diff mode is not very useful: if any commits were skipped, some
hunks will disagree with all sides of the merge (with one side,
because commits were skipped; with the others, because they didn't
have those changes in the first place).  This triggers --cc showing
these hunks spuriously.

Therefore I believe that even for merge commits it is better to show
the diffs wrt. the original parents.
Reported-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Helped-by: NJunio C Hamano <gitster@pobox.com>
Helped-by: NRamsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: NThomas Rast <trast@inf.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

While at there, move free_pathspec() to pathspec.c
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

These call sites follow the pattern:

   paths = get_pathspec(prefix, argv);
   init_pathspec(&pathspec, paths);

which can be converted into a single parse_pathspec() call.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>