sha1_name.c: indentation fix

Signed-off-by: Junio C Hamano <gitster@pobox.com>
test-lib: reorder and include GIT-BUILD-OPTIONS a lot earlier

This dot-sources GIT-BUILD-OPTIONS a lot earlier in test-lib.sh so
that its use of "perl" can use "$PERL_PATH" to choose the version of
Perl the user told us is suitable for our use.

This is iffy; I didn't check it very carefully, and I would not be
surprised if there are subtle breakages.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: hide get_sha1_with_context_1() ugliness

There is no outside caller that cares about the "only-to-die" ugliness.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: get rid of get_sha1_with_mode_1()

The only external caller is setup.c that tries to give a nicer error
message when an object name is misspelt (e.g. "HEAD:cashe.h").
Retire it and give the caller a dedicated and more intuitive API
function maybe_die_on_misspelt_object_name().

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: get rid of get_sha1_with_mode()

There are only two callers, and they will benefit from being able to
pass disambiguation hints to underlying get_sha1_with_context() API
once it happens.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: clarify what "fake" is for in find_short_object_filename()

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: rename "now" to "current"

This variable points at the element we are currently looking at, and
does not have anything to do with the current time which the name
"now" implies.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: refactor find_short_packed_object()

Extract the logic to find object(s) that match a given prefix inside
a single pack into a separate helper function, and give it a bit more
comment.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: correct misnamed "canonical" and "res"

These are hexadecimal and binary representation of the short object
name given to the callchain as its input.  Rename them with _pfx
suffix to make it clear they are prefixes, and call them hex and bin
respectively.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: restructure disambiguation of short names

We try to find zero, one or more matches from loose objects and
packed objects independently and then decide if the given short
object name is unique across them.

Instead, introduce a "struct disambiguate_state" that keeps track of
what we have found so far, that can be one of:

 - We have seen one object that _could_ be what we are looking for;
 - We have also checked that object for additional constraints (if any),
   and found that the object satisfies it;
 - We have also checked that object for additional constraints (if any),
   and found that the object does not satisfy it; or
 - We have seen more than one objects that satisfy the constraints.

and pass it to the enumeration functions for loose and packed
objects.  The disambiguation state can optionally take a callback
function that takes a candidate object name and reports if the
object satisifies additional criteria (e.g. when the caller knows
that the short name must refer to a commit, this mechanism can be
used to check the type of the given object).

Compared to the earlier attempt, this round avoids the optional
check if there is only one candidate that matches the short name in
the first place.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
get_sha1(): fix error status regression

In finish_object_disambiguation(), if the candidate hasn't been
checked, there are two cases:

 - It is the first and only object that match the prefix; or
 - It replaced another object that matched the prefix but that
   object did not satisfy ds->fn() callback.

And the former case we set ds->candidate_ok to true without doing
anything else, while for the latter we check the candidate, which
may set ds->candidate_ok to false.

At this point in the code, ds->candidate_ok can be false only if
this last-round check found that the candidate does not pass the
check, because the state after update_candidates() returns cannot
satisfy

    !ds->ambiguous && ds->candidate_exists && ds->candidate_checked

and !ds->canidate_ok at the same time.

Hence, when we execute this "return", we know we have seen more than
one object that match the prefix (and none of them satisfied ds->fn),
meaning that we should say "the short name is ambiguous", not "there
is no object that matches the prefix".

Noticed by Jeff King.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: allow get_short_sha1() to take other flags

Instead of a separate "int quietly" argument, make it take "unsigned
flags" so that we can pass other options to it.

The bit assignment of this flag word is exposed in cache.h because
the mechanism will be exposed to callers of the higher layer in
later commits in this series.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: teach get_short_sha1() a commit-only option

When the caller knows that the parameter is meant to name a commit,
e.g. "56789a" in describe name "v1.2.3-4-g56789a", pass that as a
hint so that lower level can use it to disambiguate objects when
there is only one commit whose name begins with 56789a even if there
are objects of other types whose names share the same prefix.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
gitweb: Cleanup git_print_log()

When we see a signed-off-by line (and its friends), we set $signoff
to true, but then we process the next line after we are done without
giving control to the rest of the loop.  And when the line we saw is
not a signed-off-by line, we reset $signoff to false before running
the remainder of the loop.

Hence, the check for $signoff that attempts to remove an extra empty
line between two signed-off-by line was not doing anything useful.

Rename $empty to a more explicit name $skip_blank_line to tell us to
skip a blank line when we see one, set it after we see and emit a
blank line (to avoid showing more than one empty lines in a raw) or
after we handle a signed-off-by line (to avoid empty lines after
such a line), to fix this bug, and get rid of the $signoff variable
that is not useful.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
gitweb: Handle other types of tag in git_print_log

There are many types of tags used in S-o-b area [1].
Update the regex to handle them properly. It requires
the tag should be started by a capital letter and ended
by '-by: ' or '-By: '. The only exception is 'Cc: '.

[1] http://lwn.net/Articles/503829/

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
gitweb: Add support to Link: tag

The tip tree is the one of major subsystem tree in the
Linux kernel project. On the tip tree, the Link: (or
similar Buglink:) tag is used for tracking the original
discussion or context. Since it's ususally in the S-o-b
area, it'd be better using same style with others.

Also as it tends to contain a message-id sent from git
send-email, a part of the line would set a wrong hyperlink
like [1]. Fix it by not using format_log_line_html().

[1] git.kernel.org/?p=linux/kernel/git/tip/tip.git;a=commit;h=08942f6d5d992e9486b07653fd87ea8182a22fa0

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make <refname> documentation more consistent.

Formerly, the documentation for <refname> would occasionally say
<name> instead of <refname>. Now it uniformly uses <refname>.

Signed-off-by: Max Horn <max@quendi.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: get_describe_name() by definition groks only commits

Teach get_describe_name() to pass the disambiguation hint down the
callchain to get_short_sha1().

Also add tests to show various syntactic elements that we could take
advantage of the object type information to help disambiguration of
abbreviated object names.  Many of them are marked as broken, and
some of them will be fixed in later patches in this series.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: get_sha1_1() takes lookup flags

This is to pass the disambiguation hints from the caller down the
callchain.  Nothing is changed in this step, as everybody just
passes 0 in the flag.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c: many short names can only be committish

We know that the token "$name" that appear in "$name^{commit}",
"$name^4", "$name~4" etc. can only name a committish (either a
commit or a tag that peels to a commit).  Teach get_short_sha1() to
take advantage of that knowledge when disambiguating an abbreviated
SHA-1 given as an object name.

Signed-off-by: Junio C Hamano <gitster@pobox.com>