Change the grep_{lock,unlock} functions to assert that num_threads is
true, instead of only locking & unlocking the pthread mutex lock when
it is.
These functions are never called when num_threads isn't true, this
logic has gone through multiple iterations since the initial
introduction of grep threading in commit 5b594f457a ("Threaded grep",
2010-01-25), but ever since then they'd only be called if num_threads
was true, so this check made the code confusing to read.
Replace the check with an assertion, so that it's clear to the reader
that this code path is never taken unless we're spawning threads.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a warning about missing thread support when grep.threads or
--threads is set to a non 0 (default) or 1 (no parallelism) value
under NO_PTHREADS=YesPlease.
This is for consistency with the index-pack & pack-objects commands,
which also take a --threads option & are configurable via
pack.threads, and have long warned about the same under
NO_PTHREADS=YesPlease.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a buggy warning about threads under NO_PTHREADS=YesPlease. Due to
re-using the delta_search_threads variable for both the state of the
"pack.threads" config & the --threads option, setting "pack.threads"
but not supplying --threads would trigger the warning for both
"pack.threads" & --threads.
Solve this bug by resetting the delta_search_threads variable in
git_pack_config(), it might then be set by --threads again and be
subsequently warned about, as the test I'm changing here asserts.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a test for the warning that's emitted when --threads or
pack.threads is provided under NO_PTHREADS=YesPlease. This uses the
new PTHREADS prerequisite.
The assertion for C_LOCALE_OUTPUT in the latter test is currently
redundant, since unlike index-pack the pack-objects warnings aren't
i18n'd. However they might be changed to be i18n'd in the future, and
there's no harm in future-proofing the test.
There's an existing bug in the implementation of pack-objects which
this test currently tests for as-is. Details about the bug & the fix
are included in a follow-up change.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a PTHREADS prerequisite which is false when git is compiled with
NO_PTHREADS=YesPlease.
There's lots of custom code that runs when threading isn't available,
but before this prerequisite there was no way to test it.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the is_fixed() function which are currently only used in
compile_regexp() earlier so it can be used in the PCRE family of
functions in a later change.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the internal PCRE variable & function names to have a "1"
suffix. This is for preparation for libpcre2 support, where having
non-versioned names would be confusing.
An earlier change in this series ("grep: change the internal PCRE
macro names to be PCRE1", 2017-04-07) elaborates on the motivations
behind this change.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the internal USE_LIBPCRE define, & build options flag to use a
naming convention ending in PCRE1, without changing the long-standing
USE_LIBPCRE Makefile flag which enables this code.
This is for preparation for libpcre2 support where having things like
USE_LIBPCRE and USE_LIBPCRE2 in any more places than we absolutely
need to for backwards compatibility with old Makefile arguments would
be confusing.
In some ways it would be better to change everything that now uses
USE_LIBPCRE to use USE_LIBPCRE1, and to make specifying
USE_LIBPCRE (or --with-pcre) an error. This would impose a one-time
burden on packagers of git to s/USE_LIBPCRE/USE_LIBPCRE1/ in their
build scripts.
However I'd like to leave the door open to making
USE_LIBPCRE=YesPlease eventually mean USE_LIBPCRE2=YesPlease,
i.e. once PCRE v2 is ubiquitous enough that it makes sense to make it
the default.
This code and the USE_LIBPCRE Makefile argument was added in commit
63e7e9d8b6 ("git-grep: Learn PCRE", 2011-05-09). At the time there was
no indication that the PCRE project would release an entirely new &
incompatible API around 3 years later.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Factor the test for \0 in grep patterns into a function. Since commit
9eceddeec6 ("Use kwset in grep", 2011-08-21) any pattern containing a
\0 is considered fixed as regcomp() can't handle it.
This change makes later changes that make use of either has_null() or
is_fixed() (but not both) smaller.
While I'm at it make the comment conform to the style guide, i.e. add
an opening "/*\n".
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove redundant assignments to the "regflags" variable. This variable
is only used set under GREP_PATTERN_TYPE_ERE, so there's no need to
un-set it under GREP_PATTERN_TYPE_{FIXED,BRE,PCRE}.
Back in 5010cb5fcc[1], we did do "opt.regflags &= ~REG_EXTENDED" upon
seeing "-G" on the command line and flipped the bit on upon seeing
"-E", but I think that was perfectly sensible and it would have been a
bug if we didn't. They were part of the command line parsing that
could have seen "-E" on the command line earlier.
When cca2c172 ("git-grep: do not die upon -F/-P when
grep.extendedRegexp is set.", 2011-05-09) switched the command line
parsing to "read into a 'tentatively this is what we saw the last'
variable and then finally commit just once", we didn't touch
opt.regflags for PCRE and FIXED, but we still had to flip regflags
between BRE and ERE, because parsing of grep.extendedregexp
configuration variable directly touched opt.regflags back then, which
was done by b22520a3 ("grep: allow -E and -n to be turned on by
default via configuration", 2011-03-30).
When 84befcd0 ("grep: add a grep.patternType configuration setting",
2012-08-03) introduced extended_regexp_option field, we stopped
flipping regflags while reading the configuration, and that was when
we should have noticed and stopped dropping REG_EXTENDED bit in the
"now we can commit what type to use" helper function.
There is no reason to do this anymore, so stop doing it, more to
reduce "wait this is used under fixed/BRE/PCRE how?" confusion when
reading the code, than to to save ourselves trivial CPU cycles by
removing one assignment.
1. "built-in "git grep"", 2006-04-30.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a die(...) to a default case for the switch statement selecting
between grep pattern types under --recurse-submodules.
Normally this would be caught by -Wswitch, but the grep_pattern_type
type is converted to int by going through parse_options(). Changing
the argument type passed to compile_submodule_options() won't work,
the value will just get coerced. The -Wswitch-default warning will
warn about it, but that produces a lot of noise across the codebase,
this potential issue would be drowned in that noise.
Thus catching this at runtime is the least bad option. This won't ever
trigger in practice, but if a new pattern type were to be added this
catches an otherwise silent bug during development.
See commit 0281e487fd ("grep: optionally recurse into submodules",
2016-12-16) for the initial addition of this code.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a performance comparison test of grep regex engines given fixed
strings.
The current logic in compile_regexp() ignores the engine parameter and
uses kwset() to search for these, so this test shows no difference
between engines right now:
$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux ./run p7821-grep-engines-fixed.sh
[...]
Test this tree
------------------------------------------------
7821.1: fixed grep int 0.56(1.67+0.68)
7821.2: basic grep int 0.57(1.70+0.57)
7821.3: extended grep int 0.59(1.76+0.51)
7821.4: perl grep int 1.08(1.71+0.55)
7821.6: fixed grep uncommon 0.23(0.55+0.50)
7821.7: basic grep uncommon 0.24(0.55+0.50)
7821.8: extended grep uncommon 0.26(0.55+0.52)
7821.9: perl grep uncommon 0.24(0.58+0.47)
7821.11: fixed grep æ 0.36(1.30+0.42)
7821.12: basic grep æ 0.36(1.32+0.40)
7821.13: extended grep æ 0.38(1.30+0.42)
7821.14: perl grep æ 0.35(1.24+0.48)
Only when run with -i via GIT_PERF_7821_GREP_OPTS=' -i' do we avoid
avoid going through the same kwset.[ch] codepath, see the "Even when
-F..." comment in grep.c. This only kicks for the non-ASCII case:
$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_7821_GREP_OPTS=' -i' ./run p7821-grep-engines-fixed.sh
[...]
Test this tree
---------------------------------------------------
7821.1: fixed grep -i int 0.62(2.10+0.57)
7821.2: basic grep -i int 0.68(1.90+0.61)
7821.3: extended grep -i int 0.78(1.94+0.57)
7821.4: perl grep -i int 0.98(1.78+0.74)
7821.6: fixed grep -i uncommon 0.24(0.44+0.64)
7821.7: basic grep -i uncommon 0.25(0.56+0.54)
7821.8: extended grep -i uncommon 0.27(0.62+0.45)
7821.9: perl grep -i uncommon 0.24(0.59+0.49)
7821.11: fixed grep -i æ 0.30(0.96+0.39)
7821.12: basic grep -i æ 0.27(0.92+0.44)
7821.13: extended grep -i æ 0.28(0.90+0.46)
7821.14: perl grep -i æ 0.28(0.74+0.49)
I'm planning to change how fixed-string searching happens. This test
gives a baseline for comparing performance before & after any such
change.
See commit ("perf: add a comparison test of grep regex engines",
2017-04-19) for details on the machine the above test run was executed
on.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a very basic performance comparison test comparing the POSIX
basic, extended and perl engines.
In theory the "basic" and "extended" engines should be implemented
using the same underlying code with a slightly different pattern
parser, but some implementations may not do this. Jump through some
slight hoops to test both, which is worthwhile since "basic" is the
default.
Running this on an i7 3.4GHz Linux 4.9.0-2 Debian testing against a
checkout of linux.git & latest upstream PCRE, both PCRE and git
compiled with -O3 using gcc 7.1.1:
$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux ./run p7820-grep-engines.sh
[...]
Test this tree
---------------------------------------------------------------
7820.1: basic grep 'how.to' 0.34(1.24+0.53)
7820.2: extended grep 'how.to' 0.33(1.23+0.45)
7820.3: perl grep 'how.to' 0.31(1.05+0.56)
7820.5: basic grep '^how to' 0.32(1.24+0.42)
7820.6: extended grep '^how to' 0.33(1.20+0.44)
7820.7: perl grep '^how to' 0.57(2.67+0.42)
7820.9: basic grep '[how] to' 0.51(2.16+0.45)
7820.10: extended grep '[how] to' 0.49(2.20+0.43)
7820.11: perl grep '[how] to' 0.56(2.60+0.43)
7820.13: basic grep '\(e.t[^ ]*\|v.ry\) rare' 0.66(3.25+0.40)
7820.14: extended grep '(e.t[^ ]*|v.ry) rare' 0.65(3.19+0.46)
7820.15: perl grep '(e.t[^ ]*|v.ry) rare' 1.05(5.74+0.34)
7820.17: basic grep 'm\(ú\|u\)lt.b\(æ\|y\)te' 0.34(1.28+0.47)
7820.18: extended grep 'm(ú|u)lt.b(æ|y)te' 0.34(1.38+0.38)
7820.19: perl grep 'm(ú|u)lt.b(æ|y)te' 0.39(1.56+0.44)
Options can also be passed to git-grep via the GIT_PERF_7820_GREP_OPTS
environment variable. There are various modes such as "-v" that have
very different performance profiles, but handling the combinatorial
explosion of testing all those options would make this script much
more complex and harder to maintain. Instead just add the ability to
do one-shot runs with arbitrary options, e.g.:
$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_7820_GREP_OPTS=" -i" ./run p7820-grep-engines.sh
[...]
Test this tree
------------------------------------------------------------------
7820.1: basic grep -i 'how.to' 0.49(1.72+0.38)
7820.2: extended grep -i 'how.to' 0.46(1.64+0.42)
7820.3: perl grep -i 'how.to' 0.44(1.45+0.45)
7820.5: basic grep -i '^how to' 0.47(1.76+0.38)
7820.6: extended grep -i '^how to' 0.47(1.70+0.42)
7820.7: perl grep -i '^how to' 0.65(2.72+0.37)
7820.9: basic grep -i '[how] to' 0.86(3.64+0.42)
7820.10: extended grep -i '[how] to' 0.84(3.62+0.46)
7820.11: perl grep -i '[how] to' 0.73(3.06+0.39)
7820.13: basic grep -i '\(e.t[^ ]*\|v.ry\) rare' 1.63(8.13+0.36)
7820.14: extended grep -i '(e.t[^ ]*|v.ry) rare' 1.64(8.01+0.44)
7820.15: perl grep -i '(e.t[^ ]*|v.ry) rare' 1.44(6.88+0.44)
7820.17: basic grep -i 'm\(ú\|u\)lt.b\(æ\|y\)te' 0.66(2.67+0.44)
7820.18: extended grep -i 'm(ú|u)lt.b(æ|y)te' 0.66(2.67+0.43)
7820.19: perl grep -i 'm(ú|u)lt.b(æ|y)te' 0.59(2.31+0.37)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If we successfully parse a symref value like
"HEAD:refs/heads/master", we add the result to a string
list. But because the string list is marked
STRING_LIST_INIT_DUP, the string list code will make a copy
of the string and add the copy.
This patch fixes it by adding the entry with
string_list_append_nodup(), which lets the string list take
ownership of our newly allocated string. There are two
alternatives that seem like they would work, but aren't the
right solution.
The first is to initialize the list with the "NODUP"
initializer. That would avoid the copy, but then the string
list would not realize that it owns the strings. When we
eventually call string_list_clear(), it would not free the
strings, causing a leak.
The second option would be to use the normal
string_list_append(), but free the local copy in our
function. We can't do this because the local copy actually
contains _two_ strings; the symref name and its target. We
point to the target pointer via the "util" field, and its
memory must last as long as the string list does.
You may also wonder whether it's safe to ever free the local
copy, since the target points into it. The answer is yes,
because we duplicate it in annotaate_refs_with_symref_info
before clearing the string list.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On Windows, the remote repository name in, e.g., `git fetch foo\bar`
is clearly not a nickname for a configured remote repository. However,
the function valid_remote_nick() does not account for backslashes.
Use is_dir_sep() to check for both slashes and backslashes on Windows.
This was discovered while playing with Duy's patches that warn after
fopen() failures. The functions that read the branches and remotes
files are protected by a valid_remote_nick() check. Without this
change, a Windows style absolute path is incorrectly regarded as
nickname and is concatenated to a prefix and used with fopen(). This
triggers warnings because a colon in a path name is not allowed:
C:\Temp\gittest>git fetch C:\Temp\gittest
warning: unable to access '.git/remotes/C:\Temp\gittest': Invalid argument
warning: unable to access '.git/branches/C:\Temp\gittest': Invalid argument
From C:\Temp\gittest
* branch HEAD -> FETCH_HEAD
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The origin, entry, and scoreboard structures are core to the blame
interface and need to be exposed for blame functionality.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create function that populates a blame_entry and prepends it to a list.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create function that completes setting up blame_scoreboard structure.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create function that initializes blame_scoreboard to default values.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Either prepare_initial or prepare_final is used to determine which
commit is marked as 'final'. Call the underlying methods directly to
make this more clear.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The new method's interface is marginally cleaner than blame_sort, and
will avoid the need to expose the compare_blame_final method.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow the interface user to decide how to handle a progress update.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When iterating over references, reference priming is used to make sure
that loose references are read into the ref-cache before packed
references, to avoid races. It used to be that the prefix passed to
reference iterators almost always ended in `/`, for example
`refs/heads/`. In that case, the priming code would read all loose
references under `find_containing_dir("refs/heads/")`, which is
"refs/heads/". That's just what we want.
But now that `ref-filter` knows how to pass refname prefixes to
`for_each_fullref_in()`, the prefix might come from user input; for
example,
git for-each-ref refs/heads
Since the argument doesn't include a trailing slash, the reference
iteration code would prime all of the loose references under
`find_containing_dir("refs/heads")`, which is "refs/". Thus we would
unnecessarily read tags, remote-tracking references, etc., when the
user is only interested in branches.
It is a bit awkward to get around this problem. We can't just append a
slash to the argument, because we don't know ab initio whether an
argument like `refs/tags/release` corresponds to a single tag or to a
directory containing tags.
Moreover, until now a `prefix_ref_iterator` was used to make the final
decision about which references fall within the prefix (the
`cache_ref_iterator` only did a rough cut). This is also inefficient,
because the `prefix_ref_iterator` can't know, for example, that while
you are in a subdirectory that is completely within the prefix, you
don't have to do the prefix check.
So:
* Move the responsibility for doing the prefix check directly to
`cache_ref_iterator`. This means that `cache_ref_iterator_begin()`
never has to wrap its return value in a `prefix_ref_iterator`.
* Teach `cache_ref_iterator_begin()` (and `prime_ref_dir()`) to be
stricter about what they iterate over and what directories they
prime.
* Teach `cache_ref_iterator` to keep track of whether the current
`cache_ref_iterator_level` is fully within the prefix. If so, skip
the prefix checks entirely.
The main benefit of these optimizations is for loose references, since
packed references are always read all at once.
Note that after this change, `prefix_ref_iterator` is only ever used
for its trimming feature and not for its "prefix" feature. But I'm not
ripping out the latter yet, because it might be useful for another
patch series that I'm working on.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow the interface user to decide how to handle a failed sanity check,
whether that be to output with the current state or to do nothing.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The no_whole_file_rename flag is used in parts of blame that are being
moved to libgit, and should be accessible via the scoreboard structure.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The xdl_opts flags are used in parts of blame that are being moved to
libgit, and should be accessible via the scoreboard structure.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The show_root flag is used in parts of blame that are being moved to
libgit, and should be accessible via the scoreboard structure.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The reverse flag is used in parts of blame that are being moved to
libgit, and should be accessible via the scoreboard structure.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The argument from --contents is used in parts of blame that are being
moved to libgit, and should be accessible via the scoreboard structure.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Copy and move score thresholds are used in parts of blame that are being
moved to libgit, and should be accessible via the scoreboard structure.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Statistic counters are used in parts of blame that are being moved to
libgit, and should be accessible via the scoreboard structure.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Functions that will be publicly exposed should have names that better
reflect what they are a part of.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Functions that will be publicly exposed should have names that better
reflect what they are a part of.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Functions that will be publicly exposed should have names that better
reflect what they are a part of.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Functions related to blame_origin that will be publicly exposed should
have names that better reflect what they are a part of.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The scoreboard structure is core to the blame interface. Since
scoreboard will become more exposed, rename it to blame_scoreboard to
clarify what it is a part of.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The origin structure is core to the blame interface. Since origin will
become more exposed, rename it to blame_origin to clarify what it is a
part of.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
textconv_object is used in places other than blame.c and should be moved
to a more appropriate location. Other textconv related functions are
located in diff.c so that seems as good a place as any.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With commit 21666f1 ("convert object type handling from a string to a
number", 2007-02-26), there was no longer a need for blame.c to include
blob.h but it was not removed.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we diff a blob against a working tree file like:
git diff HEAD:Makefile Makefile
we always use the working tree filename for both sides of
the diff. In most cases that's fine, as the two would be the
same anyway, as above. And until recently, we used the
"name" for the blob, not the path, which would have the
messy "HEAD:" on the beginning.
But when they don't match, like:
git diff HEAD:old_path new_path
it makes sense to show both names.
This patch uses the blob's path field if it's available, and
otherwise falls back to using the filename (in preference to
the blob's name, which is likely to be garbage like a raw
sha1).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There's a subtle distinction between "name" and "path" for a
blob that we resolve: the name is what the user told us on
the command line, and the path is what we traversed when
finding the blob within a tree (if we did so).
When we diff blobs directly, we use "name", but "path" is
more likely to be useful to the user (it will find the
correct .gitattributes, and give them a saner diff header).
We still have to fall back to using the name for some cases
(i.e., any blob reference that isn't of the form tree:path).
That's the best we can do in such a case.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
