delta/git.git, branch ss/commit-squash-msg

commit: do not lose SQUASH_MSG contents

2016-03-21T22:32:24+00:00

When concluding a conflicted "git merge --squash", the command
failed to read SQUASH_MSG that was prepared by "git merge", and
showed only the "# Conflicts:" list of conflicted paths.

Place the contents from SQUASH_MSG at the beginning, just like we
show the commit log skeleton first when concluding a normal merge,
and then show the "# Conflicts:" list, to help the user write the
log message for the resulting commit.

Test by Junio C Hamano .

Signed-off-by: Sven Strickroth 
Signed-off-by: Junio C Hamano

memoize common git-path "constant" files

2015-08-10T22:37:14+00:00

One of the most common uses of git_path() is to pass a
constant, like git_path("MERGE_MSG"). This has two
drawbacks:

  1. The return value is a static buffer, and the lifetime
     is dependent on other calls to git_path, etc.

  2. There's no compile-time checking of the pathname. This
     is OK for a one-off (after all, we have to spell it
     correctly at least once), but many of these constant
     strings appear throughout the code.

This patch introduces a series of functions to "memoize"
these strings, which are essentially globals for the
lifetime of the program. We compute the value once, take
ownership of the buffer, and return the cached value for
subsequent calls.  cache.h provides a helper macro for
defining these functions as one-liners, and defines a few
common ones for global use.

Using a macro is a little bit gross, but it does nicely
document the purpose of the functions. If we need to touch
them all later (e.g., because we learned how to change the
git_dir variable at runtime, and need to invalidate all of
the stored values), it will be much easier to have the
complete list.

Note that the shared-global functions have separate, manual
declarations. We could do something clever with the macros
(e.g., expand it to a declaration in some places, and a
declaration _and_ a definition in path.c). But there aren't
that many, and it's probably better to stay away from
too-magical macros.

Likewise, if we abandon the C preprocessor in favor of
generating these with a script, we could get much fancier.
E.g., normalizing "FOO/BAR-BAZ" into "git_path_foo_bar_baz".
But the small amount of saved typing is probably not worth
the resulting confusion to readers who want to grep for the
function's definition.

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

get_repo_path: refactor path-allocation

2015-08-10T22:37:14+00:00

The get_repo_path function calls mkpath() and then does some
non-trivial operations on it, like calling
is_git_directory() and read_gitfile(). These are actually
OK (they do not use more pathname static buffers
themselves), but it takes a fair bit of work to verify.

Let's use our own strbuf to store the path, and we can
simply reuse it for each iteration of the loop (we can even
avoid rewriting the beginning part, since we are trying a
series of suffixes).

To make the strbuf cleanup easier, we split out a thin
wrapper. As a bonus, this wrapper can factor out the
canonicalization that happens in all of the early-return
code paths.

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

find_hook: keep our own static buffer

2015-08-10T22:37:13+00:00

The find_hook function returns the results of git_path,
which is a static buffer shared by other path-related calls.
Returning such a buffer is slightly dangerous, because it
can be overwritten by seemingly unrelated functions.

Let's at least keep our _own_ static buffer, so you can
only get in trouble by calling find_hook in quick
succession, which is less likely to happen and more obvious
to notice.

While we're at it, let's add some documentation of the
function's limitations.

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

refs.c: remove_empty_directories can take a strbuf

2015-08-10T22:37:13+00:00

The first thing we do in this function is copy the input
into a strbuf. Of the 4 callers, 3 of them already have a
strbuf we could use. Let's just take the strbuf, and convert
the remaining caller to use a strbuf, rather than a raw
git_path. This is safer, anyway, as remove_dir_recursively
is a non-trivial function that might use the pathname
buffers itself (this is _probably_ OK, as the likely culprit
would be calling resolve_gitlink_ref, but we do not pass the
proper flags to ask it to avoid blowing away gitlinks).

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

refs.c: avoid git_path assignment in lock_ref_sha1_basic

2015-08-10T22:37:13+00:00

Assigning the result of git_path is a bad pattern, because
it's not immediately obvious how long you expect the content
to stay valid (and it may be overwritten by subsequent
calls). Let's use a function-local strbuf here instead,
which we know is safe (we just have to remember to free it
in all code paths).

As a bonus, we get rid of a confusing variable-reuse
("ref_file" is used for two distinct purposes).

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

refs.c: avoid repeated git_path calls in rename_tmp_log

2015-08-10T22:37:13+00:00

Because it's not safe to store the static-buffer results of
git_path for a long time, we end up formatting the same
filename over and over. We can fix this by using a
function-local strbuf to store the formatted pathname and
avoid repeating ourselves.

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

refs.c: simplify strbufs in reflog setup and writing

2015-08-10T22:37:13+00:00

Commit 1a83c24 (git_snpath(): retire and replace with
strbuf_git_path(), 2014-11-30) taught log_ref_setup and
log_ref_write_1 to take a strbuf parameter, rather than a
bare string. It then makes an alias to the strbuf's "buf"
field under the original name.

This made the original diff much shorter, but the resulting
code is more complicated that it needs to be. Since we've
aliased the pointer, we drop our reference to the strbuf to
ensure we don't accidentally change it. But if we simply
drop our alias and use "logfile.buf" directly, we do not
have to worry about this aliasing. It's a larger diff, but
the resulting code is simpler.

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

path.c: drop git_path_submodule

2015-08-10T22:37:13+00:00

There are no callers of the slightly-dangerous static-buffer
git_path_submodule left. Let's drop it.

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

refs.c: remove extra git_path calls from read_loose_refs

2015-08-10T22:37:13+00:00

In iterating over the loose refs in "refs/foo/", we keep a
running strbuf with "refs/foo/one", "refs/foo/two", etc. But
we also need to access these files in the filesystem, as
".git/refs/foo/one", etc. For this latter purpose, we make a
series of independent calls to git_path(). These are safe
(we only use the result to call stat()), but assigning the
result of git_path is a suspicious pattern that we'd rather
avoid.

This patch keeps a running buffer with ".git/refs/foo/", and
we can just append/reset each directory element as we loop.
This matches how we handle the refnames. It should also be
more efficient, as we do not keep formatting the same
".git/refs/foo" prefix (which can be arbitrarily deep).

Technically we are dropping a call to strbuf_cleanup() on
each generated filename, but that's OK; it wasn't doing
anything, as we are putting in single-level names we read
from the filesystem (so it could not possibly be cleaning up
cruft like "./" in this instance).

A clever reader may also note that the running refname
buffer ("refs/foo/") is actually a subset of the filesystem
path buffer (".git/refs/foo/"). We could get by with one
buffer, indexing the length of $GIT_DIR when we want the
refname. However, having tried this, the resulting code
actually ends up a little more confusing, and the efficiency
improvement is tiny (and almost certainly dwarfed by the
system calls we are making).

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano