On top of optimization by Linus not to ask refs that already match, we
can walk our refs and not issue "want" for things that are known to be
reachable from them.
Signed-off-by: Junio C Hamano <junkio@cox.net>
If everything is up-to-date locally, we don't need to even ask for a
pack-file from the remote, or try to unpack it.
This is especially important for tags - since the pack-file common commit
logic is based purely on the commit history, it will never be able to find
a common tag, and will thus always end up re-fetching them.
Especially notably, if the tag points to a non-commit (eg a tagged tree),
the pack-file would be unnecessarily big, just because it cannot any most
recent common point between commits for pruning.
Short-circuiting the case where we already have that reference means that
we avoid a lot of these in the common case.
NOTE! This only matches remote ref names against the same local name,
which works well for tags, but is not as generic as it could be. If we
ever need to, we could match against _any_ local ref (if we have it, we
have it), but this "match against same name" is simpler and more
efficient, and covers the common case.
Renaming of refs is common for branch heads, but since those are always
commits, the pack-file generation can optimize that case.
In some cases we might still end up fetching pack-files unnecessarily, but
this at least avoids the re-fetching of tags over and over if you use a
regular
git fetch --tags ...
which was the main reason behind the change.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This allows the remote side (most notably, upload-pack) to show
additional information without affecting the downloader. Peek-remote
does not ignore them -- this is to make it useful for Pasky's
automatic tag following.
Signed-off-by: Junio C Hamano <junkio@cox.net>
This is a beginning of resurrecting the multi-head pulling support
for git-fetch-pack command. The git-fetch-script wrapper still
only knows about fetching a single head, without renaming, so it is
not very useful unless you directly call git-fetch-pack itself yet.
It also fixes a longstanding obsolete description of how the command
discovers the list of local commits.
This adds documentation for 'smarter pull' family of commands.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oh, well.. FC4 has UTF-8 as the default environment, and I applaud
that, but then it sometimes results in these characters that aren't
actually visible as a problem.
"git_path()" returns a static pathname pointer into the git directory
using a printf-like format specifier.
"head_ref()" works like "for_each_ref()", except for just the HEAD.
It returns the result SHA1 on stdout, so you can do
remote=$(git-fetch-pack host:dir branchname)
and it will unpack the objects and "remote" will be the SHA1 name of the
branch on the other side. You can then save that off, or merge it, or
whatever.
It's meant to be used by "git fetch" for the local and ssh case.
It doesn't actually do the fetching now, but it does discover the common
commit point.
