Suppose a fetch or push is requested between two shallow repositories
(with no history deepening or shortening). A pack that contains
necessary objects is transferred over together with .git/shallow of
the sender. The receiver has to determine whether it needs to update
.git/shallow if new refs needs new shallow comits.
The rule here is avoid updating .git/shallow by default. But we don't
want to waste the received pack. If the pack contains two refs, one
needs new shallow commits installed in .git/shallow and one does not,
we keep the latter and reject/warn about the former.
Even if .git/shallow update is allowed, we only add shallow commits
strictly necessary for the former ref (remember the sender can send
more shallow commits than necessary) and pay attention not to
accidentally cut the receiver history short (no history shortening is
asked for)
So the steps to figure out what ref need what new shallow commits are:
1. Split the sender shallow commit list into "ours" and "theirs" list
by has_sha1_file. Those that exist in current repo in "ours", the
remaining in "theirs".
2. Check the receiver .git/shallow, remove from "ours" the ones that
also exist in .git/shallow.
3. Fetch the new pack. Either install or unpack it.
4. Do has_sha1_file on "theirs" list again. Drop the ones that fail
has_sha1_file. Obviously the new pack does not need them.
5. If the pack is kept, remove from "ours" the ones that do not exist
in the new pack.
6. Walk the new refs to answer the question "what shallow commits,
both ours and theirs, are required in .git/shallow in order to add
this ref?". Shallow commits not associated to any refs are removed
from their respective list.
7. (*) Check reachability (from the current refs) of all remaining
commits in "ours". Those reachable are removed. We do not want to
cut any part of our (reachable) history. We only check up
commits. True reachability test is done by
check_everything_connected() at the end as usual.
8. Combine the final "ours" and "theirs" and add them all to
.git/shallow. Install new refs. The case where some hook rejects
some refs on a push is explained in more detail in the push
patches.
Of these steps, #6 and #7 are expensive. Both require walking through
some commits, or in the worst case all commits. And we rather avoid
them in at least common case, where the transferred pack does not
contain any shallow commits that the sender advertises. Let's look at
each scenario:
1) the sender has longer history than the receiver
All shallow commits from the sender will be put into "theirs" list
at step 1 because none of them exists in current repo. In the
common case, "theirs" becomes empty at step 4 and exit early.
2) the sender has shorter history than the receiver
All shallow commits from the sender are likely in "ours" list at
step 1. In the common case, if the new pack is kept, we could empty
"ours" and exit early at step 5.
If the pack is not kept, we hit the expensive step 6 then exit
after "ours" is emptied. There'll be only a handful of objects to
walk in fast-forward case. If it's forced update, we may need to
walk to the bottom.
3) the sender has same .git/shallow as the receiver
This is similar to case 2 except that "ours" should be emptied at
step 2 and exit early.
A fetch after "clone --depth=X" is case 1. A fetch after "clone" (from
a shallow repo) is case 3. Luckily they're cheap for the common case.
A push from "clone --depth=X" falls into case 2, which is expensive.
Some more work may be done at the sender/client side to avoid more
work on the server side: if the transferred pack does not contain any
shallow commits, send-pack should not send any shallow commits to the
receive-pack, effectively turning it into a normal push and avoid all
steps.
This patch implements all steps except #3, already handled by
fetch-pack and receive-pack, #6 and #7, which has their own patch due
to their size.
(*) in previous versions step 7 was put before step 3. I reorder it so
that the common case that keeps the pack does not need to walk
commits at all. In future if we implement faster commit
reachability check (maybe with the help of pack bitmaps or commit
cache), step 7 could become cheap and be moved up before 6 again.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For most of our functions that take printf-like formats, we
use gcc's __attribute__((format)) to get compiler warnings
when the functions are misused. Let's give a few more
functions the same protection.
In most cases, the annotations do not uncover any actual
bugs; the only code change needed is that we passed a size_t
to transfer_debug, which expected an int. Since we expect
the passed-in value to be a relatively small buffer size
(and cast a similar value to int directly below), we can
just cast away the problem.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix warnings from 'make check'.
- These files don't include 'builtin.h' causing sparse to complain that
cmd_* isn't declared:
builtin/clone.c:364, builtin/fetch-pack.c:797,
builtin/fmt-merge-msg.c:34, builtin/hash-object.c:78,
builtin/merge-index.c:69, builtin/merge-recursive.c:22
builtin/merge-tree.c:341, builtin/mktag.c:156, builtin/notes.c:426
builtin/notes.c:822, builtin/pack-redundant.c:596,
builtin/pack-refs.c:10, builtin/patch-id.c:60, builtin/patch-id.c:149,
builtin/remote.c:1512, builtin/remote-ext.c:240,
builtin/remote-fd.c:53, builtin/reset.c:236, builtin/send-pack.c:384,
builtin/unpack-file.c:25, builtin/var.c:75
- These files have symbols which should be marked static since they're
only file scope:
submodule.c:12, diff.c:631, replace_object.c:92, submodule.c:13,
submodule.c:14, trace.c:78, transport.c:195, transport-helper.c:79,
unpack-trees.c:19, url.c:3, url.c:18, url.c:104, url.c:117, url.c:123,
url.c:129, url.c:136, thread-utils.c:21, thread-utils.c:48
- These files redeclare symbols to be different types:
builtin/index-pack.c:210, parse-options.c:564, parse-options.c:571,
usage.c:49, usage.c:58, usage.c:63, usage.c:72
- These files use a literal integer 0 when they really should use a NULL
pointer:
daemon.c:663, fast-import.c:2942, imap-send.c:1072, notes-merge.c:362
While we're in the area, clean up some unused #includes in builtin files
(mostly exec_cmd.h).
Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
You no longer get this output with GIT_TRACE=1; instead, you
can do GIT_TRACE_SETUP=1.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If you happen to have a strbuf, it is a little more readable
and a little more efficient to be able to print it directly
instead of jamming it through the trace_printf interface.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we add more tracing areas, this will avoid repeated code.
Technically, trace_printf already checks this and will avoid
printing if the trace key is not set. However, callers may
want to find out early whether or not tracing is enabled so
they can avoid doing work in the common non-trace case.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Right now you turn all tracing off and on with GIT_TRACE. To
support new types of tracing without forcing the user to see
all of them, we will soon support turning each tracing area
on with GIT_TRACE_*.
This patch lays the groundwork by providing an interface
which does not assume GIT_TRACE. However, we still maintain
the trace_printf interface so that existing callers do not
need to be refactored.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is a necessary cleanup to adding new types of trace
functions.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a variable-args function, the code for writing into a strbuf is
non-trivial. We ended up cutting and pasting it in several places
because there was no vprintf-style function for strbufs (which in turn
was held up by a lack of va_copy).
Now that we have a fallback va_copy, we can add strbuf_vaddf, the
strbuf equivalent of vsprintf. And we can clean up the cut and paste
mess.
Signed-off-by: Jeff King <peff@peff.net>
Improved-by: Christian Couder <christian.couder@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
GNU printf, and many others, will print the string "(null)" if a NULL
pointer is passed as the argument to a "%s" format specifier. Some
implementations (like on Solaris) do not detect a NULL pointer and will
produce a segfault in this case.
So, fix this by ensuring that pointer variables do not contain the value
NULL. Assign the string "(null)" to the variables are NULL.
Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* nd/setup: (47 commits)
setup_work_tree: adjust relative $GIT_WORK_TREE after moving cwd
git.txt: correct where --work-tree path is relative to
Revert "Documentation: always respect core.worktree if set"
t0001: test git init when run via an alias
Remove all logic from get_git_work_tree()
setup: rework setup_explicit_git_dir()
setup: clean up setup_discovered_git_dir()
t1020-subdirectory: test alias expansion in a subdirectory
setup: clean up setup_bare_git_dir()
setup: limit get_git_work_tree()'s to explicit setup case only
Use git_config_early() instead of git_config() during repo setup
Add git_config_early()
git-rev-parse.txt: clarify --git-dir
t1510: setup case #31
t1510: setup case #30
t1510: setup case #29
t1510: setup case #28
t1510: setup case #27
t1510: setup case #26
t1510: setup case #25
...
This way, the next caller that wants to disable our memory reclamation
machinery does not have to define its own do_nothing() stub.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This avoids a potential race condition when async procedures are
implemented as threads where release_pack_memory() can be called from
different threads without locking under memory pressure.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that str_buf takes care of all the allocations, there is
no more gain to pass an argument count.
So this patch removes the "count" argument from:
- "sq_quote_argv"
- "trace_argv_printf"
and all the callers.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Using the helper function to test for absolute paths makes porting easier.
Signed-off-by: Steffen Prohaska <prohaska@zib.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Solaris 9's vsnprintf implementation returns -1 if we pass it a
buffer of length 0. The only way to get it to give us the actual
length necessary for the formatted string is to grow the buffer
out to have at least 1 byte available in the strbuf and then ask
it to compute the length.
If the available space is 0 I'm growing it out by 64 to ensure
we will get an accurate length estimate from all implementations.
Some callers may need to grow the strbuf again but 64 should be a
reasonable enough initial growth.
We also no longer silently fail to append to the string when we are
faced with a broken vsnprintf implementation. On Solaris 9 this
silent failure caused me to no longer be able to execute "git clone"
as we tried to exec the empty string rather than "git-clone".
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* sq_quote_buf is made public, and works on a strbuf.
* sq_quote_argv also works on a strbuf.
* make sq_quote_argv take a "maxlen" argument to check the buffer won't grow
too big.
Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* drop nfasprintf.
* move nfvasprintf into imap-send.c back, and let it work on a 8k buffer,
and die() in case of overflow. It should be enough for imap commands, if
someone cares about imap-send, he's welcomed to fix it properly.
* replace nfvasprintf use in merge-recursive with a copy of the strbuf_addf
logic, it's one place, we'll live with it.
To ease the change, output_buffer string list is replaced with a strbuf ;)
* rework trace.c to call vsnprintf itself. It's used to format strerror()s
and git command names, it should never be more than a few octets long, let
it work on a 8k static buffer with vsnprintf or die loudly.
Signed-off-by: Pierre Habouzit <madcoder@debian.org>
In order to track and build on top of a branch 'topic' you track from
your upstream repository, you often would end up doing this sequence:
git checkout -b mytopic origin/topic
git config --add branch.mytopic.remote origin
git config --add branch.mytopic.merge refs/heads/topic
This would first fork your own 'mytopic' branch from the 'topic'
branch you track from the 'origin' repository; then it would set up two
configuration variables so that 'git pull' without parameters does the
right thing while you are on your own 'mytopic' branch.
This commit adds a --track option to git-branch, so that "git
branch --track mytopic origin/topic" performs the latter two actions
when creating your 'mytopic' branch.
If the configuration variable branch.autosetupmerge is set to true, you
do not have to pass the --track option explicitly; further patches in
this series allow setting the variable with a "git remote add" option.
The configuration variable is off by default, and there is a --no-track
option to countermand it even if the variable is set.
Signed-off-by: Paolo Bonzini <bonzini@gnu.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We recently introduced a write_in_full() which would either write
the specified object or emit an error message and fail. In order
to fix the read side we now want to introduce a read_in_full()
but without an error emit. This patch cleans up the naming
of this family of calls:
1) convert the existing write_or_whine() to write_or_whine_pipe()
to better indicate its pipe specific nature,
2) convert the existing write_in_full() calls to write_or_whine()
to better indicate its nature,
3) introduce a write_in_full() providing a write or fail semantic,
and
4) convert write_or_whine() and write_or_whine_pipe() to use
write_in_full().
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
If GIT_TRACE is set to an absolute path (starting with a
'/' character), we interpret this as a file path and we
trace into it.
Also if GIT_TRACE is set to an integer value greater than
1 and lower than 10, we interpret this as an open fd value
and we trace into it.
Note that this behavior is not compatible with the
previous one.
We also trace whole messages using one write(2) call to
make sure messages from processes do net get mixed up in
the middle.
This patch makes it possible to get trace information when
running "make test".
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Nguyễn Thái Ngọc Duy
Jeff King
Junio C Hamano
Stephen Boyd
Brandon Casey
Vasyl' Vavrychuk
Johannes Sixt
Allan Caffee
Christian Couder
Steffen Prohaska
Shawn O. Pearce
Pierre Habouzit
Paolo Bonzini
Andy Whitcroft