Fetching from a shallow-cloned repository used to be forbidden, primarily because the codepaths involved were not carefully vetted and we did not bother supporting such usage. This attempts to allow object transfer out of a shallow-cloned repository in a controlled way (i.e. the receiver become a shallow repository with truncated history). * nd/shallow-clone: (31 commits) t5537: fix incorrect expectation in test case 10 shallow: remove unused code send-pack.c: mark a file-local function static git-clone.txt: remove shallow clone limitations prune: clean .git/shallow after pruning objects clone: use git protocol for cloning shallow repo locally send-pack: support pushing from a shallow clone via http receive-pack: support pushing to a shallow clone via http smart-http: support shallow fetch/clone remote-curl: pass ref SHA-1 to fetch-pack as well send-pack: support pushing to a shallow clone receive-pack: allow pushes that update .git/shallow connected.c: add new variant that runs with --shallow-file add GIT_SHALLOW_FILE to propagate --shallow-file to subprocesses receive/send-pack: support pushing from a shallow clone receive-pack: reorder some code in unpack() fetch: add --update-shallow to accept refs that update .git/shallow upload-pack: make sure deepening preserves shallow roots fetch: support fetching from a shallow repository clone: support remote shallow repository ...
The same steps are done as in when --update-shallow is not given. The only difference is we now add all shallow commits in "ours" and "theirs" to .git/shallow (aka "step 8"). Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Cloning from a shallow repository does not follow the "8 steps for new .git/shallow" because if it does we need to get through step 6 for all refs. That means commit walking down to the bottom. Instead the rule to create .git/shallow is simpler and, more importantly, cheap: if a shallow commit is found in the pack, it's probably used (i.e. reachable from some refs), so we add it. Others are dropped. One may notice this method seems flawed by the word "probably". A shallow commit may not be reachable from any refs at all if it's attached to an object island (a group of objects that are not reachable by any refs). If that object island is not complete, a new fetch request may send more objects to connect it to some ref. At that time, because we incorrectly installed the shallow commit in this island, the user will not see anything after that commit (fsck is still ok). This is not desired. Given that object islands are rare (C Git never sends such islands for security reasons) and do not really harm the repository integrity, a tradeoff is made to surprise the user occasionally but work faster everyday. A new option --strict could be added later that follows exactly the 8 steps. "git prune" can also learn to remove dangling objects _and_ the shallow commits that are attached to them from .git/shallow. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The main purpose is to trace the URL parser called by git_connect() in connect.c The main features of the parser can be listed as this: - parse out host and path for URLs with a scheme (git:// file:// ssh://) - parse host names embedded by [] correctly - extract the port number, if present - separate URLs like "file" (which are local) from URLs like "host:repo" which should use ssh Add the new parameter "--diag-url" to "git fetch-pack", which prints the value for protocol, host and path to stderr and exits. Signed-off-by: Torsten Bögershausen <tboegi@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The definition of "struct ref" in "cache.h", a header file so central to the system, always confused me. This structure is not about the local ref used by sha1-name API to name local objects. It is what refspecs are expanded into, after finding out what refs the other side has, to define what refs are updated after object transfer succeeds to what values. It belongs to "remote.h" together with "struct refspec". While we are at it, also move the types and functions related to the Git transport connection to a new header file connect.h Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order to make sure the cloned repository is good, we run "rev-list
--objects --not --all $new_refs" on the repository. This is expensive
on large repositories. This patch attempts to mitigate the impact in
this special case.
In the "good" clone case, we only have one pack. If all of the
following are met, we can be sure that all objects reachable from the
new refs exist, which is the intention of running "rev-list ...":
- all refs point to an object in the pack
- there are no dangling pointers in any object in the pack
- no objects in the pack point to objects outside the pack
The second and third checks can be done with the help of index-pack as
a slight variation of --strict check (which introduces a new condition
for the shortcut: pack transfer must be used and the number of objects
large enough to call index-pack). The first is checked in
check_everything_connected after we get an "ok" from index-pack.
"index-pack + new checks" is still faster than the current "index-pack
+ rev-list", which is the whole point of this patch. If any of the
conditions fail, we fall back to the good old but expensive "rev-list
..". In that case it's even more expensive because we have to pay for
the new checks in index-pack. But that should only happen when the
other side is either buggy or malicious.
Cloning linux-2.6 over file://
before after
real 3m25.693s 2m53.050s
user 5m2.037s 4m42.396s
sys 0m13.750s 0m16.574s
A more realistic test with ssh:// over wireless
before after
real 11m26.629s 10m4.213s
user 5m43.196s 5m19.444s
sys 0m35.812s 0m37.630s
This shortcut is not applied to shallow clones, partly because shallow
clones should have no more objects than a usual fetch and the cost of
rev-list is acceptable, partly to avoid dealing with corner cases when
grafting is involved.
This shortcut does not apply to unpack-objects code path either
because the number of objects must be small in order to trigger that
code path.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Even though "git fetch" has full infrastructure to parse refspecs to be fetched and match them against the list of refs to come up with the final list of refs to be fetched, the list of refs that are requested to be fetched were internally converted to a plain list of strings at the transport layer and then passed to the underlying fetch-pack driver. Stop this conversion and instead pass around an array of refs. Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove any references that are available from the remote from the sought list (rather than overwriting their names with NUL characters, as previously). Mark matching entries by writing a non-NULL pointer to string_list_item::util during the iteration, then use filter_string_list() later to filter out the entries that have been marked. Document this aspect of fetch_pack() in a comment in the header file. (More documentation is obviously still needed.) Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of juggling <nr_heads,heads> (sometimes called <nr_match,match>), pass around the list of references to be sought in a single string_list variable called "sought". Future commits will make more use of string_list functionality. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>