The rules used by "git push" and "git fetch" to determine if a ref
can or cannot be updated were inconsistent; specifically, fetching
to update existing tags were allowed even though tags are supposed
to be unmoving anchoring points. "git fetch" was taught to forbid
updates to existing tags without the "--force" option.
* ab/fetch-tags-noclobber:
fetch: stop clobbering existing tags without --force
fetch: document local ref updates with/without --force
push doc: correct lies about how push refspecs work
push doc: move mention of "tag <tag>" later in the prose
push doc: remove confusing mention of remote merger
fetch tests: add a test for clobbering tag behavior
push tests: use spaces in interpolated string
push tests: make use of unused $1 in test description
fetch: change "branch" to "reference" in --force -h output
Change "fetch" to treat "+" in refspecs (aka --force) to mean we
should clobber a local tag of the same name.
This changes the long-standing behavior of "fetch" added in
853a3697dc ("[PATCH] Multi-head fetch.", 2005-08-20). Before this
change, all tag fetches effectively had --force enabled. See the
git-fetch-script code in fast_forward_local() with the comment:
> Tags need not be pointing at commits so there is no way to
> guarantee "fast-forward" anyway.
That commit and the rest of the history of "fetch" shows that the
"+" (--force) part of refpecs was only conceived for branch updates,
while tags have accepted any changes from upstream unconditionally and
clobbered the local tag object. Changing this behavior has been
discussed as early as 2011[1].
The current behavior doesn't make sense to me, it easily results in
local tags accidentally being clobbered. We could namespace our tags
per-remote and not locally populate refs/tags/*, but as with my
97716d217c ("fetch: add a --prune-tags option and fetch.pruneTags
config", 2018-02-09) it's easier to work around the current
implementation than to fix the root cause.
So this change implements suggestion #1 from Jeff's 2011 E-Mail[1],
"fetch" now only clobbers the tag if either "+" is provided as part of
the refspec, or if "--force" is provided on the command-line.
This also makes it nicely symmetrical with how "tag" itself works when
creating tags. I.e. we refuse to clobber any existing tags unless
"--force" is supplied. Now we can refuse all such clobbering, whether
it would happen by clobbering a local tag with "tag", or by fetching
it from the remote with "fetch".
Ref updates outside refs/{tags,heads/* are still still not symmetrical
with how "git push" works, as discussed in the recently changed
pull-fetch-param.txt documentation. This change brings the two
divergent behaviors more into line with one another. I don't think
there's any reason "fetch" couldn't fully converge with the behavior
used by "push", but that's a topic for another change.
One of the tests added in 31b808a032 ("clone --single: limit the fetch
refspec to fetched branch", 2012-09-20) is being changed to use
--force where a clone would clobber a tag. This changes nothing about
the existing behavior of the test.
1. https://public-inbox.org/git/20111123221658.GA22313@sigill.intra.peff.net/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change various tests that use an idiom of the form:
>expect &&
test_cmp expect actual
To instead use:
test_must_be_empty actual
The test_must_be_empty() wrapper was introduced in ca8d148daf ("test:
test_must_be_empty helper", 2013-06-09). Many of these tests have been
added after that time. This was mostly found with, and manually pruned
from:
git grep '^\s+>.*expect.* &&$' t
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a --no-tags option to clone without fetching any tags.
Without this change there's no easy way to clone a repository without
also fetching its tags.
When supplying --single-branch the primary remote branch will be
cloned, but in addition tags will be followed & retrieved. Now
--no-tags can be added --single-branch to clone a repository without
tags, and which only tracks a single upstream branch.
This option works without --single-branch as well, and will do a
normal clone but not fetch any tags.
Many git commands pay some fixed overhead as a function of the number
of references. E.g. creating ~40k tags in linux.git will cause a
command like `git log -1 >/dev/null` to run in over a second instead
of in a matter of milliseconds, in addition numerous other things will
slow down, e.g. "git log <TAB>" with the bash completion will slowly
show ~40k references instead of 1.
The user might want to avoid all of that overhead to simply use a
repository like that to browse the "master" branch, or something like
a CI tool might want to keep that one branch up-to-date without caring
about any other references.
Without this change the only way of accomplishing this was either by
manually tweaking the config in a fresh repository:
git init git &&
cat >git/.git/config <<EOF &&
[remote "origin"]
url = git@github.com:git/git.git
tagOpt = --no-tags
fetch = +refs/heads/master:refs/remotes/origin/master
[branch "master"]
remote = origin
merge = refs/heads/master
EOF
cd git &&
git pull
Which requires hardcoding the "master" name, which may not be the main
--single-branch would have retrieved, or alternatively by setting
tagOpt=--no-tags right after cloning & deleting any existing tags:
git clone --single-branch git@github.com:git/git.git &&
cd git &&
git config remote.origin.tagOpt --no-tags &&
git tag -l | xargs git tag -d
Which of course was also subtly buggy if --branch was pointed at a
tag, leaving the user in a detached head:
git clone --single-branch --branch v2.12.0 git@github.com:git/git.git &&
cd git &&
git config remote.origin.tagOpt --no-tags &&
git tag -l | xargs git tag -d
Now all this complexity becomes the much simpler:
git clone --single-branch --no-tags git@github.com:git/git.git
Or in the case of cloning a single tag "branch":
git clone --single-branch --branch v2.12.0 --no-tags git@github.com:git/git.git
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change occurrences "cd" followed by "fetch" on a single line to be on
two lines.
This is purely a stylistic change pointed out in code review for an
unrelated patch. Change the these tests use so new tests added later
using the more common style don't look out of place.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When trying to find a good spot for testing clone with submodules, I
got confused where to add a new test file. There are both tests in t560*
as well as t57* both testing the clone command. t/README claims the
second digit is to indicate the command, which is inconsistent to the
current naming structure.
Rename all t57* tests to be in t56* to follow the pattern of the digits
as laid out in t/README.
It would have been less work to rename t56* => t57* because there are less
files, but the tests in t56* look more basic and I assumed the higher the
last digits the more complicated niche details are tested, so with the patch
now it looks more in order to me.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
