Does "git fetch --tags" include "git fetch"?
Solution 1
Note: starting with git 1.9/2.0 (Q1 2014), git fetch --tags
fetches tags in addition to what are fetched by the same command line without the option.
To fetch only tags:
git fetch <remote> 'refs/tags/*:refs/tags/*'
In details:
See commit c5a84e9 by Michael Haggerty (mhagger):
Previously, fetch's "
--tags
" option was considered equivalent to specifying the refspecrefs/tags/*:refs/tags/*
on the command line; in particular, it caused the
remote.<name>.refspec
configuration to be ignored.But it is not very useful to fetch tags without also fetching other references, whereas it is quite useful to be able to fetch tags in addition to other references.
So change the semantics of this option to do the latter.If a user wants to fetch only tags, then it is still possible to specifying an explicit refspec:
git fetch <remote> 'refs/tags/*:refs/tags/*'
Please note that the documentation prior to 1.8.0.3 was ambiguous about this aspect of "
fetch --tags
" behavior.
Commit f0cb2f1 (2012-12-14)fetch --tags
made the documentation match the old behavior.
This commit changes the documentation to match the new behavior (seeDocumentation/fetch-options.txt
).
Request that all tags be fetched from the remote in addition to whatever else is being fetched.
Since Git 2.5 (Q2 2015) git pull --tags
is more robust:
See commit 19d122b by Paul Tan (pyokagan
), 13 May 2015.
(Merged by Junio C Hamano -- gitster
-- in commit cc77b99, 22 May 2015)
pull
: remove--tags
error in no merge candidates case
Since 441ed41 ("
git pull --tags
": error out with a better message., 2007-12-28, Git 1.5.4+),git pull --tags
would print a different error message ifgit-fetch
did not return any merge candidates:It doesn't make sense to pull all tags; you probably meant: git fetch --tags
This is because at that time,
git-fetch --tags
would override any configured refspecs, and thus there would be no merge candidates. The error message was thus introduced to prevent confusion.However, since c5a84e9 (
fetch --tags
: fetch tags in addition to other stuff, 2013-10-30, Git 1.9.0+),git fetch --tags
would fetch tags in addition to any configured refspecs.
Hence, if any no merge candidates situation occurs, it is not because--tags
was set. As such, this special error message is now irrelevant.To prevent confusion, remove this error message.
With Git 2.11+ (Q4 2016) git fetch
is quicker.
See commit 5827a03 (13 Oct 2016) by Jeff King (peff
).
(Merged by Junio C Hamano -- gitster
-- in commit 9fcd144, 26 Oct 2016)
fetch
: use "quick"has_sha1_file
for tag following
When fetching from a remote that has many tags that are irrelevant to branches we are following, we used to waste way too many cycles when checking if the object pointed at by a tag (that we are not going to fetch!) exists in our repository too carefully.
This patch teaches fetch to use HAS_SHA1_QUICK to sacrifice accuracy for speed, in cases where we might be racy with a simultaneous repack.
Here are results from the included perf script, which sets up a situation similar to the one described above:
Test HEAD^ HEAD ---------------------------------------------------------- 5550.4: fetch 11.21(10.42+0.78) 0.08(0.04+0.02) -99.3%
That applies only for a situation where:
- You have a lot of packs on the client side to make
reprepare_packed_git()
expensive (the most expensive part is finding duplicates in an unsorted list, which is currently quadratic).- You need a large number of tag refs on the server side that are candidates for auto-following (i.e., that the client doesn't have). Each one triggers a re-read of the pack directory.
- Under normal circumstances, the client would auto-follow those tags and after one large fetch, (2) would no longer be true.
But if those tags point to history which is disconnected from what the client otherwise fetches, then it will never auto-follow, and those candidates will impact it on every fetch.
Git 2.21 (Feb. 2019) seems to have introduced a regression when the config remote.origin.fetch
is not the default one ('+refs/heads/*:refs/remotes/origin/*'
)
fatal: multiple updates for ref 'refs/tags/v1.0.0' not allowed
Git 2.24 (Q4 2019) adds another optimization.
See commit b7e2d8b (15 Sep 2019) by Masaya Suzuki (draftcode
).
(Merged by Junio C Hamano -- gitster
-- in commit 1d8b0df, 07 Oct 2019)
fetch
: useoidset
to keep the want OIDs for faster lookup
During
git fetch
, the client checks if the advertised tags' OIDs are already in the fetch request's want OID set.
This check is done in a linear scan.
For a repository that has a lot of refs, repeating this scan takes 15+ minutes.In order to speed this up, create a
oid_set
for other refs' OIDs.
Solution 2
Note: this answer is only valid for git v1.8 and older.
Most of this has been said in the other answers and comments, but here's a concise explanation:
-
git fetch
fetches all branch heads (or all specified by the remote.fetch config option), all commits necessary for them, and all tags which are reachable from these branches. In most cases, all tags are reachable in this way. -
git fetch --tags
fetches all tags, all commits necessary for them. It will not update branch heads, even if they are reachable from the tags which were fetched.
Summary: If you really want to be totally up to date, using only fetch, you must do both.
It's also not "twice as slow" unless you mean in terms of typing on the command-line, in which case aliases solve your problem. There is essentially no overhead in making the two requests, since they are asking for different information.
Solution 3
I'm going to answer this myself.
I've determined that there is a difference. "git fetch --tags" might bring in all the tags, but it doesn't bring in any new commits!
Turns out one has to do this to be totally "up to date", i.e. replicated a "git pull" without the merge:
$ git fetch --tags
$ git fetch
This is a shame, because it's twice as slow. If only "git fetch" had an option to do what it normally does and bring in all the tags.
Solution 4
The general problem here is that git fetch
will fetch +refs/heads/*:refs/remotes/$remote/*
. If any of these commits have tags, those tags will also be fetched. However if there are tags not reachable by any branch on the remote, they will not be fetched.
The --tags
option switches the refspec to +refs/tags/*:refs/tags/*
. You could ask git fetch
to grab both. I'm pretty sure to just do a git fetch && git fetch -t
you'd use the following command:
git fetch origin "+refs/heads/*:refs/remotes/origin/*" "+refs/tags/*:refs/tags/*"
And if you wanted to make this the default for this repo, you can add a second refspec to the default fetch:
git config --local --add remote.origin.fetch "+refs/tags/*:refs/tags/*"
This will add a second fetch =
line in the .git/config
for this remote.
I spent a while looking for the way to handle this for a project. This is what I came up with.
git fetch -fup origin "+refs/*:refs/*"
In my case I wanted these features
- Grab all heads and tags from the remote so use refspec
refs/*:refs/*
- Overwrite local branches and tags with non-fast-forward
+
before the refspec - Overwrite currently checked out branch if needed
-u
- Delete branches and tags not present in remote
-p
- And force to be sure
-f
Solution 5
In most situations, git fetch
should do what you want, which is 'get anything new from the remote repository and put it in your local copy without merging to your local branches'. git fetch --tags
does exactly that, except that it doesn't get anything except new tags.
In that sense, git fetch --tags
is in no way a superset of git fetch
. It is in fact exactly the opposite.
git pull
, of course, is nothing but a wrapper for a git fetch <thisrefspec>; git merge
. It's recommended that you get used to doing manual git fetch
ing and git merge
ing before you make the jump to git pull
simply because it helps you understand what git pull
is doing in the first place.
That being said, the relationship is exactly the same as with git fetch
. git pull
is the superset of git pull --tags
.
Related videos on Youtube
davidA
Updated on October 06, 2021Comments
-
davidA over 2 years
A nice and simple question - is the function of "git fetch" a strict sub-set of
git fetch --tags
?I.e. if I run
git fetch --tags
, is there ever a reason to immediately rungit fetch
straight afterward?What about
git pull
andgit pull --tags
? Same situation?-
VonC over 10 yearsStarting Git 1..9/2.0 (Q1 2014), the answer will be yes. See my answer below
-
davidA almost 6 yearsTo the editor who "corrected my text" with an edit - one does not necessarily capitalise after a hyphen or an acronym, so your edit was grammatically incorrect, which is why I rejected it.
-
-
VonC over 14 yearsInteresting, I did not experienced that (probably because my repo was up to date at the time of my test.) +1
-
VonC over 14 yearsHow about a '
git remote update myRemoteRepo
': would that fetch remote content and tags? -
CB Bailey over 14 yearsgit fetch --tags will bring in all commits needed to support tags on the remote repository, but it doesn't fetch commits on branches that aren't included in the set of tags on the remote repository.
-
Tim Visher over 14 yearsI do
git fetch
all the time and it consistently pulls down any new commits and any new tags. What version of Git are you running? -
davidA over 14 yearsThat's not quite what I said - I said that "git fetch --tags" does not pull down new commits. It is not a super-set of "git fetch", which does pull down new commits. So if you want the behaviour of 'git fetch' and the behaviour of 'git fetch --tags', you have to run both of them. I'll look into 'git remote update myRemote'.
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davidA over 14 yearsThanks for your comment. I'm running git in Cygwin over a high-latency network - it's twice as slow when there's nothing to fetch for either (about 5 seconds).
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davidA over 14 years"git pull is the superset of git pull --tags" - but... 'git fetch' is not the superset of 'git fetch --tags' so the relationship isn't exactly the same...?
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davidA over 14 yearsI think the issue is that 'git fetch' only fetches tags on tracked branches. We have a script that allows users to select a working branch, so by default there are many branches that are not currently tracked by an individual.
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davidA over 14 yearsI haven't tried git-remote yet, but it's on my ever-growing to-do list :)
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Cascabel over 14 yearsEdited to reflect the tracked branches only part. My mistake there - another default I don't mess with much.
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davidA over 14 yearsFTR, 'git remote update myRemoteRepo' does not work well - does not seem to do what 'git fetch && git fetch --tags' does, especially as a subsequent merge has no effect.
-
Arc over 13 yearsJust found this question... well, it seems to me that
git pull
does not get all tags but only those reachable from the current branch heads. However,git pull --tags
fetches all tags and is apparently equivalent togit fetch --tags
. -
larsks over 11 yearsNote that
git remote update
is not actually a substitute forgit fetch
andgit fetch --tags
.git remote update
will not update existing tags that have changed, although it will bring in new tags. Onlygit fetch --tags
will update already existing tags. -
gnarf about 11 years@TimVisher
git fetch
won't grab tags that aren't in the commit log of a branch. jQuery UI does this for instance on a release tag. We do agit checkout -b temp-branch
, do our release, add files needed for the release, update version, etc, thengit commit -m "1.10.x" ; git tag 1.10.x; git push --tags
then we delete our local temp branch. There is no remote branch that reaches that tag, andgit fetch
will never download it. -
gnarf about 11 years@Iarsks I removed the suggestion to
remote update
from the answer, I did some testing and proved your claim. Thanks for the comment it saved me thinking I'd found a solution. -
gnarf about 11 yearsThere is actually overhead in grabbing all that information twice, there is handshaking logging in, pack time, etc. You can do this with a single
git fetch
- see my answer. -
Cascabel about 11 years@gnarf Honestly, if tags are changing, the solution is to tell the repository owners to stop overwriting them. The point of tags is to mark fixed points in history.
-
Cascabel about 11 years@gnarf Also, tags should in practice only be on branches, so fetching tags is just fetching refs, with no overhead in packing.
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gnarf about 11 years@Jefromi we do not overwrite tags, but we orphan them. There are files added on every release that we do not want in the branches anywhere. A standard
fetch
does not retrieve them. -
redolent about 10 yearsThis should be the answer.
-
Dmitry Minkovsky about 10 years+1 for "The
--tags
option switches the refspec to+refs/tags/*:refs/tags/*
". Although,man git-fetch
, seems to specify that refspec without the leading+
(refs/tags/*:refs/tags/*
). -
Rana Ghosh over 9 years"and all tags which are reachable from these branches" Can you elaborate on what this means? What can you do to make a tag reachable. What can you do to make it not reachable?
-
Cascabel over 9 years@tieTYT "Reachable" means "in the history of", as in, reachable via the history graph, by going from a commit to its parent, to that commit's parent, and so on.
-
Robert Siemer almost 9 years
remote.origin.fetch
defaults to+refs/heads/*:refs/remotes/origin/*
, i.e. the+
version, isn’t it? (That means, origin/branch will be overwritten, no matter where origin/branch is right now locally.) -
Robert Siemer almost 9 years...and at the time of writing, recent
git --tags
were fetching tags in addition to everything else already. See @VonC ’s answer. -
Christopher almost 9 yearsAnother weird quirk with
git remote update
: it seems to re-download previously fetched tags, but it won't download any new ones. The only way to do that appears to begit fetch --tags
. -
ankostis over 6 yearsThis thread in git-list discusses the possibility to amend the behavior of
git fetch <remote> <branch>
to auto-follow tags (since it already updates remote-trackings AGAINST original intentions): public-inbox.org/git/… -
VonC over 6 years@ankostis Interesting: as Junio mentions in public-inbox.org/git/…, "going back to the old behaviour may be one option to address the issue being discussed in this thread." (but they won't: public-inbox.org/git/…)
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John Fantastico about 5 yearsWould it have been possible for Git to expose more unnecessary complexity to the end-user, requiring syntax-heavy commands to the point of resembling hacks to perform common operations? I don't think enough of the internals are required knowledge yet.
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VonC about 5 years@JohnFantastico I can understand that point of view. I have seen that before: news.ycombinator.com/item?id=16587496. Or hackernoon.com/… ("The Git commands are just a leaky abstraction over the data storage.")
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Vadorequest about 5 years@VonC Using git v2.21, a new behaviour has broken the old behaviour. I don't know the details but basically it breaks
git clone
iffetch = +refs/tags/*:refs/tags/*
is used (in .gitconfig, for instance). Maybe you want to update your answer? I would but I don't know what has changed under the hood so I can't really explain it properly. See apple.stackexchange.com/questions/352404/… -
VonC about 5 years@Vadorequest Thank you. I have updated the answer and will keep a look out to the mailing list: public-inbox.org/git/?q=fetch
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Gabriel Staples about 3 yearsI'd like to emphasize this part of the answer:
git fetch <remote> 'refs/tags/*:refs/tags/*'
to fetch ONLY tags! Super useful. Just what I needed. -
VonC about 3 years@GabrielStaples Good point. I have edited the answer accordingly.