diff options
author | Ævar Arnfjörð Bjarmason <avarab@gmail.com> | 2018-08-31 22:10:02 +0200 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2018-08-31 23:04:06 +0200 |
commit | fe802bd21e81cceedff2db79cc3c9a5ad75b4f93 (patch) | |
tree | 3f41f204edc88ddfa2ca087870cf6d103fa952f9 /Documentation/git-push.txt | |
parent | push doc: move mention of "tag <tag>" later in the prose (diff) | |
download | git-fe802bd21e81cceedff2db79cc3c9a5ad75b4f93.tar.xz git-fe802bd21e81cceedff2db79cc3c9a5ad75b4f93.zip |
push doc: correct lies about how push refspecs work
There's complex rules governing whether a push is allowed to take
place depending on whether we're pushing to refs/heads/*, refs/tags/*
or refs/not-that/*. See is_branch() in refs.c, and the various
assertions in refs/files-backend.c. (e.g. "trying to write non-commit
object %s to branch '%s'").
This documentation has never been quite correct, but went downhill
after dbfeddb12e ("push: require force for refs under refs/tags/",
2012-11-29) when we started claiming that <dst> couldn't be a tag
object, which is incorrect. After some of the logic in that patch was
changed in 256b9d70a4 ("push: fix "refs/tags/ hierarchy cannot be
updated without --force"", 2013-01-16) the docs weren't updated, and
we've had some version of documentation that confused whether <src>
was a tag or not with whether <dst> would accept either an annotated
tag object or the commit it points to.
This makes the intro somewhat more verbose & complex, perhaps we
should have a shorter description here and split the full complexity
into a dedicated section. Very few users will find themselves needing
to e.g. push blobs or trees to refs/custom-namespace/* (or blobs or
trees at all), and that could be covered separately as an advanced
topic.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Documentation/git-push.txt')
-rw-r--r-- | Documentation/git-push.txt | 52 |
1 files changed, 44 insertions, 8 deletions
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt index 71c78ac1a4..f345bd30fc 100644 --- a/Documentation/git-push.txt +++ b/Documentation/git-push.txt @@ -74,14 +74,50 @@ without any `<refspec>` on the command line. Otherwise, missing `:<dst>` means to update the same ref as the `<src>`. + The object referenced by <src> is used to update the <dst> reference -on the remote side. By default this is only allowed if <dst> is not -a tag (annotated or lightweight), and then only if it can fast-forward -<dst>. By having the optional leading `+`, you can tell Git to update -the <dst> ref even if it is not allowed by default (e.g., it is not a -fast-forward.). -+ -Pushing an empty <src> allows you to delete the <dst> ref from -the remote repository. +on the remote side. Whether this is allowed depends on where in +`refs/*` the <dst> reference lives as described in detail below, in +those sections "update" means any modifications except deletes, which +as noted after the next few sections are treated differently. ++ +The `refs/heads/*` namespace will only accept commit objects, and +updates only if they can be fast-forwarded. ++ +The `refs/tags/*` namespace will accept any kind of object (as +commits, trees and blobs can be tagged), and any updates to them will +be rejected. ++ +It's possible to push any type of object to any namespace outside of +`refs/{tags,heads}/*`. In the case of tags and commits, these will be +treated as if they were the commits inside `refs/heads/*` for the +purposes of whether the update is allowed. ++ +I.e. a fast-forward of commits and tags outside `refs/{tags,heads}/*` +is allowed, even in cases where what's being fast-forwarded is not a +commit, but a tag object which happens to point to a new commit which +is a fast-forward of the commit the last tag (or commit) it's +replacing. Replacing a tag with an entirely different tag is also +allowed, if it points to the same commit, as well as pushing a peeled +tag, i.e. pushing the commit that existing tag object points to, or a +new tag object which an existing commit points to. ++ +Tree and blob objects outside of `refs/{tags,heads}/*` will be treated +the same way as if they were inside `refs/tags/*`, any update of them +will be rejected. ++ +All of the rules described above about what's not allowed as an update +can be overridden by adding an the optional leading `+` to a refspec +(or using `--force` command line option). The only exception to this +is that no amount of forcing will make the `refs/heads/*` namespace +accept a non-commit object. Hooks and configuration can also override +or amend these rules, see e.g. `receive.denyNonFastForwards` in +linkgit:git-config[1] and`pre-receive` and `update` in +linkgit:githooks[5]. ++ +Pushing an empty <src> allows you to delete the <dst> ref from the +remote repository. Deletions are always accepted without a leading `+` +in the refspec (or `--force`), except when forbidden by configuration +or hooks. See `receive.denyDeletes` in linkgit:git-config[1] and +`pre-receive` and `update` in linkgit:githooks[5]. + The special refspec `:` (or `+:` to allow non-fast-forward updates) directs Git to push "matching" branches: for every branch that exists on |