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Diffstat (limited to 'Documentation/git-fetch.txt')
| -rw-r--r-- | Documentation/git-fetch.txt | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/Documentation/git-fetch.txt b/Documentation/git-fetch.txt index b153aefa68..e319935597 100644 --- a/Documentation/git-fetch.txt +++ b/Documentation/git-fetch.txt @@ -99,6 +99,93 @@ The latter use of the `remote.<repository>.fetch` values can be overridden by giving the `--refmap=<refspec>` parameter(s) on the command line. +PRUNING +------- + +Git has a default disposition of keeping data unless it's explicitly +thrown away; this extends to holding onto local references to branches +on remotes that have themselves deleted those branches. + +If left to accumulate, these stale references might make performance +worse on big and busy repos that have a lot of branch churn, and +e.g. make the output of commands like `git branch -a --contains +<commit>` needlessly verbose, as well as impacting anything else +that'll work with the complete set of known references. + +These remote-tracking references can be deleted as a one-off with +either of: + +------------------------------------------------ +# While fetching +$ git fetch --prune <name> + +# Only prune, don't fetch +$ git remote prune <name> +------------------------------------------------ + +To prune references as part of your normal workflow without needing to +remember to run that, set `fetch.prune` globally, or +`remote.<name>.prune` per-remote in the config. See +linkgit:git-config[1]. + +Here's where things get tricky and more specific. The pruning feature +doesn't actually care about branches, instead it'll prune local <-> +remote-references as a function of the refspec of the remote (see +`<refspec>` and <<CRTB,CONFIGURED REMOTE-TRACKING BRANCHES>> above). + +Therefore if the refspec for the remote includes +e.g. `refs/tags/*:refs/tags/*`, or you manually run e.g. `git fetch +--prune <name> "refs/tags/*:refs/tags/*"` it won't be stale remote +tracking branches that are deleted, but any local tag that doesn't +exist on the remote. + +This might not be what you expect, i.e. you want to prune remote +`<name>`, but also explicitly fetch tags from it, so when you fetch +from it you delete all your local tags, most of which may not have +come from the `<name>` remote in the first place. + +So be careful when using this with a refspec like +`refs/tags/*:refs/tags/*`, or any other refspec which might map +references from multiple remotes to the same local namespace. + +Since keeping up-to-date with both branches and tags on the remote is +a common use-case the `--prune-tags` option can be supplied along with +`--prune` to prune local tags that don't exist on the remote, and +force-update those tags that differ. Tag pruning can also be enabled +with `fetch.pruneTags` or `remote.<name>.pruneTags` in the config. See +linkgit:git-config[1]. + +The `--prune-tags` option is equivalent to having +`refs/tags/*:refs/tags/*` declared in the refspecs of the remote. This +can lead to some seemingly strange interactions: + +------------------------------------------------ +# These both fetch tags +$ git fetch --no-tags origin 'refs/tags/*:refs/tags/*' +$ git fetch --no-tags --prune-tags origin +------------------------------------------------ + +The reason it doesn't error out when provided without `--prune` or its +config versions is for flexibility of the configured versions, and to +maintain a 1=1 mapping between what the command line flags do, and +what the configuration versions do. + +It's reasonable to e.g. configure `fetch.pruneTags=true` in +`~/.gitconfig` to have tags pruned whenever `git fetch --prune` is +run, without making every invocation of `git fetch` without `--prune` +an error. + +Pruning tags with `--prune-tags` also works when fetching a URL +instead of a named remote. These will all prune tags not found on +origin: + +------------------------------------------------ +$ git fetch origin --prune --prune-tags +$ git fetch origin --prune 'refs/tags/*:refs/tags/*' +$ git fetch <url of origin> --prune --prune-tags +$ git fetch <url of origin> --prune 'refs/tags/*:refs/tags/*' +------------------------------------------------ + OUTPUT ------ |