From: Yukai Chou <muzimuzhi@gmail.com>
Date: Thu, 29 Aug 2024 23:16:27 GMT
Subject: Re: Tags auto fetched by "git fetch origin" but not "git fetch origin main"
Message-ID: <CAEg0tHSP60oU8a2tSfTqCOiz2AOfvR46ChWPJDMF_dTVofGymg@mail.gmail.com>
In-Reply-To: <ZtDo--AY43-bPTHG@tapette.crustytoothpaste.net>

brian m. carlson <sandals@crustytoothpaste.net> 于2024年8月30日周五 05:32写道：
>
> On 2024-08-28 at 23:23:57, Yukai Chou wrote:
> > In using `git fetch [<options>] [<repository> [<refspec>…]]`,
> > - when a branch is specified as <refspec>, no tags are fetched automatically;
> > - when no <refspec>s are specified, tags are fetched automatically.
>
> Yes, this is expected.  Tags are refs, and when you specify no refspec,
> you're asking for the default behaviour, which usually involves fetching
> tags.

According to the doc section CONFIGURED REMOTE-TRACKING BRANCHES [1],
when no refspec is specified,

  remote.<repository>.fetch values are used as the refspecs

Then according to doc of <refspec> [2],

  Since Git version 2.20, fetching to update refs/tags/* works the same
  way as when pushing. I.e. any updates will be rejected without + in
  the refspec (or --force).

So the tags are fetched due to the + in the remote.<repository>.fetch
values, are they?

> For example, if I say, `git fetch origin
> refs/heads/main:refs/heads/main`, it would be very unexpected for it to
> fetch tags as well; ... .

Actually,

  git fetch --update-head-ok origin refs/heads/main:refs/heads/main

does fetch tags "that points into the histories being fetched".

This time the refspec is given on the command line, without +.

According to the doc of CONFIGURED REMOTE-TRACKING BRANCHES [1],

  When used in this way, the remote.<repository>.fetch values do not
  have any effect in deciding what gets fetched (i.e. the values are
  not used as refspecs when the command-line lists refspecs); they
  are only used to decide where the refs that are fetched are stored
  by acting as a mapping.

[1] https://git-scm.com/docs/git-fetch#_configured_remote_tracking_branches
[2] https://git-scm.com/docs/git-fetch#Documentation/git-fetch.txt-ltrefspecgt

Yukai