Re: [PATCH 2/2 v4] tag: support configuring --sort via .gitconfig

> Jacob Keller <jacob.e.keller@intel.com> writes:
> 
> > Add support for configuring default sort ordering for git tags. Command
> > line option will override this configured value, using the exact same
> > syntax.
> >
> > Cc: Jeff King <peff@peff.net>
> > Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> > ---
> > - v4
> > * base on top of suggested change by Jeff King to use skip_prefix instead
> >
> >  Documentation/config.txt  |  6 ++++++
> >  Documentation/git-tag.txt |  1 +
> >  builtin/tag.c             | 46 ++++++++++++++++++++++++++++++++--------------
> >  t/t7004-tag.sh            | 21 +++++++++++++++++++++
> >  4 files changed, 60 insertions(+), 14 deletions(-)
> >
> > diff --git a/Documentation/config.txt b/Documentation/config.txt
> > index 1d718bdb9662..ad8e75fed988 100644
> > --- a/Documentation/config.txt
> > +++ b/Documentation/config.txt
> > @@ -2354,6 +2354,12 @@ submodule.<name>.ignore::
> >  	"--ignore-submodules" option. The 'git submodule' commands are not
> >  	affected by this setting.
> >  
> > +tag.sort::
> > +	This variable is used to control the sort ordering of tags. It is
> > +	interpreted precisely the same way as "--sort=<value>". If --sort is
> > +	given on the command line it will override the selection chosen in the
> > +	configuration. See linkgit:git-tag[1] for more details.
> > +
> 
> This is not technically incorrect per-se, but the third sentence
> talks about "--sort" on "the command line" while this applies only
> to "the command line of the 'git tag' command" and nobody else's
> "--sort" option.
> 
> Perhaps rephrasing it like this may be easier to understand?
> 
> 	When "git tag" command is used to list existing tags,
>         without "--sort=<value>" option on the command line,
> 	the value of this variable is used as the default.
> 
> This way, it would be clear, without explicitly saying anything,
> that the value will be spelled exactly the same way as you would
> spell the value for the --sort option on the command line.
> 
> > diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
> > index b424a1bc48bb..2d246725aeb5 100644
> > --- a/Documentation/git-tag.txt
> > +++ b/Documentation/git-tag.txt
> > @@ -317,6 +317,7 @@ include::date-formats.txt[]
> >  SEE ALSO
> >  --------
> >  linkgit:git-check-ref-format[1].
> > +linkgit:git-config[1].
> 
> It is not particularly friendly to readers to refer to
> "git-config[1]" from any other page, if done without spelling out
> which variable the reader is expected to look up.  Some addition
> to the description of the "--sort" option is needed if this SEE ALSO
> were to be any useful, I guess?
> 
> 	--sort=<type>::
>                 ... (existing description) ...
>                 When this option is not given, the sort order
>                 defaults to the value configured for the `tag.sort`
>                 variable, if exists, or lexicographic otherwise.
> 
> or something like that, perhaps?
> 
> > diff --git a/builtin/tag.c b/builtin/tag.c
> > index 7ccb6f3c581b..a53e27d4e7e4 100644
> > --- a/builtin/tag.c
> > +++ b/builtin/tag.c
> > @@ -18,6 +18,8 @@
> >  #include "sha1-array.h"
> >  #include "column.h"
> >  
> > +static int tag_sort = 0;
> 
> Please do not initialize variables in bss segment to 0 by hand.
> 
> If this variable is meant to take one of these *CMP_SORT values
> defined as macro later in this file, it is better to define this
> variable somewhere after and close to the definitions of the macros.
> Perhaps immediately after the "struct tag_filter" is declared?
> 
> > @@ -346,9 +348,33 @@ static const char tag_template_nocleanup[] =
> >  	"Lines starting with '%c' will be kept; you may remove them"
> >  	" yourself if you want to.\n");
> >  
> > +static int parse_sort_string(const char *arg)
> > +{
> > +	int sort = 0;
> > +	int flags = 0;
> > +
> > +	if (skip_prefix(arg, "-", &arg))
> > +		flags |= REVERSE_SORT;
> > +
> > +	if (skip_prefix(arg, "version:", &arg) || skip_prefix(arg, "v:", &arg))
> > +		sort = VERCMP_SORT;
> > +
> > +	if (strcmp(arg, "refname"))
> > +		die(_("unsupported sort specification %s"), arg);
> 
> Hmm.  I _thought_ we try to catch unsupported option value coming
> from the command line and die but at the same time we try *not* to
> die but warn and whatever is sensible when the value comes from the
> configuration, so that .git/config or $HOME/.gitconfig can be shared
> by those who use different versions of Git.
> 
> Do we already have many precedences where we see configuration value
> that our version of Git do not yet understand?
> 
> Not a very strong objection; just something that worries me.
> 
> > +	sort |= flags;
> > +
> > +	return sort;
> > +}
> > +
> >  static int git_tag_config(const char *var, const char *value, void *cb)
> >  {
> > -	int status = git_gpg_config(var, value, cb);
> > +	int status;
> > +
> > +	if (!strcmp(var, "tag.sort")) {
> > +		tag_sort = parse_sort_string(value);
> > +	}
> > +
> 
> Why doesn't this return success after noticing that the variable is
> to be interpreted by this block and nobody else?
> 
> When there is no reason to have things in a particular order, it is
> customary to add new things at the end, not in the front, unless the
> new thing is so much more important than everything else---but then
> we are no longer talking about the case where there is no reason to
> have things in a particular order ;-).
> 
> Remainder of the changes to builtin/tag.c looks good.
> 
> > diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
> > index e4ab0f5b6419..1e8300f6ed7c 100755
> > --- a/t/t7004-tag.sh
> > +++ b/t/t7004-tag.sh
> > @@ -1423,6 +1423,27 @@ EOF
> >  	test_cmp expect actual
> >  '
> >  
> > +test_expect_success 'configured lexical sort' '
> > +	git config tag.sort "v:refname" &&
> > +	git tag -l "foo*" >actual &&
> > +	cat >expect <<EOF &&
> > +foo1.3
> > +foo1.6
> > +foo1.10
> > +EOF
> > +	test_cmp expect actual
> > +'
> 
> Please write the above like so:
> 
> 	...
> 	cat >expect <<-\EOF &&
>         foo1.3
>         ...
>         EOF
>         test_cmp expect actual
> 
> The dash immediately after the here-doc redirection lets us indent
> the data with HT to allow the test boundaries easier to spot, and by
> quoting the token to end here-doc, we relieve the readers from
> having to wonder if there are variable substitutions going on that
> they need to be careful about.

> 
> Overall, I think this is done well.  Thanks for working on it.
> --
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