Subject: Re: [PATCH v2] gitk: Add a "Copy commit summary" command

From: Junio C Hamano <[email-masked]>
Date: Thu, 16 Jul 2015 10:02:41 -0700

Beat Bolli <[email-masked]> writes:

> When referring to earlier commits in commit messages or other text, one
> of the established formats is
>
>     <abbrev-sha> ("<summary>", <author-date>)
> ...
> +proc copysummary {} {
> +    global rowmenuid commitinfo
> +
> +    set id [string range $rowmenuid 0 7]
> +    set info $commitinfo($rowmenuid)
> +    set commit [lindex $info 0]

7 hexdigits is not always an appropriate value for all projects.
The minimum necessary to guarantee uniqueness varies on project, and
it is not a good idea to hardcode such a small value.  Not-so-old
Linux kernel history seems to use at least 12, for example.

I believe that the "one of the established formats" comes from a
"git one" alias I published somewhere long time ago, that did
something like this:

  git show -s --abbrev=8 --pretty='format:%h (%s, %ai' "$@" |
  sed -e 's/ [012][0-9]:[0-5][0-9]:[0-5][0-9] [-+][0-9][0-9][0-9][0-9]$/)/'

where the combination of --abbrev=8 and format:%h asks for a unique
abbreviation that is at least 8 hexdigits long but can use more than
8 if it is not long enough to uniquely identify the given commit.

I do not offhand know how $commitinfo is populated, but perhaps you
can tweak that code to ask for both %H (for the full commit object
ID) and %h (for the unique abbreviation of appropriate length) and
store the value for %h to a new field in the $commitinfo($rowmenuid)
array, so that you do not have to have such a hard-coded truncation
here?

> +    set date [formatdate [lindex $info 2]]
> +    set summary "$id (\"$commit\", $date)"
> +
> +    clipboard clear
> +    clipboard append $summary
> +}
> +
>  proc writecommit {} {
>      global rowmenuid wrcomtop commitinfo wrcomcmd NS