Subject: Re: [PATCH] describe-doc: clarify default length of abbreviation

From: Junio C Hamano <[email-masked]>
Date: Sun, 16 May 2021 20:34:37 +0900

"Anders Höckersten via GitGitGadget"  <[email-masked]>
writes:

> From: =?UTF-8?q?Anders=20H=C3=B6ckersten?= <[email-masked]>
>
> Clarify the default length used for the abbreviated form used for
> commits in git describe.
>
> The behavior was modified in Git 2.11.0, but the documentation was not
> updated to clarify the new behavior.
>
> Signed-off-by: Anders Höckersten <[email-masked]>
> ---
>     describe-doc: clarify default length of abbreviation
>     
>     Clarify the default length used for the abbreviated form used for
>     commits in git describe.
>     
>     The behavior was modified in Git 2.11.0, but the documentation was not
>     updated to clarify the new behavior.
>     
>     Signed-off-by: Anders Höckersten [email-masked]
>
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1026%2Fahockersten%2Fdescribe-doc-abbreviation-clarification-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1026/ahockersten/describe-doc-abbreviation-clarification-v1
> Pull-Request: https://github.com/git/git/pull/1026

.git/rebase-apply/patch:32: trailing whitespace.
	will vary according to the size of the repository with a default of 
.git/rebase-apply/patch:34: trailing whitespace.
	as needed to form a unique object name.  An <n> of 0 will suppress 
.git/rebase-apply/patch:46: trailing whitespace.
of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`). The 
.git/rebase-apply/patch:47: trailing whitespace.
length of the abbreviation scales as the repository grows, using the 
.git/rebase-apply/patch:48: trailing whitespace.
approximate number of objects in the repository and a bit of math 
warning: 5 lines applied after fixing whitespace errors.
Applying: describe-doc: clarify default length of abbreviation

Will fix them up while applying, but please be careful the next
time.  A good way to double check is to do

    $ git format-patch -o my.patch origin..
    $ git checkout --detach origin
    $ git am --whitespace=warn my.patch

that is, (1) create a patch series out of the branch you have worked
on, designed to be applied on top of the origin, (2) detach HEAD at
the origin, and (3) apply the patch.  Once you are done, you can go
back to the original branch with

    $ git checkout -

The patch text looks good.

Thanks.

>  Documentation/git-describe.txt | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/git-describe.txt b/Documentation/git-describe.txt
> index a88f6ae2c6e7..f3f41cfac496 100644
> --- a/Documentation/git-describe.txt
> +++ b/Documentation/git-describe.txt
> @@ -63,10 +63,11 @@ OPTIONS
>  	Automatically implies --tags.
>  
>  --abbrev=<n>::
> -	Instead of using the default 7 hexadecimal digits as the
> -	abbreviated object name, use <n> digits, or as many digits
> -	as needed to form a unique object name.  An <n> of 0
> -	will suppress long format, only showing the closest tag.
> +	Instead of using the default number of hexadecimal digits (which
> +	will vary according to the size of the repository with a default of 
> +	7) of the abbreviated object name, use <n> digits, or as many digits
> +	as needed to form a unique object name.  An <n> of 0 will suppress 
> +	long format, only showing the closest tag.
>  
>  --candidates=<n>::
>  	Instead of considering only the 10 most recent tags as
> @@ -139,8 +140,11 @@ at the end.
>  
>  The number of additional commits is the number
>  of commits which would be displayed by "git log v1.0.4..parent".
> -The hash suffix is "-g" + unambiguous abbreviation for the tip commit
> -of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
> +The hash suffix is "-g" + an unambigous abbreviation for the tip commit
> +of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`). The 
> +length of the abbreviation scales as the repository grows, using the 
> +approximate number of objects in the repository and a bit of math 
> +around the birthday paradox, and defaults to a minimum of 7.
>  The "g" prefix stands for "git" and is used to allow describing the version of
>  a software depending on the SCM the software is managed with. This is useful
>  in an environment where people may use different SCMs.
>
> base-commit: 48bf2fa8bad054d66bd79c6ba903c89c704201f7