[v2] describe-doc: clarify default length of abbreviation

Commit Message

Anders Höckersten May 17, 2021, 5:53 a.m. UTC

From: =?UTF-8?q?Anders=20H=C3=B6ckersten?= <[e-mail]>

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 <[e-mail]>
---
    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.
    
    Changes since v1:
    
     * tweaked the wording in --abbrev parameter to better match
       implementation, as suggested by Bagas Sanjaya
     * trailing whitespace removed
    
    Signed-off-by: Anders Höckersten [e-mail]

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1026%2Fahockersten%2Fdescribe-doc-abbreviation-clarification-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1026/ahockersten/describe-doc-abbreviation-clarification-v2
Pull-Request: https://github.com/git/git/pull/1026

Range-diff vs v1:

 1:  a3aa09ab6fca ! 1:  4cf527801901 describe-doc: clarify default length of abbreviation
     @@ Documentation/git-describe.txt: OPTIONS
      -	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.
     ++	will vary according to the number of objects in 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
      @@ Documentation/git-describe.txt: at the end.
       
       The number of additional commits is the number
     @@ Documentation/git-describe.txt: at the end.
      -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 
     ++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


 Documentation/git-describe.txt | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)


base-commit: 48bf2fa8bad054d66bd79c6ba903c89c704201f7

Comments

Derrick Stolee May 17, 2021, 4:44 p.m. UTC | #1

On 5/17/2021 1:53 AM, Anders Höckersten via GitGitGadget wrote:
> From: =?UTF-8?q?Anders=20H=C3=B6ckersten?= <[e-mail]>
> 
> 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.

I'm a bit late to the party, but am interested in our abbreviation
code. I found these updates to be sensible, and that you appropriately
adjusted from v1 according to the feedback.

Thanks,
-Stolee

Patch

diff --git a/Documentation/git-describe.txt b/Documentation/git-describe.txt
index a88f6ae2c6e7..c6a79c2a0f29 100644
--- a/Documentation/git-describe.txt
+++ b/Documentation/git-describe.txt
@@ -63,9 +63,10 @@  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
+	Instead of using the default number of hexadecimal digits (which
+	will vary according to the number of objects in 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>::
@@ -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.