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[PATCH] doc: clarify that most --abbrev[=<n>] are about minimum length

From
Junio C Hamano <gitster@pobox.com>
Date
Nov 4, 2020, 01:44 UTC
Message-ID
<xmqqblgdq4k0.fsf_-_@gitster.c.googlers.com>
In-Reply-To
<xmqqk0v1q60l.fsf@gitster.c.googlers.com>

Early text written in 2006 explains the "--abbrev=<n>" option to "show only a partial prefix", without saying that the length of the partial prefix is not necessarily the number given to the option to ensure that the output names the object uniquely.

Luckily, the text written for "git describe" in 2011 explains that the output is made to name the object uniquely using at least <n> hexdigits much clearly.

Model the explanation and update documentation for the diff family of commands, "blame", "branch --verbose", "ls-files" and "ls-tree".

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/diff-options.txt   | 3 ++-
 Documentation/git-blame.txt      | 4 +++-
 Documentation/git-branch.txt     | 8 +++++---
 Documentation/git-ls-files.txt   | 5 +++--
 Documentation/git-ls-tree.txt    | 3 ++-
 Documentation/pretty-options.txt | 3 ++-
 6 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 573fb9bb71..d73fdb8567 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -446,7 +446,8 @@ endif::git-format-patch[]
 --abbrev[=<n>]::
 	Instead of showing the full 40-byte hexadecimal object
 	name in diff-raw format output and diff-tree header
-	lines, show only a partial prefix.
+	lines, show <n> hexadecimal digits, or as many digits
+	as needed to form a unique object name.
 	In diff-patch output format, `--full-index` takes higher
 	precedence, i.e. if `--full-index` is specified, full blob
 	names will be shown regardless of `--abbrev`.
diff --git a/Documentation/git-blame.txt b/Documentation/git-blame.txt
index 7e81541996..34b496d485 100644
--- a/Documentation/git-blame.txt
+++ b/Documentation/git-blame.txt
@@ -87,7 +87,9 @@ include::blame-options.txt[]
 
 --abbrev=<n>::
 	Instead of using the default 7+1 hexadecimal digits as the
-	abbreviated object name, use <n>+1 digits. Note that 1 column
+	abbreviated object name, use <m>+1 digits, where <m> is at
+	least <n> but ensures the commit object names are unique.
+	Note that 1 column
 	is used for a caret to mark the boundary commit.
 
 
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index ace4ad3da8..89611c3959 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -9,7 +9,7 @@ SYNOPSIS
 --------
 [verse]
 'git branch' [--color[=<when>] | --no-color] [--show-current]
-	[-v [--abbrev=<length> | --no-abbrev]]
+	[-v [--abbrev=<n> | --no-abbrev]]
 	[--column[=<options>] | --no-column] [--sort=<key>]
 	[--merged [<commit>]] [--no-merged [<commit>]]
 	[--contains [<commit>]] [--no-contains [<commit>]]
@@ -194,8 +194,10 @@ This option is only applicable in non-verbose mode.
 	Be more quiet when creating or deleting a branch, suppressing
 	non-error messages.
 
---abbrev=<length>::
-	Alter the sha1's minimum display length in the output listing.
+--abbrev=<n>::
+	In the verbose listing that show the commit object name,
+	use <n>, or as many hexdigits as needed to form a unique
+	object name.
 	The default value is 7 and can be overridden by the `core.abbrev`
 	config option.
 
diff --git a/Documentation/git-ls-files.txt b/Documentation/git-ls-files.txt
index 3cb2ebb438..60e3063fed 100644
--- a/Documentation/git-ls-files.txt
+++ b/Documentation/git-ls-files.txt
@@ -19,7 +19,7 @@ SYNOPSIS
 		[--exclude-standard]
 		[--error-unmatch] [--with-tree=<tree-ish>]
 		[--full-name] [--recurse-submodules]
-		[--abbrev] [--] [<file>...]
+		[--abbrev[=<n>]] [--] [<file>...]
 
 DESCRIPTION
 -----------
@@ -153,7 +153,8 @@ a space) at the start of each line:
 
 --abbrev[=<n>]::
 	Instead of showing the full 40-byte hexadecimal object
-	lines, show only a partial prefix.
+	lines, show <n>, or as many hexadecimal digits
+	as needed, to form a unique object name.
 	Non default number of digits can be specified with --abbrev=<n>.
 
 --debug::
diff --git a/Documentation/git-ls-tree.txt b/Documentation/git-ls-tree.txt
index a7515714da..480c668d0f 100644
--- a/Documentation/git-ls-tree.txt
+++ b/Documentation/git-ls-tree.txt
@@ -62,7 +62,8 @@ OPTIONS
 
 --abbrev[=<n>]::
 	Instead of showing the full 40-byte hexadecimal object
-	lines, show only a partial prefix.
+	lines, show <n>, or as many hexadecimal digits
+	as needed, to form a unique object name.
 	Non default number of digits can be specified with --abbrev=<n>.
 
 --full-name::
diff --git a/Documentation/pretty-options.txt b/Documentation/pretty-options.txt
index 17c5aac4b7..da6ab0de0c 100644
--- a/Documentation/pretty-options.txt
+++ b/Documentation/pretty-options.txt
@@ -16,7 +16,8 @@ configuration (see linkgit:git-config[1]).
 
 --abbrev-commit::
 	Instead of showing the full 40-byte hexadecimal commit object
-	name, show only a partial prefix.  Non default number of
+	name, show only a partial prefix that names the object uniquely.
+	Non default number of
 	digits can be specified with "--abbrev=<n>" (which also modifies
 	diff output, if it is displayed).
 +
-- 
2.29.2-287-gba574db674
Previous: Junio C HamanoNext: Derrick Stolee
Message 3 of 7 in “Bug with --abbrev option in git log?”
  1. Mário GuimarãesNov 4, 2020
  2. Junio C HamanoNov 4, 2020
  3. doc: clarify that most --abbrev[=<n>] are about minimum lengthJunio C Hamano, Nov 4, 2020
  4. Derrick StoleeNov 4, 2020
  5. doc: clarify that --abbrev=<n> is about the minimum lengthJunio C Hamano, Nov 4, 2020
  6. Derrick StoleeNov 7, 2020
  7. Mário GuimarãesNov 4, 2020

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