[PATCH v3] Documentation/notes: fill out the man page a little

[Jonathan Nieder <jrnieder@gmail.com>]

Add some basic information to the ‘git notes’ page, mostly by moving
over information from git-config.1.  In particular, clarify that the
GIT_NOTES_REWRITE_REFS environment variable overrides both
‘[notes "rewrite"] <command>’ and ‘[notes] rewriteRef’.

Also add a Configuration section to git-log.1 for the ‘git notes’
page to refer to.

Later it would be nice to merge some changes back to git-config.1,
but one thing at a time.

Based on advice from Johan, Thomas, and Jeff.

Acked-by: Johan Herland <johan@herland.net>
Acked-by: Thomas Rast <trast@student.ethz.ch>
Cc: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
This patch is meant to replace the jn/notes-doc branch in pu.
Interdiff from last round:

  diff --git a/Documentation/git-notes.txt b/Documentation/git-notes.txt
  index de63ef0..1d8eef1 100644
  --- a/Documentation/git-notes.txt
  +++ b/Documentation/git-notes.txt
  @@ -149,9 +149,12 @@ which operation triggered the update, and the commit authorship is
   determined according to the usual rules (see linkgit:git-commit[1]).
   These details may change in the future.
   
  -It is also permitted for a notes ref to point directly to a tree
  -object, in which case the history of the notes can be read with
  -`git log -p -g <refname>`.
  +Some notes refs may be "history-less", either because they point
  +directly to a tree instead of a commit, or because their commits are
  +truncated; the notes generated by textconv caching
  +(see linkgit:gitattributes[5]) are an example of the latter.
  +To see the local history of these refs, view the reflog with
  +`git log -g <refname>`.
   
   
   EXAMPLES
  @@ -191,8 +194,8 @@ CONFIGURATION
   core.notesRef::
   	Notes ref to read and manipulate instead of
   	`refs/notes/commits`.  Must be an unabbreviated ref name.
  -	This setting can be overridden through the environment and
  -	command line.
  +	This setting can be overridden by the 'GIT_NOTES_REF'
  +	environment variable or the `--ref` option.
   
   notes.displayRef::
   	Which ref (or refs, if a glob or specified more than once), in

Thomas Rast wrote:

> I admit I read the end result instead of
> the series to save myself some confusion.

There’s a good reason to combine patches if I’ve ever heard one.
Thanks for noticing.

Jonathan

 Documentation/config.txt    |   16 +---
 Documentation/git-log.txt   |   42 ++++++++++
 Documentation/git-notes.txt |  180 +++++++++++++++++++++++++++++++++++++------
 t/t3307-notes-man.sh        |   38 +++++++++
 4 files changed, 241 insertions(+), 35 deletions(-)
 create mode 100755 t/t3307-notes-man.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 8f86050..cc4bc20 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -518,18 +518,12 @@ check that makes sure that existing object files will not get overwritten.
 
 core.notesRef::
 	When showing commit messages, also show notes which are stored in
-	the given ref.  This ref is expected to contain files named
-	after the full SHA-1 of the commit they annotate.  The ref
-	must be fully qualified.
+	the given ref.  The ref must be fully qualified.  If the given
+	ref does not exist, it is not an error but means that no
+	notes should be printed.
 +
-If such a file exists in the given ref, the referenced blob is read, and
-appended to the commit message, separated by a "Notes (<refname>):"
-line (shortened to "Notes:" in the case of "refs/notes/commits").  If the
-given ref itself does not exist, it is not an error, but means that no
-notes should be printed.
-+
-This setting defaults to "refs/notes/commits", and can be overridden by
-the `GIT_NOTES_REF` environment variable.
+This setting defaults to "refs/notes/commits", and it can be overridden by
+the 'GIT_NOTES_REF' environment variable.  See linkgit:git-notes[1].
 
 core.sparseCheckout::
 	Enable "sparse checkout" feature. See section "Sparse checkout" in
diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt
index fb184ba..d7f6a9c 100644
--- a/Documentation/git-log.txt
+++ b/Documentation/git-log.txt
@@ -132,6 +132,48 @@ Discussion
 
 include::i18n.txt[]
 
+Configuration
+-------------
+
+See linkgit:git-config[1] for core variables and linkgit:git-diff[1]
+for settings related to diff generation.
+
+format.pretty::
+	Default for the `--format` option.  (See "PRETTY FORMATS" above.)
+	Defaults to "medium".
+
+i18n.logOutputEncoding::
+	Encoding to use when displaying logs.  (See "Discussion", above.)
+	Defaults to the value of `i18n.commitEncoding` if set, UTF-8
+	otherwise.
+
+log.date::
+	Default format for human-readable dates.  (Compare the
+	`--date` option.)  Defaults to "default", which means to write
+	dates like `Sat May 8 19:35:34 2010 -0500`.
+
+log.showroot::
+	If `false`, 'git log' and related commands will not treat the
+	initial commit as a big creation event.  Any root commits in
+	`git log -p` output would be shown without a diff attached.
+	The default is `true`.
+
+mailmap.file::
+	See linkgit:git-shortlog[1].
+
+notes.displayRef::
+	Which refs, in addition to the default set by `core.notesRef`
+	or 'GIT_NOTES_REF', to read notes from when showing commit
+	messages with the 'log' family of commands.  See
+	linkgit:git-notes[1].
++
+May be an unabbreviated ref name or a glob and may be specified
+multiple times.  A warning will be issued for refs that do not exist,
+but a glob that does not match any refs is silently ignored.
++
+This setting can be disabled by the `--no-standard-notes` option,
+overridden by the 'GIT_NOTES_DISPLAY_REF' environment variable,
+and supplemented by the `--show-notes` option.
 
 Author
 ------
diff --git a/Documentation/git-notes.txt b/Documentation/git-notes.txt
index 4e5113b..1d8eef1 100644
--- a/Documentation/git-notes.txt
+++ b/Documentation/git-notes.txt
@@ -3,7 +3,7 @@ git-notes(1)
 
 NAME
 ----
-git-notes - Add/inspect object notes
+git-notes - Add or inspect object notes
 
 SYNOPSIS
 --------
@@ -20,24 +20,26 @@ SYNOPSIS
 
 DESCRIPTION
 -----------
-This command allows you to add/remove notes to/from objects, without
-changing the objects themselves.
+Adds, removes, or reads notes attached to objects, without touching
+the objects themselves.
 
-A typical use of notes is to extend a commit message without having
-to change the commit itself. Such commit notes can be shown by `git log`
-along with the original commit message. To discern these notes from the
+By default, notes are saved to and read from `refs/notes/commits`, but
+this default can be overridden.  See the OPTIONS, CONFIGURATION, and
+ENVIRONMENT sections below.  If this ref does not exist, it will be
+quietly created when it is first needed to store a note.
+
+A typical use of notes is to supplement a commit message without
+changing the commit itself. Notes can be shown by 'git log' along with
+the original commit message. To distinguish these notes from the
 message stored in the commit object, the notes are indented like the
 message, after an unindented line saying "Notes (<refname>):" (or
-"Notes:" for the default setting).
+"Notes:" for `refs/notes/commits`).
 
-This command always manipulates the notes specified in "core.notesRef"
-(see linkgit:git-config[1]), which can be overridden by GIT_NOTES_REF.
-To change which notes are shown by 'git-log', see the
-"notes.displayRef" configuration.
+To change which notes are shown by 'git log', see the
+"notes.displayRef" configuration in linkgit:git-log[1].
 
-See the description of "notes.rewrite.<command>" in
-linkgit:git-config[1] for a way of carrying your notes across commands
-that rewrite commits.
+See the "notes.rewrite.<command>" configuration for a way to carry
+notes across commands that rewrite commits.
 
 
 SUBCOMMANDS
@@ -101,15 +103,20 @@ OPTIONS
 	Use the given note message (instead of prompting).
 	If multiple `-m` options are given, their values
 	are concatenated as separate paragraphs.
+	Lines starting with `#` and empty lines other than a
+	single line between paragraphs will be stripped out.
 
 -F <file>::
 --file=<file>::
 	Take the note message from the given file.  Use '-' to
 	read the note message from the standard input.
+	Lines starting with `#` and empty lines other than a
+	single line between paragraphs will be stripped out.
 
 -C <object>::
 --reuse-message=<object>::
-	Reuse the note message from the given note object.
+	Take the note message from the given blob object (for
+	example, another note).
 
 -c <object>::
 --reedit-message=<object>::
@@ -117,22 +124,147 @@ OPTIONS
 	the user can further edit the note message.
 
 --ref <ref>::
-	Manipulate the notes tree in <ref>.  This overrides both
-	GIT_NOTES_REF and the "core.notesRef" configuration.  The ref
+	Manipulate the notes tree in <ref>.  This overrides
+	'GIT_NOTES_REF' and the "core.notesRef" configuration.  The ref
 	is taken to be in `refs/notes/` if it is not qualified.
 
 
-NOTES
------
+DISCUSSION
+----------
+
+Commit notes are blobs containing extra information about an object
+(usually information to supplement a commit's message).  These blobs
+are taken from notes refs.  A notes ref is usually a branch which
+contains "files" whose paths are the object names for the objects
+they describe, with some directory separators included for performance
+reasons footnote:[Permitted pathnames have the form
+'ab'`/`'cd'`/`'ef'`/`'...'`/`'abcdef...': a sequence of directory
+names of two hexadecimal digits each followed by a filename with the
+rest of the object ID.].
 
 Every notes change creates a new commit at the specified notes ref.
 You can therefore inspect the history of the notes by invoking, e.g.,
-`git log -p notes/commits`.
+`git log -p notes/commits`.  Currently the commit message only records
+which operation triggered the update, and the commit authorship is
+determined according to the usual rules (see linkgit:git-commit[1]).
+These details may change in the future.
 
-Currently the commit message only records which operation triggered
-the update, and the commit authorship is determined according to the
-usual rules (see linkgit:git-commit[1]).  These details may change in
-the future.
+Some notes refs may be "history-less", either because they point
+directly to a tree instead of a commit, or because their commits are
+truncated; the notes generated by textconv caching
+(see linkgit:gitattributes[5]) are an example of the latter.
+To see the local history of these refs, view the reflog with
+`git log -g <refname>`.
+
+
+EXAMPLES
+--------
+
+You can use notes to add annotations with information that was not
+available at the time a commit was written.
+
+------------
+$ git notes add -m 'Tested-by: Johannes Sixt <j6t@kdbg.org>' 72a144e2
+$ git show -s 72a144e
+[...]
+    Signed-off-by: Junio C Hamano <gitster@pobox.com>
+
+Notes:
+    Tested-by: Johannes Sixt <j6t@kdbg.org>
+------------
+
+In principle, a note is a regular Git blob, and any kind of
+(non-)format is accepted.  You can binary-safely create notes from
+arbitrary files using 'git hash-object':
+
+------------
+$ cc *.c
+$ blob=$(git hash-object -w a.out)
+$ git notes --ref=built add -C "$blob" HEAD
+------------
+
+Of course, it doesn't make much sense to display non-text-format notes
+with 'git log', so if you use such notes, you'll probably need to write
+some special-purpose tools to do something useful with them.
+
+
+CONFIGURATION
+-------------
+
+core.notesRef::
+	Notes ref to read and manipulate instead of
+	`refs/notes/commits`.  Must be an unabbreviated ref name.
+	This setting can be overridden by the 'GIT_NOTES_REF'
+	environment variable or the `--ref` option.
+
+notes.displayRef::
+	Which ref (or refs, if a glob or specified more than once), in
+	addition to the default set by `core.notesRef` or
+	'GIT_NOTES_REF', to read notes from when showing commit
+	messages with the 'git log' family of commands.
+	This setting can be overridden on the command line or by the
+	'GIT_NOTES_DISPLAY_REF' environment variable.
+	See linkgit:git-log[1].
+
+notes.rewrite.<command>::
+	When rewriting commits with <command> (currently `amend` or
+	`rebase`), if this variable is `false`, git will not copy
+	notes from the original to the rewritten commit.  Defaults to
+	`true`.  See also "`notes.rewriteRef`" below.
++
+This setting can be overridden by the 'GIT_NOTES_REWRITE_REF'
+environment variable.
+
+notes.rewriteMode::
+	When copying notes during a rewrite, what to do if the target
+	commit already has a note.  Must be one of `overwrite`,
+	`concatenate`, and `ignore`.  Defaults to `concatenate`.
++
+This setting can be overridden with the `GIT_NOTES_REWRITE_MODE`
+environment variable.
+
+notes.rewriteRef::
+	When copying notes during a rewrite, specifies the (fully
+	qualified) ref whose notes should be copied.  May be a glob,
+	in which case notes in all matching refs will be copied.  You
+	may also specify this configuration several times.
++
+Does not have a default value; you must configure this variable to
+enable note rewriting.
++
+Can be overridden with the 'GIT_NOTES_REWRITE_REF' environment variable.
+
+
+ENVIRONMENT
+-----------
+
+'GIT_NOTES_REF'::
+	Which ref to manipulate notes from, instead of `refs/notes/commits`.
+	This overrides the `core.notesRef` setting.
+
+'GIT_NOTES_DISPLAY_REF'::
+	Colon-delimited list of refs or globs indicating which refs,
+	in addition to the default from `core.notesRef` or
+	'GIT_NOTES_REF', to read notes from when showing commit
+	messages.
+	This overrides the `notes.displayRef` setting.
++
+A warning will be issued for refs that do not exist, but a glob that
+does not match any refs is silently ignored.
+
+'GIT_NOTES_REWRITE_MODE'::
+	When copying notes during a rewrite, what to do if the target
+	commit already has a note.
+	Must be one of `overwrite`, `concatenate`, and `ignore`.
+	This overrides the `core.rewriteMode` setting.
+
+'GIT_NOTES_REWRITE_REF'::
+	When rewriting commits, which notes to copy from the original
+	to the rewritten commit.  Must be a colon-delimited list of
+	refs or globs.
++
+If not set in the environment, the list of notes to copy depends
+on the `notes.rewrite.<command>` and `notes.rewriteRef` settings.
 
 
 Author
diff --git a/t/t3307-notes-man.sh b/t/t3307-notes-man.sh
new file mode 100755
index 0000000..3269f2e
--- /dev/null
+++ b/t/t3307-notes-man.sh
@@ -0,0 +1,38 @@
+#!/bin/sh
+
+test_description='Examples from the git-notes man page
+
+Make sure the manual is not full of lies.'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit A &&
+	test_commit B &&
+	test_commit C
+'
+
+test_expect_success 'example 1: notes to add an Acked-by line' '
+	cat <<-\EOF >expect &&
+	    B
+
+	Notes:
+	    Acked-by: A C Ker <acker@example.com>
+	EOF
+	git notes add -m "Acked-by: A C Ker <acker@example.com>" B &&
+	git show -s B^{commit} >log &&
+	tail -n 4 log >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'example 2: binary notes' '
+	cp "$TEST_DIRECTORY"/test4012.png .
+	git checkout B &&
+	blob=$(git hash-object -w test4012.png) &&
+	git notes --ref=logo add -C "$blob" &&
+	git notes --ref=logo copy B C &&
+	git notes --ref=logo show C >actual &&
+	test_cmp test4012.png actual
+'
+
+test_done
-- 
1.7.1