ref-filter: add --no-contains option to tag/branch/for-each-ref

Change the tag, branch & for-each-ref commands to have a --no-contains
option in addition to their longstanding --contains options.

This allows for finding the last-good rollout tag given a known-bad
<commit>. Given a hypothetically bad commit cf5c7253e0, the git
version to revert to can be found with this hacky two-liner:

    (git tag -l 'v[0-9]*'; git tag -l --contains cf5c7253e0 'v[0-9]*') |
        sort | uniq -c | grep -E '^ *1 ' | awk '{print $2}' | tail -n 10

With this new --no-contains option the same can be achieved with:

    git tag -l --no-contains cf5c7253e0 'v[0-9]*' | sort | tail -n 10

As the filtering machinery is shared between the tag, branch &
for-each-ref commands, implement this for those commands too. A
practical use for this with "branch" is e.g. finding branches which
were branched off between v2.8.0 and v2.10.0:

    git branch --contains v2.8.0 --no-contains v2.10.0

The "describe" command also has a --contains option, but its semantics
are unrelated to what tag/branch/for-each-ref use --contains for. A
--no-contains option for "describe" wouldn't make any sense, other
than being exactly equivalent to not supplying --contains at all,
which would be confusing at best.

Add a --without option to "tag" as an alias for --no-contains, for
consistency with --with and --contains.  The --with option is
undocumented, and possibly the only user of it is
Junio (<xmqqefy71iej.fsf@gitster.mtv.corp.google.com>). But it's
trivial to support, so let's do that.

The additions to the the test suite are inverse copies of the
corresponding --contains tests. With this change --no-contains for
tag, branch & for-each-ref is just as well tested as the existing
--contains option.

In addition to those tests, add a test for "tag" which asserts that
--no-contains won't find tree/blob tags, which is slightly
unintuitive, but consistent with how --contains works & is documented.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 22 insertions, 6 deletions

diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index e465298571..e4b5d5c3e1 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -11,7 +11,8 @@ SYNOPSIS
 'git branch' [--color[=<when>] | --no-color] [-r | -a]
 	[--list] [-v [--abbrev=<length> | --no-abbrev]]
 	[--column[=<options>] | --no-column]
-	[(--merged | --no-merged | --contains) [<commit>]] [--sort=<key>]
+	[(--merged | --no-merged) [<commit>]]
+	[--contains [<commit]] [--no-contains [<commit>]] [--sort=<key>]
 	[--points-at <object>] [--format=<format>] [<pattern>...]
 'git branch' [--set-upstream | --track | --no-track] [-l] [-f] <branchname> [<start-point>]
 'git branch' (--set-upstream-to=<upstream> | -u <upstream>) [<branchname>]
@@ -35,7 +36,7 @@ as branch creation.
 
 With `--contains`, shows only the branches that contain the named commit
 (in other words, the branches whose tip commits are descendants of the
-named commit).  With `--merged`, only branches merged into the named
+named commit), `--no-contains` inverts it. With `--merged`, only branches merged into the named
 commit (i.e. the branches whose tip commits are reachable from the named
 commit) will be listed.  With `--no-merged` only branches not merged into
 the named commit will be listed.  If the <commit> argument is missing it
@@ -213,6 +214,10 @@ start-point is either a local or remote-tracking branch.
 	Only list branches which contain the specified commit (HEAD
 	if not specified). Implies `--list`.
 
+--no-contains [<commit>]::
+	Only list branches which don't contain the specified commit
+	(HEAD if not specified). Implies `--list`.
+
 --merged [<commit>]::
 	Only list branches whose tips are reachable from the
 	specified commit (HEAD if not specified). Implies `--list`,
@@ -298,13 +303,16 @@ If you are creating a branch that you want to checkout immediately, it is
 easier to use the git checkout command with its `-b` option to create
 a branch and check it out with a single command.
 
-The options `--contains`, `--merged` and `--no-merged` serve three related
-but different purposes:
+The options `--contains`, `--no-contains`, `--merged` and `--no-merged`
+serve four related but different purposes:
 
 - `--contains <commit>` is used to find all branches which will need
   special attention if <commit> were to be rebased or amended, since those
   branches contain the specified <commit>.
 
+- `--no-contains <commit>` is the inverse of that, i.e. branches that don't
+  contain the specified <commit>.
+
 - `--merged` is used to find all branches which can be safely deleted,
   since those branches are fully contained by HEAD.
 
diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 4d55893712..03e187a105 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -11,7 +11,7 @@ SYNOPSIS
 'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
 		   [(--sort=<key>)...] [--format=<format>] [<pattern>...]
 		   [--points-at <object>] [(--merged | --no-merged) [<object>]]
-		   [--contains [<object>]]
+		   [--contains [<object>]] [--no-contains [<object>]]
 
 DESCRIPTION
 -----------
@@ -81,6 +81,10 @@ OPTIONS
 	Only list refs which contain the specified commit (HEAD if not
 	specified).
 
+--no-contains [<object>]::
+	Only list refs which don't contain the specified commit (HEAD
+	if not specified).
+
 --ignore-case::
 	Sorting and filtering refs are case insensitive.
 
diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index d5cdb18d96..1be6570c90 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt
@@ -12,7 +12,7 @@ SYNOPSIS
 'git tag' [-a | -s | -u <keyid>] [-f] [-m <msg> | -F <file>]
 	<tagname> [<commit> | <object>]
 'git tag' -d <tagname>...
-'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
+'git tag' [-n[<num>]] -l [--contains <commit>] [--contains <commit>] [--points-at <object>]
 	[--column[=<options>] | --no-column] [--create-reflog] [--sort=<key>]
 	[--format=<format>] [--[no-]merged [<commit>]] [<pattern>...]
 'git tag' -v [--format=<format>] <tagname>...
@@ -130,6 +130,10 @@ This option is only applicable when listing tags without annotation lines.
 	Only list tags which contain the specified commit (HEAD if not
 	specified). Implies `--list`.
 
+--no-contains [<commit>]::
+	Only list tags which don't contain the specified commit (HEAD if
+	not specified). Implies `--list`.
+
 --merged [<commit>]::
 	Only list tags whose commits are reachable from the specified
 	commit (`HEAD` if not specified), incompatible with `--no-merged`.