tag: implicitly supply --list given another list-like option

Change the "tag" command to implicitly turn on its --list mode when
provided with a list-like option such as --contains, --points-at etc.

This is for consistency with how "branch" works. When "branch" is
given a list-like option, such as --contains, it implicitly provides
--list. Before this change "tag" would error out on those sorts of
invocations. I.e. while both of these worked for "branch":

    git branch --contains v2.8.0 <pattern>
    git branch --list --contains v2.8.0 <pattern>

Only the latter form worked for "tag":

    git tag --contains v2.8.0 '*rc*'
    git tag --list --contains v2.8.0 '*rc*'

Now "tag", like "branch", will implicitly supply --list when a
list-like option is provided, and no other conflicting non-list
options (such as -d) are present on the command-line.

Spelunking through the history via:

    git log --reverse -p -G'only allowed with' -- '*builtin*tag*c'

Reveals that there was no good reason for not allowing this in the
first place. The --contains option added in 32c35cfb1e ("git-tag: Add
--contains option", 2009-01-26) made this an error. All the other
subsequent list-like options that were added copied its pattern of
making this usage an error.

The only tests that break as a result of this change are tests that
were explicitly checking that this "branch-like" usage wasn't
permitted. Change those failing tests to check that this invocation
mode is permitted, add extra tests for the list-like options we
weren't testing, and tests to ensure that e.g. we don't toggle the
list mode in the presence of other conflicting non-list options.

With this change errors messages such as "--contains option is only
allowed with -l" don't make sense anymore, since options like
--contain turn on -l. Instead we error out when list-like options such
as --contain are used in conjunction with conflicting options such as
-d or -v.

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

1 files changed, 11 insertions, 6 deletions

diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 47d8733523..4d289f5dd5 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt
@@ -82,10 +82,11 @@ OPTIONS
 
 -n<num>::
 	<num> specifies how many lines from the annotation, if any,
-	are printed when using -l.
-	The default is not to print any annotation lines.
-	If no number is given to `-n`, only the first line is printed.
-	If the tag is not annotated, the commit message is displayed instead.
+	are printed when using -l. Implies `--list`.
++
+The default is not to print any annotation lines.
+If no number is given to `-n`, only the first line is printed.
+If the tag is not annotated, the commit message is displayed instead.
 
 -l::
 --list::
@@ -95,6 +96,10 @@ OPTIONS
 Running "git tag" without arguments also lists all tags. The pattern
 is a shell wildcard (i.e., matched using fnmatch(3)). Multiple
 patterns may be given; if any of them matches, the tag is shown.
++
+This option is implicitly supplied if any other list-like option such
+as `--contains` is provided. See the documentation for each of those
+options for details.
 
 --sort=<key>::
 	Sort based on the key given.  Prefix `-` to sort in
@@ -123,7 +128,7 @@ This option is only applicable when listing tags without annotation lines.
 
 --contains [<commit>]::
 	Only list tags which contain the specified commit (HEAD if not
-	specified).
+	specified). Implies `--list`.
 
 --merged [<commit>]::
 	Only list tags whose commits are reachable from the specified
@@ -134,7 +139,7 @@ This option is only applicable when listing tags without annotation lines.
 	commit (`HEAD` if not specified), incompatible with `--merged`.
 
 --points-at <object>::
-	Only list tags of the given object.
+	Only list tags of the given object. Implies `--list`.
 
 -m <msg>::
 --message=<msg>::