submodule: explicit local branch creation in module_clone

The previous code only checked out branches in cmd_add.  This commit
moves the branch-checkout logic into module_clone, where it can be
shared by cmd_add and cmd_update.  I also update the initial checkout
command to use 'reset' to preserve branches setup during module_clone.

With this change, folks cloning submodules for the first time via:

  $ git submodule update ...

will get a local branch instead of a detached HEAD, unless they are
using the default checkout-mode updates.  This is a change from the
previous situation where cmd_update always used checkout-mode logic
(regardless of the requested update mode) for updates that triggered
an initial clone, which always resulted in a detached HEAD.

This commit does not change the logic for updates after the initial
clone, which will continue to create detached HEADs for checkout-mode
updates, and integrate remote work with the local HEAD (detached or
not) in other modes.

The motivation for the change is that developers doing local work
inside the submodule are likely to select a non-checkout-mode for
updates so their local work is integrated with upstream work.
Developers who are not doing local submodule work stick with
checkout-mode updates so any apparently local work is blown away
during updates.  For example, if upstream rolls back the remote branch
or gitlinked commit to an earlier version, the checkout-mode developer
wants their old submodule checkout to be rolled back as well, instead
of getting a no-op merge/rebase with the rolled-back reference.

By using the update mode to distinguish submodule developers from
black-box submodule consumers, we can setup local branches for the
developers who will want local branches, and stick with detached HEADs
for the developers that don't care.

Testing
=======

In t7406, just-cloned checkouts now update to the gitlinked hash with
'reset', to preserve the local branch for situations where we're not
on a detached HEAD.

I also added explicit tests to t7406 for HEAD attachement after
cloning updates, showing that it depends on their update mode:

* Checkout-mode updates get detached HEADs
* Everyone else gets a local branch, matching the configured
  submodule.<name>.branch and defaulting to master.

The 'initial-setup' tag makes it easy to reset the superproject to a
known state, as several earlier tests commit to submodules and commit
the changed gitlinks to the superproject, but don't push the new
submodule commits to the upstream subprojects.  This makes it
impossible to checkout the current super master, because it references
submodule commits that don't exist in the upstream subprojects.  For a
specific example, see the tests that currently generate the
'two_new_submodule_commits' commits.

Documentation
=============

I updated the docs to describe the 'submodule update' modes in detail.
The old documentation did not distinguish between cloning and
non-cloning updates and lacked clarity on which operations would lead
to detached HEADs, and which would not.  The new documentation
addresses these issues while updating the docs to reflect the changes
introduced by this commit's explicit local branch creation in
module_clone.

I also add '--checkout' to the usage summary and group the update-mode
options into a single set.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
W. Trevor King 2014-01-26 12:45:15 -08:00 committed by Junio C Hamano
parent 9adfc1cfa7
commit 23d25e48f5
4 changed files with 110 additions and 27 deletions

View File

@ -15,8 +15,8 @@ SYNOPSIS
'git submodule' [--quiet] init [--] [<path>...]
'git submodule' [--quiet] deinit [-f|--force] [--] <path>...
'git submodule' [--quiet] update [--init] [--remote] [-N|--no-fetch]
[-f|--force] [--rebase] [--reference <repository>] [--depth <depth>]
[--merge] [--recursive] [--] [<path>...]
[-f|--force] [--rebase|--merge|--checkout] [--reference <repository>]
[--depth <depth>] [--recursive] [--] [<path>...]
'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>]
[commit] [--] [<path>...]
'git submodule' [--quiet] foreach [--recursive] <command>
@ -155,13 +155,31 @@ it contains local modifications.
update::
Update the registered submodules, i.e. clone missing submodules and
checkout the commit specified in the index of the containing repository.
This will make the submodules HEAD be detached unless `--rebase` or
`--merge` is specified or the key `submodule.$name.update` is set to
`rebase`, `merge` or `none`. `none` can be overridden by specifying
`--checkout`. Setting the key `submodule.$name.update` to `!command`
will cause `command` to be run. `command` can be any arbitrary shell
command that takes a single argument, namely the sha1 to update to.
checkout the commit specified in the index of the containing
repository. The update mode defaults to `checkout`, but can be
configured with the `submodule.<name>.update` setting or the
`--rebase`, `--merge`, or `--checkout` options.
+
For updates that clone missing submodules, checkout-mode updates will
create submodules with detached HEADs; all other modes will create
submodules with a local branch named after `submodule.<path>.branch`.
+
For updates that do not clone missing submodules, the submodule's HEAD
is only touched when the remote reference does not match the
submodule's HEAD (for none-mode updates, the submodule is never
touched). The remote reference is usually the gitlinked commit from
the superproject's tree, but with `--remote` it is the upstream
subproject's `submodule.<name>.branch`. This remote reference is
integrated with the submodule's HEAD using the specified update mode.
For checkout-mode updates, that will result in a detached HEAD. For
rebase- and merge-mode updates, the commit referenced by the
submodule's HEAD may change, but the symbolic reference will remain
unchanged (i.e. checked-out branches will still be checked-out
branches, and detached HEADs will still be detached HEADs). If none
of the builtin modes fit your needs, set `submodule.<name>.update` to
`!command` to configure a custom integration command. `command` can
be any arbitrary shell command that takes a single argument, namely
the sha1 to update to.
+
If the submodule is not yet initialized, and you just want to use the
setting as stored in .gitmodules, you can automatically initialize the

View File

@ -53,6 +53,10 @@ submodule.<name>.branch::
A remote branch name for tracking updates in the upstream submodule.
If the option is not specified, it defaults to 'master'. See the
`--remote` documentation in linkgit:git-submodule[1] for details.
+
This branch name is also used for the local branch created by
non-checkout cloning updates. See the `update` documentation in
linkgit:git-submodule[1] for details.
submodule.<name>.fetchRecurseSubmodules::
This option can be used to control recursive fetching of this

View File

@ -246,6 +246,9 @@ module_name()
# $3 = URL to clone
# $4 = reference repository to reuse (empty for independent)
# $5 = depth argument for shallow clones (empty for deep)
# $6 = (remote-tracking) starting point for the local branch (empty for HEAD)
# $7 = local branch to create (empty for a detached HEAD, unless $6 is
# also empty, in which case the local branch is left unchanged)
#
# Prior to calling, cmd_update checks that a possibly existing
# path is not a git repository.
@ -259,6 +262,8 @@ module_clone()
url=$3
reference="$4"
depth="$5"
start_point="$6"
local_branch="$7"
quiet=
if test -n "$GIT_QUIET"
then
@ -312,7 +317,16 @@ module_clone()
echo "gitdir: $rel/$a" >"$sm_path/.git"
rel=$(echo $a | sed -e 's|[^/][^/]*|..|g')
(clear_local_git_env; cd "$sm_path" && GIT_WORK_TREE=. git config core.worktree "$rel/$b")
(
clear_local_git_env
cd "$sm_path" &&
GIT_WORK_TREE=. git config core.worktree "$rel/$b" &&
# ash fails to wordsplit ${local_branch:+-B "$local_branch"...}
case "$local_branch" in
'') git checkout -f -q ${start_point:+"$start_point"} ;;
?*) git checkout -f -q -B "$local_branch" ${start_point:+"$start_point"} ;;
esac
) || die "$(eval_gettext "Unable to setup cloned submodule '\$sm_path'")"
}
isnumber()
@ -475,16 +489,15 @@ Use -f if you really want to add it." >&2
echo "$(eval_gettext "Reactivating local git directory for submodule '\$sm_name'.")"
fi
fi
module_clone "$sm_path" "$sm_name" "$realrepo" "$reference" "$depth" || exit
(
clear_local_git_env
cd "$sm_path" &&
# ash fails to wordsplit ${branch:+-b "$branch"...}
case "$branch" in
'') git checkout -f -q ;;
?*) git checkout -f -q -B "$branch" "origin/$branch" ;;
esac
) || die "$(eval_gettext "Unable to checkout submodule '\$sm_path'")"
if test -n "$branch"
then
start_point="origin/$branch"
local_branch="$branch"
else
start_point=""
local_branch=""
fi
module_clone "$sm_path" "$sm_name" "$realrepo" "$reference" "$depth" "$start_point" "$local_branch" || exit
fi
git config submodule."$sm_name".url "$realrepo"
@ -803,7 +816,9 @@ cmd_update()
fi
name=$(module_name "$sm_path") || exit
url=$(git config submodule."$name".url)
branch=$(get_submodule_config "$name" branch master)
config_branch=$(get_submodule_config "$name" branch)
branch="${config_branch:-master}"
local_branch="$branch"
if ! test -z "$update"
then
update_module=$update
@ -817,11 +832,19 @@ cmd_update()
displaypath=$(relative_path "$prefix$sm_path")
if test "$update_module" = "none"
then
case "$update_module" in
none)
echo "Skipping submodule '$displaypath'"
continue
fi
;;
checkout)
local_branch=""
;;
rebase | merge | !*)
;;
*)
die "$(eval_gettext "Invalid update mode '$update_module' for submodule '$name'")"
esac
if test -z "$url"
then
@ -835,7 +858,8 @@ Maybe you want to use 'update --init'?")"
if ! test -d "$sm_path"/.git -o -f "$sm_path"/.git
then
module_clone "$sm_path" "$name" "$url" "$reference" "$depth" || exit
start_point="origin/${branch}"
module_clone "$sm_path" "$name" "$url" "$reference" "$depth" "$start_point" "$local_branch" || exit
cloned_modules="$cloned_modules;$name"
subsha1=
else
@ -881,7 +905,7 @@ Maybe you want to use 'update --init'?")"
case ";$cloned_modules;" in
*";$name;"*)
# then there is no local change to integrate
update_module=checkout ;;
update_module='!git reset --hard -q'
esac
must_die_on_failure=

View File

@ -63,6 +63,9 @@ test_expect_success 'setup a submodule tree' '
git submodule add ../none none &&
test_tick &&
git commit -m "none"
) &&
(cd super &&
git tag initial-setup
)
'
@ -703,7 +706,7 @@ test_expect_success 'submodule update places git-dir in superprojects git-dir re
git clone super_update_r super_update_r2 &&
(cd super_update_r2 &&
git submodule update --init --recursive >actual &&
test_i18ngrep "Submodule path .submodule/subsubmodule.: checked out" actual &&
test_i18ngrep "Submodule path .submodule/subsubmodule.: .git reset --hard -q" actual &&
(cd submodule/subsubmodule &&
git log > ../../expected
) &&
@ -764,4 +767,38 @@ test_expect_success 'submodule update clone shallow submodule' '
)
)
'
test_expect_success 'submodule update --checkout clones detached HEAD' '
git clone super super4 &&
echo "detached HEAD" >expected &&
(cd super4 &&
git reset --hard initial-setup &&
git submodule init submodule &&
git submodule update >> /tmp/log 2>&1 &&
(cd submodule &&
git symbolic-ref HEAD > ../../actual ||
echo "detached HEAD" > ../../actual
)
) &&
test_cmp actual expected &&
rm -rf super4
'
test_expect_success 'submodule update --merge clones attached HEAD' '
git clone super super4 &&
echo "refs/heads/master" >expected &&
(cd super4 &&
git reset --hard initial-setup &&
git submodule init submodule &&
git config submodule.submodule.update merge &&
git submodule update --merge &&
(cd submodule &&
git symbolic-ref HEAD > ../../actual ||
echo "detached HEAD" > ../../actual
)
) &&
test_cmp actual expected &&
rm -rf super4
'
test_done