Thanks for looking after this.
On Tue, Dec 11, 2012 at 1:58 PM, W. Trevor King <wking@xxxxxxxxxx> wrote:
> From: "W. Trevor King" <wking@xxxxxxxxxx>
>
> The current `update` command incorporates the superproject's gitlinked
> SHA-1 ($sha1) into the submodule HEAD ($subsha1). Depending on the
> options you use, it may checkout $sha1, rebase the $subsha1 onto
> $sha1, or merge $sha1 into $subsha1. This helps you keep up with
> changes in the upstream superproject.
>
> However, it's also useful to stay up to date with changes in the
> upstream subproject. Previous workflows for incorporating such
> changes include the ungainly:
>
> $ git submodule foreach 'git checkout $(git config --file $toplevel/.gitmodules submodule.$name.branch) && git pull'
>
> With this patch, all of the useful functionality for incorporating
> superproject changes can be reused to incorporate upstream subproject
> updates. When you specify --remote, the target $sha1 is replaced with
> a $sha1 of the submodule's origin/master tracking branch. If you want
> to merge a different tracking branch, you can configure the
> `submodule.<name>.branch` option in `.gitmodules`. You can override
> the `.gitmodules` configuration setting for a particular superproject
> by configuring the option in that superproject's default configuration
> (using the usual configuration hierarchy, e.g. `.git/config`,
> `~/.gitconfig`, etc.).
>
> Previous use of submodule.<name>.branch
> =======================================
>
> Because we're adding a new configuration option, it's a good idea to
> check if anyone else is already using the option. The foreach-pull
> example above was described by Ævar in
>
> commit f030c96d8643fa0a1a9b2bd9c2f36a77721fb61f
> Author: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
> Date: Fri May 21 16:10:10 2010 +0000
>
> git-submodule foreach: Add $toplevel variable
>
> Gerrit uses the same interpretation for the setting, but because
> Gerrit has direct access to the subproject repositories, it updates
> the superproject repositories automatically when a subproject changes.
> Gerrit also accepts the special value '.', which it expands into the
> superproject's branch name.
>
> Although the --remote functionality is using `submodule.<name>.branch`
> slightly differently, the effect is the same. The foreach-pull
> example uses the option to record the name of the local branch to
> checkout before pulls. The tracking branch to be pulled is recorded
> in `.git/modules/<name>/config`, which was initialized by the module
> clone during `submodule add` or `submodule init`. Because the branch
> name stored in `submodule.<name>.branch` was likely the same as the
> branch name used during the initial `submodule add`, the same branch
> will be pulled in each workflow.
>
> Implementation details
> ======================
>
> In order to ensure a current tracking branch state, `update --remote`
> fetches the submodule's remote repository before calculating the
> SHA-1. However, I didn't change the logic guarding the existing fetch:
>
> if test -z "$nofetch"
> then
> # Run fetch only if $sha1 isn't present or it
> # is not reachable from a ref.
> (clear_local_git_env; cd "$path" &&
> ( (rev=$(git rev-list -n 1 $sha1 --not --all 2>/dev/null) &&
> test -z "$rev") || git-fetch)) ||
> die "$(eval_gettext "Unable to fetch in submodule path '\$path'")"
> fi
>
> There will not be a double-fetch, because the new $sha1 determined
> after the `--remote` triggered fetch should always exist in the
> repository. If it doesn't, it's because some racy process removed it
> from the submodule's repository and we *should* be re-fetching.
>
> Signed-off-by: W. Trevor King <wking@xxxxxxxxxx>
> ---
> Documentation/config.txt | 7 ++++++-
> Documentation/git-submodule.txt | 25 ++++++++++++++++++++++++-
> Documentation/gitmodules.txt | 5 +++++
> git-submodule.sh | 22 +++++++++++++++++++++-
> t/t7406-submodule-update.sh | 31 +++++++++++++++++++++++++++++++
> 5 files changed, 87 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index 11f320b..6f4663c 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -1998,7 +1998,12 @@ submodule.<name>.update::
> for a submodule. These variables are initially populated
> by 'git submodule init'; edit them to override the
> URL and other values found in the `.gitmodules` file. See
> - linkgit:git-submodule[1] and linkgit:gitmodules[5] for details.
> +
> +submodule.<name>.branch::
> + The remote branch name for a submodule, used by `git submodule
> + update --remote`. Set this option to override the value found in
> + the `.gitmodules` file. See linkgit:git-submodule[1] and
> + linkgit:gitmodules[5] for details.
>
> submodule.<name>.fetchRecurseSubmodules::
> This option can be used to control recursive fetching of this
> diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
> index b4683bb..72dd52f 100644
> --- a/Documentation/git-submodule.txt
> +++ b/Documentation/git-submodule.txt
> @@ -13,7 +13,7 @@ SYNOPSIS
> [--reference <repository>] [--] <repository> [<path>]
> 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
> 'git submodule' [--quiet] init [--] [<path>...]
> -'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase]
> +'git submodule' [--quiet] update [--init] [--remote] [-N|--no-fetch] [--rebase]
> [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
> 'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>]
> [commit] [--] [<path>...]
> @@ -236,6 +236,29 @@ OPTIONS
> (the default). This limit only applies to modified submodules. The
> size is always limited to 1 for added/deleted/typechanged submodules.
>
> +--remote::
> + This option is only valid for the update command. Instead of using
> + the superproject's recorded SHA-1 to update the submodule, use the
> + status of the submodule's remote tracking branch. The remote used
> + is branch's remote (`branch.<name>.remote`), defaulting to `origin`.
> + The remote branch used defaults to `master`, but the branch name may
> + be overridden by setting the `submodule.<name>.branch` option in
> + either `.gitmodules` or `.git/config` (with `.git/config` taking
> + precedence).
> ++
> +This works for any of the supported update procedures (`--checkout`,
> +`--rebase`, etc.). The only change is the source of the target SHA-1.
> +For example, `submodule update --remote --merge` will merge upstream
> +submodule changes into the submodules, while `submodule update
> +--merge` will merge superproject gitlink changes into the submodules.
> ++
> +In order to ensure a current tracking branch state, `update --remote`
> +fetches the submodule's remote repository before calculating the
> +SHA-1. This makes `submodule update --remote --merge` similar to
> +running `git pull` in the submodule. If you don't want to fetch (for
> +something closer to `git merge`), you should use `submodule update
> +--remote --no-fetch --merge`.
I assume the same can be said for 'submodue update --remote --rebase',
right? I wonder if this can be made merge/rebase-agnostic. Is it
still true if I word it like this?:
In order to ensure a current tracking branch state, `update --remote`
fetches the submodule's remote repository before calculating the
SHA-1. If you don't want to fetch, you should use `submodule update
--remote --no-fetch`.
> +
> -N::
> --no-fetch::
> This option is only valid for the update command.
> diff --git a/Documentation/gitmodules.txt b/Documentation/gitmodules.txt
> index 4effd78..4004fa6 100644
> --- a/Documentation/gitmodules.txt
> +++ b/Documentation/gitmodules.txt
> @@ -47,6 +47,11 @@ submodule.<name>.update::
> This config option is overridden if 'git submodule update' is given
> the '--merge', '--rebase' or '--checkout' options.
>
> +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.
> +
> submodule.<name>.fetchRecurseSubmodules::
> This option can be used to control recursive fetching of this
> submodule. If this option is also present in the submodules entry in
> diff --git a/git-submodule.sh b/git-submodule.sh
> index f969f28..1395079 100755
> --- a/git-submodule.sh
> +++ b/git-submodule.sh
> @@ -8,7 +8,8 @@ dashless=$(basename "$0" | sed -e 's/-/ /')
> USAGE="[--quiet] add [-b branch] [-f|--force] [--reference <repository>] [--] <repository> [<path>]
> or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
> or: $dashless [--quiet] init [--] [<path>...]
> - or: $dashless [--quiet] update [--init] [-N|--no-fetch] [-f|--force] [--rebase] [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
> + or: $dashless [--quiet] update [--init] [--remote] [-N|--no-fetch] [-f|--force] [--rebase] [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
> +ges
I think there's an unintentionally added line here with "ges".
> or: $dashless [--quiet] summary [--cached|--files] [--summary-limit <n>] [commit] [--] [<path>...]
> or: $dashless [--quiet] foreach [--recursive] <command>
> or: $dashless [--quiet] sync [--] [<path>...]"
> @@ -26,6 +27,7 @@ cached=
> recursive=
> init=
> files=
> +remote=
> nofetch=
> update=
> prefix=
> @@ -535,6 +537,9 @@ cmd_update()
> -i|--init)
> init=1
> ;;
> + --remote)
> + remote=1
> + ;;
> -N|--no-fetch)
> nofetch=1
> ;;
> @@ -595,6 +600,7 @@ cmd_update()
> fi
> name=$(module_name "$sm_path") || exit
> url=$(git config submodule."$name".url)
> + branch=$(get_submodule_config "$name" branch master)
> if ! test -z "$update"
> then
> update_module=$update
> @@ -629,6 +635,20 @@ Maybe you want to use 'update --init'?")"
> die "$(eval_gettext "Unable to find current revision in submodule path '\$sm_path'")"
> fi
>
> + if test -n "$remote"
> + then
> + if test -z "$nofetch"
> + then
> + # Fetch remote before determining tracking $sha1
> + (clear_local_git_env; cd "$sm_path" && git-fetch) ||
You should 'git fetch $remote_name' here, and of course, initialize
remote_name before this. But how can we know the remote_name in the
first place? Is it safe to assume the submodule remote names will
match those in the superproject?
> + die "$(eval_gettext "Unable to fetch in submodule path '\$sm_path'")"
> + fi
> + remote_name=$(get_default_remote)
This get_default_remote finds the remote for the remote-tracking
branch for HEAD in the superproject. It is possible that HEAD !=
$branch, so we have very few clues to go on here to get a more
reasonable answer, so I do not have any good suggestions to improve
this.
One option would be to find the remote given for
submodule."$branch".merge, but this would suppose there is some
remote-tracking branch configured in the submodule, and that is not
likely to be the case.
> + sha1=$(clear_local_git_env; cd "$sm_path" &&
> + git rev-parse --verify "${remote_name}/${branch}") ||
This does assume the submodule remote names will match those in the
superproject. Is this safe?
> + die "$(eval_gettext "Unable to find current ${remote_name}/${branch} revision in submodule path '\$sm_path'")"
> + fi
> +
> if test "$subsha1" != "$sha1" -o -n "$force"
> then
> subforce=$force
> diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
> index 1542653..a567834 100755
> --- a/t/t7406-submodule-update.sh
> +++ b/t/t7406-submodule-update.sh
> @@ -135,6 +135,37 @@ test_expect_success 'submodule update --force forcibly checks out submodules' '
> )
> '
>
> +test_expect_success 'submodule update --remote should fetch upstream changes' '
> + (cd submodule &&
> + echo line4 >> file &&
> + git add file &&
> + test_tick &&
> + git commit -m "upstream line4"
> + ) &&
> + (cd super &&
> + git submodule update --remote --force submodule &&
> + cd submodule &&
> + test "$(git log -1 --oneline)" = "$(GIT_DIR=../../submodule/.git git log -1 --oneline)"
> + )
> +'
> +
> +test_expect_success 'local config should override .gitmodules branch' '
> + (cd submodule &&
> + git checkout -b test-branch &&
> + echo line5 >> file &&
> + git add file &&
> + test_tick &&
> + git commit -m "upstream line5" &&
> + git checkout master
> + ) &&
> + (cd super &&
> + git config submodule.submodule.branch test-branch &&
> + git submodule update --remote --force submodule &&
> + cd submodule &&
> + test "$(git log -1 --oneline)" = "$(GIT_DIR=../../submodule/.git git log -1 --oneline test-branch)"
> + )
> +'
> +
> test_expect_success 'submodule update --rebase staying on master' '
> (cd super/submodule &&
> git checkout master
> --
> 1.8.0
>
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