[GHC] #8251: Validate submodule references during pre-receive hook

[GHC]

#8251: Validate submodule references during pre-receive hook
-------------------------------------+------------------------------------
        Reporter:  hvr               |            Owner:  hvr
            Type:  task              |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Trac & Git        |          Version:  7.6.3
      Resolution:                    |         Keywords:  admin git
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
-------------------------------------+------------------------------------

Comment (by hvr):

 Here's a sample session demonstrating the new server-side validation
 checks, when trying to update the `Win32` package to version 2.3.0.2 (from
 previously 2.3.0.1);

 After having synced up `libraries/Win32` to point version 2.3.0.2 of
 `Win32` we have the following change to commit to `ghc.git` (`git add
 libaries/Win32`):
 {{{#!diff
 diff --git a/libraries/Win32 b/libraries/Win32
 index 1e909ad..c51e81a 160000
 --- a/libraries/Win32
 +++ b/libraries/Win32
 @@ -1 +1 @@
 -Subproject commit 1e909adb06b766e107148b8b37a4a9f9e50baf74
 +Subproject commit c51e81a43cd5e9540453bd5ca6da8992245a4774
 }}}

 1. Pushing a commit touching a submodule ref w/o including the
 "`submodule`" safe-word:
 {{{
 $ git commit -s -m "Update Win32-2.3.0.2"
 $ git push
 ...
 remote: performing tab-check...
 remote: performing submodule-ref update validations...
 remote: Submodule update(s) detected in
 ff458fc260fd05ebcb7db3294cbb1ec623e6525e:
 remote: *FAIL* commit message does not contain magic 'submodule' word
 remote: hooklet hooks/update.secondary.d/check-submodule-refs failed
 remote: hooks/update.secondary died
 remote: error: hook declined to update refs/heads/master
 To ssh://git@git.haskell.org/ghc.git
  ! [remote rejected] master -> master (hook declined)
 error: failed to push some refs to 'ssh://git@git.haskell.org/ghc.git'
 }}}

 2. Rewrite the commit message to include the magic word, and try pusing
 again:
 {{{
 $ git commit --amend -s -m "Update submodule to Win32-2.3.0.2"
 $ git push
 ...
 remote: performing tab-check...
 remote: performing submodule-ref update validations...
 remote: Submodule update(s) detected in
 a24ef02140dabb42dfbd2b649434017af6bb6fca:
 remote:  libraries/Win32 => c51e81a43cd5e9540453bd5ca6da8992245a4774
 remote: *FAIL* commit not found in submodule repo
 ('../packages/Win32.git')
 remote:        or not reachable from persistent branches
 remote: hooklet hooks/update.secondary.d/check-submodule-refs failed
 remote: hooks/update.secondary died
 remote: error: hook declined to update refs/heads/master
 To ssh://git@git.haskell.org/ghc.git
  ! [remote rejected] master -> master (hook declined)
 error: failed to push some refs to 'ssh://git@git.haskell.org/ghc.git'
 }}}

 3. Making sure the `Win32` sub-repo actually contains the new commit
 `ghc.git` is going to refer to, and try pushing again:
 {{{
 $ (cd libraries/Win32 ; git push origin HEAD:ghc-head)
 ...
 To ssh://git@git.haskell.org/packages/Win32.git
    1e909ad..c51e81a  ghc-head -> ghc-head

 $ git push
 ...
 remote: performing tab-check...
 remote: performing submodule-ref update validations...
 remote: Submodule update(s) detected in
 696bfc4ba5fce6b75cc91bcb67c5d0a3c9f29bd2:
 remote:  libraries/Win32 => c51e81a43cd5e9540453bd5ca6da8992245a4774
 remote:  OK
 remote: mirroring ssh://git@git.haskell.org/ghc to
 ssh://git@github.com/ghc/ghc ...
 remote: To ssh://git@github.com/ghc/ghc
 remote:    3099e40..696bfc4  master -> master
 remote: running notifier
 To ssh://git@git.haskell.org/ghc.git
    3099e40..696bfc4  master -> master
 }}}

 The last `git push` finally succeeded!

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8251#comment:5>
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