git - submodule helpers

Below are some git commands which can be useful to resolve problems with submodules.

Get a list of commits inside a submodule

Submodules are identified by SHA-1 hashes so you may need to get a list of them. Do the following inside the submodule folder (or inside the separate submodule repository):


  $ git log --oneline

  5bd722f commit 5
  b5c1524 commit 4
  2444bfa commit 3
  e0eadd5 commit 2
  c180c5a commit 1
  702fc8a commit 0

View current submodule commit


  $ git submodule status
  
  5bd722fa26dcdd64128392aa28e08849fe37f111 sub (heads/master)

Compare a submodule state with another branch

Assume we are on the "branch1" and want to compare 'sub' submodule state with master:


  $ git diff master -- sub
  
  diff --git a/sub b/sub
  index 702fc8a..5bd722f 160000
  --- a/sub
  +++ b/sub
  @@ -1 +1 @@
  -Subproject commit 702fc8a7edcdf5ceba9929958bd6cd7f000eb369
  +Subproject commit 5bd722fa26dcdd64128392aa28e08849fe37f111

Where "-Subproject commit" is another (master) branch state and "+Subproject commit" is a current branch state.

View changes to submodule state on the current branch

What we do is show a git log with diffs for submodule (named 'sub' in this case):


  $ git log -p sub
  
  commit 261aa4bdb6944c77fc98e52748d656e56969ba6a
  Author: name
  Date:   Thu Sep 13 15:20:48 2012 +0300
  accidental sub switch to commit 5
  diff --git a/sub b/sub
  index b5c1524..5bd722f 160000
  --- a/sub
  +++ b/sub
  @@ -1 +1 @@
  -Subproject commit b5c15241fe40f122d5225e5c76457802de3ad605
  +Subproject commit 5bd722fa26dcdd64128392aa28e08849fe37f111

  commit 073aaf160706d705c6c95ab21327388cd6683486
  Author: name
  Date:   Thu Sep 13 14:58:41 2012 +0300
  sub commit 4
  diff --git a/sub b/sub
  index 2444bfa..b5c1524 160000
  --- a/sub
  +++ b/sub
  @@ -1 +1 @@
  -Subproject commit 2444bfa760b5d3cc974658bd18482f9679f52b69
  +Subproject commit b5c15241fe40f122d5225e5c76457802de3ad605

   ...

Where "-Subproject commit" is a previous submodule state and "+Subproject commit" is a new submodule state.