[BUG] Hang when I did something a bit weird with submodules

Hi,

I was just setting up a new project using submodules and have run into what appears to be a hang when git status is invoked. I haven't tried to reproduce this but this is basically what I did (edited highlights from my bash_history).

 $ git --version
 git version 2.0.3
 $ mkdir proj
 $ cd proj
 $ git init
 $ git submodule add <internal-repo-with-build-scripts> build
 $ git submodule add --reference ~/src/linux/.git
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux
 # I'm not sure if the --reference is relevant but I was just wanting
to cut down on my network transfer
 $ git submodule add <internal-repo-with-skeleton-fs> rootfs

Oops I really wanted linux-stable to get the same version my board vendor is using

 $ vim .gitmodules
 # change to linux-stable
 $ git submodule sync

I'm not sure if this is a valid use-case but nothing complained that I was changing the URL. In theory linux-stable should be a super-set of linus' tree so the repositories are basically equivalent.

 $ cd linux/
 $ git remote show origin
 * remote origin
   Fetch URL: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
 # Seems to have done the trick
 $ git reset --hard v3.4.69

I suspect this is where the problem starts. When I did the git submodule add it was pointing at the tip of linus' tree. Now I have rewound considerably.

 $ git status
 [hang]

For what it's worth here's the output when I run with GIT_TRACE=1 git status

trace: built-in: git 'status' trace: run_command: 'status' '--porcelain' trace: exec: 'git' 'status' '--porcelain' trace: built-in: git 'status' '--porcelain' trace: run_command: 'status' '--porcelain' trace: exec: 'git' 'status' '--porcelain' trace: built-in: git 'status' '--porcelain' trace: run_command: 'status' '--porcelain' trace: exec: 'git' 'status' '--porcelain' trace: built-in: git 'status' '--porcelain' On branch master

Initial commit

Changes to be committed:
  (use "git rm --cached <file>..." to unstage)

        new file:   .gitmodules
        new file:   rootfs
        new file:   build
        new file:   linux

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

        modified:   .gitmodules
        modified:   linux (new commits)

trace: run_command: 'submodule' 'summary' '--cached' '--for-status' '--summary-limit' '-1' 'HEAD' trace: exec: 'git' 'submodule' 'summary' '--cached' '--for-status' '--summary-limit' '-1' 'HEAD' trace: exec: 'git-submodule' 'summary' '--cached' '--for-status' '--summary-limit' '-1' 'HEAD' trace: run_command: 'git-submodule' 'summary' '--cached' '--for-status' '--summary-limit' '-1' 'HEAD' trace: built-in: git 'rev-parse' '--git-dir' trace: built-in: git 'rev-parse' '-q' '--git-dir' trace: built-in: git 'rev-parse' '--show-prefix' trace: built-in: git 'rev-parse' '--show-toplevel' trace: built-in: git 'rev-parse' '-q' '--verify' '--default' 'HEAD' 'HEAD' trace: built-in: git 'hash-object' '-w' '-t' 'tree' '--stdin' trace: built-in: git 'rev-parse' '--show-toplevel' trace: built-in: git 'rev-parse' '--sq' '--prefix' '' '--' trace: built-in: git 'diff-index' '--cached' '--ignore-submodules=dirty' '--raw' '4b825dc642cb6eb9a060e54bf8d69288fbee4904' '--' trace: built-in: git 'config' '-f' '.gitmodules' '--get-regexp' '^submodule\..*\.path$' trace: built-in: git 'config' 'submodule.rootfs.ignore' trace: built-in: git 'config' '-f' '.gitmodules' 'submodule.rootfs.ignore' trace: built-in: git 'config' '-f' '.gitmodules' '--get-regexp' '^submodule\..*\.path$' trace: built-in: git 'config' 'submodule.build.ignore' trace: built-in: git 'config' '-f' '.gitmodules' 'submodule.build.ignore' trace: built-in: git 'config' '-f' '.gitmodules' '--get-regexp' '^submodule\..*\.path$' trace: built-in: git 'config' 'submodule.linux.ignore' trace: built-in: git 'config' '-f' '.gitmodules' 'submodule.linux.ignore' trace: built-in: git 'diff-index' '--cached' '--ignore-submodules=dirty' '--raw' '4b825dc642cb6eb9a060e54bf8d69288fbee4904' '--' 'rootfs' 'build' 'linux' trace: built-in: git 'rev-parse' '-q' '--verify' 'e4bbdf3b45828a2e9ca37ef329b8e708e324dfb1^0' trace: built-in: git 'rev-list' '--first-parent' 'e4bbdf3b45828a2e9ca37ef329b8e708e324dfb1' '--' trace: built-in: git 'log' '--pretty=format: > %s' '-1' 'e4bbdf3b45828a2e9ca37ef329b8e708e324dfb1' trace: built-in: git 'rev-parse' '-q' '--verify' '9f2d1659df78ea51eaa9ad5e7af9271996ac2a4c^0' trace: built-in: git 'rev-list' '--first-parent' '9f2d1659df78ea51eaa9ad5e7af9271996ac2a4c' '--' trace: built-in: git 'log' '--pretty=format: > %s' '-1' '9f2d1659df78ea51eaa9ad5e7af9271996ac2a4c' trace: built-in: git 'rev-parse' '-q' '--verify' '7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9^0' trace: built-in: git 'rev-list' '--first-parent' '7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9' '--' trace: built-in: git 'log' '--pretty=format: > %s' '-1' '7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9' Submodule changes to be committed:

* rootfs 0000000...e4bbdf3 (249):
  > Merge remote-tracking branch 'tomahawk/delivery_545_icmp'

* build 0000000...9f2d165 (771):
  > Merge remote-tracking branch 'plusplus/3rdparty'

* linux 0000000...7d1311b (46122):
  > Linux 3.17-rc1

trace: run_command: 'submodule' 'summary' '--files' '--for-status' '--summary-limit' '-1' trace: exec: 'git' 'submodule' 'summary' '--files' '--for-status' '--summary-limit' '-1' trace: exec: 'git-submodule' 'summary' '--files' '--for-status' '--summary-limit' '-1' trace: run_command: 'git-submodule' 'summary' '--files' '--for-status' '--summary-limit' '-1' trace: built-in: git 'rev-parse' '--git-dir' trace: built-in: git 'rev-parse' '-q' '--git-dir' trace: built-in: git 'rev-parse' '--show-prefix' trace: built-in: git 'rev-parse' '--show-toplevel' trace: built-in: git 'rev-parse' '-q' '--verify' '--default' 'HEAD' trace: built-in: git 'hash-object' '-w' '-t' 'tree' '--stdin' trace: built-in: git 'rev-parse' '--show-toplevel' trace: built-in: git 'rev-parse' '--sq' '--prefix' '' '--' trace: built-in: git 'diff-files' '--ignore-submodules=dirty' '--raw' '--' trace: built-in: git 'config' '-f' '.gitmodules' '--get-regexp' '^submodule\..*\.path$' trace: built-in: git 'config' 'submodule.linux.ignore' trace: built-in: git 'config' '-f' '.gitmodules' 'submodule.linux.ignore' trace: built-in: git 'diff-files' '--ignore-submodules=dirty' '--raw' '--' 'linux' trace: built-in: git 'rev-parse' 'HEAD' trace: built-in: git 'rev-parse' '-q' '--verify' '7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9^0' trace: built-in: git 'rev-parse' '-q' '--verify' '14aa272fcd1cdbe7173073250c767bc7a37278ce^0' trace: built-in: git 'rev-list' '--first-parent' '7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9...14aa272fcd1cdbe7173073250c767bc7a37278ce' '--' trace: built-in: git 'log' '--pretty=format: %m %s' '--first-parent' '7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9...14aa272fcd1cdbe7173073250c767bc7a37278ce' ^C