Refactor checking for (type of) Git repository

lib now has two new functions:

is_git_repo returns 0/true if its argument is a git repository
get_git_repo_type return 0/true if its argument is a git repository and
  prints one of non-bare/bare/fake-bare to stdout

The mr function implementations now use these functions and have been
simplified. We also allow bare repositories with limited functionality.

diff --git a/mr b/mr
index b26802738f284d84e53c7f0d3536e488e11dc2cd..c646a3bbbcc2b49c8f06e579285dc80648a2d7b1 100755 (executable)
--- a/mr
+++ b/mr
@@ -956,19 +956,41 @@ lib =
                        exit 1
                fi
        }
+       get_git_repo_type()
+       {
+               if [ -d "$1"/.git ] && [ -d "$1"/.git/refs/heads ] &&
+                       [ -d "$1"/.git/objects ] && [ -f "$1"/.git/config ];
+                       then
+                       echo non-bare
+               elif [ -d "$1"/refs/heads ] && [ -d "$1"/refs/tags ] &&
+                       [ -d "$1"/objects ] && [ -f "$1"/config ]; then
+                       local bare
+                       bare="$(GIT_CONFIG="$1"/config git-config --get core.bare)"
+                       case "$bare" in
+                               true) echo bare;;
+                               false) echo fake-bare;;
+                               *) return 255;;
+                       esac
+               else
+                       return 1
+               fi
+       }
+       is_git_repo() {
+               get_git_repo_type "$1" >/dev/null
+       }
 
 update =
        if [ -d "$MR_REPO"/.svn ]; then
                svn update "$@"
-       elif [ -d "$MR_REPO"/.git ] || [ "${MR_REPO%.git/}" != "$MR_REPO" ]; then
-               # this is a bug in git-fetch, which requires GIT_DIR set
-               [ "${MR_REPO%.git/}" != "$MR_REPO" ] && GIT_DIR="$MR_REPO" && export GIT_DIR
-               if [ -z "$@" ]; then
-                       git pull -t origin master
-               else
-                       git pull "$@"
-               fi
-               unset GIT_DIR
+       elif is_git_repo "$MR_REPO"; then
+               # all this is because of a bug in git-fetch, which requires GIT_DIR set
+               local git_dir_override; git_dir_override=.git
+               case "$(get_git_repo_type "$MR_REPO")" in
+                       fake-bare) git_dir_override="$MR_REPO";;
+               esac
+               args="$@"
+               [ -z "$args" ] && args="-t origin master"
+               eval GIT_DIR="$git_dir_override" git pull "$args"
        elif [ -d "$MR_REPO"/.bzr ]; then
                bzr merge "$@"
        elif [ -d "$MR_REPO"/CVS ]; then
@@ -983,7 +1005,7 @@ update =
 status =
        if [ -d "$MR_REPO"/.svn ]; then
                svn status "$@"
-       elif [ -d "$MR_REPO"/.git ] || [ "${MR_REPO%.git/}" != "$MR_REPO" ]; then
+       elif is_git_repo "$MR_REPO"; then
                git status "$@" || true
        elif [ -d "$MR_REPO"/.bzr ]; then
                bzr status "$@"
@@ -999,10 +1021,12 @@ status =
 commit =
        if [ -d "$MR_REPO"/.svn ]; then
                svn commit "$@"
-       elif [ -d "$MR_REPO"/.git ]; then
+       elif is_git_repo "$MR_REPO"; then
+               case "$(get_git_repo_type "$MR_REPO")" in
+                       bare) error "cannot commit to bare git repositories";;
+                       fake-bare) error "commit does not work for fake bare git repositories (yet).";;
+               esac
                git commit -a "$@" && git push --all
-       elif [ "${MR_REPO%.git/}" != "$MR_REPO" ]; then
-               error "commit does not work for fake bare git repositories (yet)."
        elif [ -d "$MR_REPO"/.bzr ]; then
                bzr commit "$@" && bzr push
        elif [ -d "$MR_REPO"/CVS ]; then
@@ -1017,10 +1041,12 @@ commit =
 diff =
        if [ -d "$MR_REPO"/.svn ]; then
                svn diff "$@"
-       elif [ -d "$MR_REPO"/.git ]; then
+       elif is_git_repo "$MR_REPO"; then
+               case "$(get_git_repo_type "$MR_REPO")" in
+                       bare) error "cannot diff in bare git repositories";;
+                       fake-bare) error "diff does not work for fake bare git repositories (yet).";;
+               esac
                git diff "$@"
-       elif [ "${MR_REPO%.git/}" != "$MR_REPO" ]; then
-               error "commit does not work for fake bare git repositories (yet)."
        elif [ -d "$MR_REPO"/.bzr ]; then
                bzr diff "$@"
        elif [ -d "$MR_REPO"/CVS ]; then
@@ -1035,7 +1061,7 @@ diff =
 log =
        if [ -d "$MR_REPO"/.svn ]; then
                svn log"$@"
-       elif [ -d "$MR_REPO"/.git ] || [ "${MR_REPO%.git/}" != "$MR_REPO" ]; then
+       elif is_git_repo "$MR_REPO"; then
                git log "$@"
        elif [ -d "$MR_REPO"/.bzr ]; then
                bzr log "$@"
@@ -1060,37 +1086,33 @@ register =
                fi
                echo "Registering svn url: $url in $MR_CONFIG"
                mr -c "$MR_CONFIG" config "$(pwd)" checkout="svn co $url $basedir"
-       elif [ -d .git ] || [ "${basedir%.git}" != "$basedir" ]; then
-               GIT_CONFIG=.git/config
-               [ ! -f $GIT_CONFIG ] && GIT_CONFIG=config
-               export GIT_CONFIG
-               url="$(LANG=C git-config --get remote.origin.url)"
+       elif is_git_repo .; then
+               local repo_type; repo_type="$(get_git_repo_type .)"
+               local config;
+               case "$repo_type" in
+                       non-bare) config=.git/config;;
+                       bare|fake-bare) config=config;;
+                       *) error "unknown git repository type: $repo_type"
+               esac
+               url="$(LANG=C GIT_CONFIG="$config" git-config --get remote.origin.url)"
                if [ -z "$url" ]; then
                        error "cannot determine git url"
                fi
-               if [ $GIT_CONFIG = config ]; then
-                       # this seems like a bare repo as it has no worktree.
-                       # mr needs a worktree and cannot work with bare
-                       # repositories, so ensure that it's "fake bare" and
-                       # has a worktree configured.
-                       case "$(git-config --get core.bare)" in
-                               true) error "cannot register a bare git repository";;
-                       esac
-                       GIT_WORK_TREE="$(git-config --get core.worktree)" || :
-                       case "$GIT_WORK_TREE" in
-                               '') error "cannot register a fake bare git repository without core.worktree";;
-                               *)
-                                       if [ ! -d "$GIT_WORK_TREE" ]; then
-                                               error "git worktree $GIT_WORK_TREE does not exist"
-                                       fi;;
-                       esac
-                       suffix=" (with worktree $GIT_WORK_TREE)"
-                       mr -c "$MR_CONFIG" config "$(pwd)" \
-                               lib="GIT_WORK_TREE=$GIT_WORK_TREE; export GIT_WORK_TREE"
-                       unset GIT_WORK_TREE
-               fi
+               case "$repo_type" in
+                       bare|fake-bare)
+                               # this seems like a bare repo as it has no
+                               # worktree.
+                               local work_tree
+                               work_tree="$(git-config --get core.worktree)" || :
+                               if [ ! -d "$work_tree" ]; then
+                                       error "git worktree $work_tree does not exist"
+                               fi
+                               suffix=" (with worktree $work_tree)"
+                               mr -c "$MR_CONFIG" config "$(pwd)" \
+                                       lib="GIT_WORK_TREE=$work_tree; export GIT_WORK_TREE"
+                               ;;
+               esac
                echo "Registering git url: $url in $MR_CONFIG${suffix:-}"
-               unset GIT_CONFIG
                mr -c "$MR_CONFIG" config "$(pwd)" checkout="git clone $url $basedir"
        elif [ -d .bzr ]; then
                url=$(cat .bzr/branch/parent)