Documentation/notes: clean up description of rewriting configuration

diff --git a/git-submodule.sh b/git-submodule.sh
index 664f21721cb876eed7da167744066d834521c825..2dd372a21d82a109774e80e014f9959485202b3e 100755 (executable)
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -222,7 +222,7 @@ cmd_add()
 
                module_clone "$path" "$realrepo" "$reference" || exit
                (
-                       unset GIT_DIR
+                       clear_local_git_env
                        cd "$path" &&
                        # ash fails to wordsplit ${branch:+-b "$branch"...}
                        case "$branch" in
@@ -278,7 +278,7 @@ cmd_foreach()
                        name=$(module_name "$path")
                        (
                                prefix="$prefix$path/"
-                               unset GIT_DIR
+                               clear_local_git_env
                                cd "$path" &&
                                eval "$@" &&
                                if test -n "$recursive"
@@ -434,7 +434,7 @@ cmd_update()
                        module_clone "$path" "$url" "$reference"|| exit
                        subsha1=
                else
-                       subsha1=$(unset GIT_DIR; cd "$path" &&
+                       subsha1=$(clear_local_git_env; cd "$path" &&
                                git rev-parse --verify HEAD) ||
                        die "Unable to find current revision in submodule path '$path'"
                fi
@@ -454,7 +454,7 @@ cmd_update()
 
                        if test -z "$nofetch"
                        then
-                               (unset GIT_DIR; cd "$path" &&
+                               (clear_local_git_env; cd "$path" &&
                                        git-fetch) ||
                                die "Unable to fetch in submodule path '$path'"
                        fi
@@ -477,14 +477,14 @@ cmd_update()
                                ;;
                        esac
 
-                       (unset GIT_DIR; cd "$path" && $command "$sha1") ||
+                       (clear_local_git_env; cd "$path" && $command "$sha1") ||
                        die "Unable to $action '$sha1' in submodule path '$path'"
                        say "Submodule path '$path': $msg '$sha1'"
                fi
 
                if test -n "$recursive"
                then
-                       (unset GIT_DIR; cd "$path" && cmd_update $orig_args) ||
+                       (clear_local_git_env; cd "$path" && cmd_update $orig_args) ||
                        die "Failed to recurse into submodule path '$path'"
                fi
        done
@@ -492,7 +492,7 @@ cmd_update()
 
 set_name_rev () {
        revname=$( (
-               unset GIT_DIR
+               clear_local_git_env
                cd "$1" && {
                        git describe "$2" 2>/dev/null ||
                        git describe --tags "$2" 2>/dev/null ||
@@ -553,12 +553,17 @@ cmd_summary() {
 
        test $summary_limit = 0 && return
 
-       if rev=$(git rev-parse -q --verify "$1^0")
+       if rev=$(git rev-parse -q --verify --default HEAD ${1+"$1"})
        then
                head=$rev
-               shift
+               test $# = 0 || shift
+       elif test -z "$1" -o "$1" = "HEAD"
+       then
+               # before the first commit: compare with an empty tree
+               head=$(git hash-object -w -t tree --stdin </dev/null)
+               test -z "$1" || shift
        else
-               head=HEAD
+               head="HEAD"
        fi
 
        if [ -n "$files" ]
@@ -757,7 +762,7 @@ cmd_status()
                else
                        if test -z "$cached"
                        then
-                               sha1=$(unset GIT_DIR; cd "$path" && git rev-parse --verify HEAD)
+                               sha1=$(clear_local_git_env; cd "$path" && git rev-parse --verify HEAD)
                                set_name_rev "$path" "$sha1"
                        fi
                        say "+$sha1 $displaypath$revname"
@@ -767,7 +772,7 @@ cmd_status()
                then
                        (
                                prefix="$displaypath/"
-                               unset GIT_DIR
+                               clear_local_git_env
                                cd "$path" &&
                                cmd_status $orig_args
                        ) ||
@@ -818,7 +823,7 @@ cmd_sync()
                if test -e "$path"/.git
                then
                (
-                       unset GIT_DIR
+                       clear_local_git_env
                        cd "$path"
                        remote=$(get_default_remote)
                        say "Synchronizing submodule url for '$name'"