git-submodule.sh: 'checkout' is a valid update mode

'checkout' is documented as one of the valid values for the
'submodule.<name>.update' variable, and in a repository with the
variable set to 'checkout', "git submodule update" command does
update using the 'checkout' mode.

However, it has been an accident that the implementation works this
way; any unknown value would trigger the same codepath and update
using the 'checkout' mode.

Explicitly list 'checkout' as one of the known update modes, and
error out when an unknown update mode is used.

Teach the codepath that initializes the configuration variable from
an in-tree .gitmodules that 'checkout' is one of the valid values.
The code since ac1fbbda (submodule: do not copy unknown update mode
from .gitmodules, 2013-12-02) used to treat the value 'checkout' as
unknown and mapped it to 'none', which made little sense.  With this
change, 'checkout' specified in .gitmodules will stay to be 'checkout'.

Signed-off-by: Francesco Pretto <ceztko@gmail.com>
Signed-off-by: Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-submodule.sh b/git-submodule.sh
index 66f5f752c5fb6745ab409199deb775c4704ab3e6..5247f78f35455036a17914623d531e02a5fb617d 100755 (executable)
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -617,7 +617,7 @@ cmd_init()
                   test -z "$(git config submodule."$name".update)"
                then
                        case "$upd" in
-                       rebase | merge | none)
+                       checkout | rebase | merge | none)
                                ;; # known modes of updating
                        *)
                                echo >&2 "warning: unknown update mode '$upd' suggested for submodule '$name'"
@@ -803,6 +803,17 @@ cmd_update()
                        update_module=$update
                else
                        update_module=$(git config submodule."$name".update)
+                       case "$update_module" in
+                       '')
+                               ;; # Unset update mode
+                       checkout | rebase | merge | none)
+                               ;; # Known update modes
+                       !*)
+                               ;; # Custom update command
+                       *)
+                               die "$(eval_gettext "Invalid update mode '$update_module' for submodule '$name'")"
+                               ;;
+                       esac
                fi
 
                displaypath=$(relative_path "$prefix$sm_path")