[PATCH v2] submodule.h: use a named enum for RECURSE_SUBMODULES_*

From: Philippe Blain <levraiphilippeblain@gmail.com>

Using a named enum allows casting an integer to the enum type in both GDB and LLDB:

    $ gdb -q -ex 'b wt-status.c:44' -ex r --args ./git status
    (gdb) p (enum color_wt_status) slot
    $1 = WT_STATUS_ONBRANCH

    $ lldb -o 'b wt-status.c:44' -o r -- ./git status
    (lldb) p (color_wt_status) slot
    (color_wt_status) $0 = WT_STATUS_ONBRANCH

In LLDB, it's also required to cast in the reversed direction, i.e. cast an enum constant into its corresponding integer:

    (lldb) p (int) color_wt_status::WT_STATUS_ONBRANCH
    (int) $1 = 8

Name the enum listing the different RECURSE_SUBMODULES_* modes, to make debugging easier. For example, when stepping through a part of the code where an int is compared with a constant in this enum, it allows casting the int to the enum type or vice-versa, after quickly checking where the enum constant is declared and learning the enum name.

As to not make this patch a debug-only change, convert the 'fetch_recurse' member of 'struct submodule' to use the newly named enum.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
---
    submodule.h: use a named enum for RECURSE_SUBMODULES_*
    
    Changes since v1:
    
     * converted one user of the enum from an 'int' to the new enum type, so
       the patch is not debug-only, as suggested by Glen.
     * updated the commit message to use an 'int' as example of a local
       variable being compared with an enum constant, instead of using a
       struct member which is already of enum type, as pointed out by Junio
     * added a little bit more explanation in the commit message as to how
       this patch can help when debugging.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1111%2Fphil-blain%2Fsubmodule-recurse-enum-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1111/phil-blain/submodule-recurse-enum-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1111

Range-diff vs v1:

 1:  4c787d4054e ! 1:  e0b211b88f5 submodule.h: use a named enum for RECURSE_SUBMODULES_*
     @@ Commit message
          Using a named enum allows casting an integer to the enum type in both
          GDB and LLDB:
      
     -        (gdb) p (enum diff_submodule_format) options->submodule_format
     -        $1 = DIFF_SUBMODULE_LOG
     +        $ gdb -q -ex 'b wt-status.c:44' -ex r --args ./git status
     +        (gdb) p (enum color_wt_status) slot
     +        $1 = WT_STATUS_ONBRANCH
      
     -        (lldb) p (diff_submodule_format) options->submodule_format
     -        (diff_submodule_format) $1 = DIFF_SUBMODULE_LOG
     +        $ lldb -o 'b wt-status.c:44' -o r -- ./git status
     +        (lldb) p (color_wt_status) slot
     +        (color_wt_status) $0 = WT_STATUS_ONBRANCH
      
          In LLDB, it's also required to cast in the reversed direction, i.e.
          cast an enum constant into its corresponding integer:
      
     -        (lldb) p (int) diff_submodule_format::DIFF_SUBMODULE_SHORT
     -        (int) $0 = 0
     +        (lldb) p (int) color_wt_status::WT_STATUS_ONBRANCH
     +        (int) $1 = 8
      
          Name the enum listing the different RECURSE_SUBMODULES_* modes, to make
     -    debugging easier.
     +    debugging easier. For example, when stepping through a part of the code
     +    where an int is compared with a constant in this enum, it allows casting
     +    the int to the enum type or vice-versa, after quickly checking where the
     +    enum constant is declared and learning the enum name.
     +
     +    As to not make this patch a debug-only change, convert the
     +    'fetch_recurse' member of 'struct submodule' to use the newly named
     +    enum.
      
          Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
      
     + ## submodule-config.h ##
     +@@ submodule-config.h: struct submodule {
     + 	const char *path;
     + 	const char *name;
     + 	const char *url;
     +-	int fetch_recurse;
     ++	enum submodule_recurse_mode fetch_recurse;
     + 	const char *ignore;
     + 	const char *branch;
     + 	struct submodule_update_strategy update_strategy;
     +
       ## submodule.h ##
      @@ submodule.h: struct repository;
       struct string_list;

 submodule-config.h | 2 +-
 submodule.h        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)