Re: [RFC/PATCH 1/3] tree.c: add support for traversal of submodules

[Junio C Hamano <gitster@pobox.com>]

Lars Hjemli <hjemli@gmail.com> writes:

> If the commit referenced by a gitlink is available in the (possibly
> alternate) object database, read_tree_recursive() is now able to descend
> into the tree of the linked commit if the flag 'traverse_gitlinks' is
> turned on.
>
> Signed-off-by: Lars Hjemli <hjemli@gmail.com>
> ---
>  tree.c |   20 +++++++++++++++++---
>  tree.h |    1 +
>  2 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/tree.c b/tree.c
> index 03e782a..1468e10 100644
> --- a/tree.c
> +++ b/tree.c
> @@ -7,6 +7,7 @@
>  #include "tree-walk.h"
>  
>  const char *tree_type = "tree";
> +int traverse_gitlinks = 0;

I think we tend to put these global settings that will affect everybody in
environment.c.  You do not have to initialize variable to zero; BSS will
take care of it.

When the user explicitly asks you to traverse into submodules and the
necessary commit is not available in a submodule, the code goes on without
complaining.  I am not saying it is bad, but I wonder if we would want to
distinguish these three cases:

 (1) the submodule is initialized and the necessary commit is there.

 (2) the submodule is initialized, but the necessary commit is missing.

 (3) the submodule is not even initialized (aka "the user is not
     interested in it"); there is only an empty directory.

I think it is perfectly fine not to say anything for (3) but I am unsure
about the second case.