Re: [RFC PATCH 11/13] walken: add filtered object walk

[Jeff Hostetler <git@jeffhostetler.com>]

On 6/6/2019 9:08 PM, Emily Shaffer wrote:
> Demonstrate how filter specs can be used when performing a revision walk
> of all object types. In this case, tree depth is used. Contributors who
> are following the revision walking tutorial will be encouraged to run
> the revision walk with and without the filter in order to compare the
> number of objects seen in each case.
> 
> Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
> ---
>   builtin/walken.c | 18 +++++++++++++++++-
>   1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/builtin/walken.c b/builtin/walken.c
> index 408af6c841..f2c98bcd6b 100644
> --- a/builtin/walken.c
> +++ b/builtin/walken.c
> @@ -13,6 +13,7 @@
>   #include "pretty.h"
>   #include "line-log.h"
>   #include "list-objects.h"
> +#include "list-objects-filter-options.h"
>   #include "grep.h"
>   
>   static const char * const walken_usage[] = {
> @@ -154,7 +155,22 @@ static int walken_object_walk(struct rev_info *rev)
>   	blob_count = 0;
>   	tree_count = 0;
>   
> -	traverse_commit_list(rev, walken_show_commit, walken_show_object, NULL);
> +	if (1) {
> +		/* Unfiltered: */
> +		printf(_("Unfiltered object walk.\n"));
> +		traverse_commit_list(rev, walken_show_commit,
> +				walken_show_object, NULL);
> +	} else {
> +		printf(_("Filtered object walk with filterspec 'tree:1'.\n"));
> +		/*
> +		 * We can parse a tree depth of 1 to demonstrate the kind of
> +		 * filtering that could occur eg during shallow cloning.
> +		 */

I think I'd avoid the term "shallow clone" here.  Shallow clone
refers to getting a limited commit history.  That's orthogonal from
partial clone and the filtered tree walk that operates *within* a commit
or a series of commits.

Granted, a user might want to do both a shallow and partial clone (and
then later partial fetches), but I wouldn't mix the concepts here.


> +		parse_list_objects_filter(&filter_options, "tree:1");
> +
> +		traverse_commit_list_filtered(&filter_options, rev,
> +			walken_show_commit, walken_show_object, NULL, &omitted);
> +	}
>   
>   	printf(_("Object walk completed. Found %d commits, %d blobs, %d tags, "
>   	       "and %d trees.\n"), commit_count, blob_count, tag_count,
>