Re: [PATCH 3/6] sparse-checkout: enable `set` to initialize sparse-checkout mode

On Tue, Dec 7, 2021 at 8:43 AM Derrick Stolee [off-list ref] wrote:

On 12/4/2021 3:00 PM, Elijah Newren via GitGitGadget wrote:

quoted

 static int sparse_checkout_set(int argc, const char **argv, const char *prefix)
 {
+     int mode, record_mode;
+     const char *default_patterns[] = {"/*", "!/*/"};

My gut reaction is that this array should be NULL terminated.

Sure, I can make that change.

quoted

+
      static struct option builtin_sparse_checkout_set_options[] = {
+             OPT_BOOL(0, "cone", &set_opts.cone_mode,
+                      N_("initialize the sparse-checkout in cone mode")),
+             OPT_BOOL(0, "sparse-index", &set_opts.sparse_index,
+                      N_("toggle the use of a sparse index")),
              OPT_BOOL(0, "stdin", &set_opts.use_stdin,
                       N_("read patterns from standard in")),
              OPT_END(),

@@ -700,11 +709,52 @@ static int sparse_checkout_set(int argc, const char **argv, const char *prefix)

      repo_read_index(the_repository);

+     set_opts.cone_mode = -1;
+     set_opts.sparse_index = -1;
+
      argc = parse_options(argc, argv, prefix,
                           builtin_sparse_checkout_set_options,
                           builtin_sparse_checkout_set_usage,
                           PARSE_OPT_KEEP_UNKNOWN);

+     /* Determine if we need to record the mode; ensure sparse checkout on */
+     record_mode = (set_opts.cone_mode != -1) || !core_apply_sparse_checkout;
+     core_apply_sparse_checkout = 1;
+
+     /* If not specified, use previous definition of cone mode */
+     if (set_opts.cone_mode == -1 && core_apply_sparse_checkout)
+             set_opts.cone_mode = core_sparse_checkout_cone;
+
+     /* Set cone/non-cone mode appropriately */
+     if (set_opts.cone_mode == 1) {
+             mode = MODE_CONE_PATTERNS;
+             core_sparse_checkout_cone = 1;
+     } else {
+             mode = MODE_ALL_PATTERNS;
+     }
+     if (record_mode && set_config(mode))
+             return 1;

I think it is appropriate to still have the init steps before the modification
of the worktree. I did have a brief pause to think about whether the set_config()
should be delayed until modify_pattern_list() succeeds.

quoted

+     /* Set sparse-index/non-sparse-index mode if specified */
+     if (set_opts.sparse_index >= 0) {
+             if (set_sparse_index_config(the_repository, set_opts.sparse_index) < 0)
+                     die(_("failed to modify sparse-index config"));
+
+             /* force an index rewrite */
+             repo_read_index(the_repository);
+             the_repository->index->updated_workdir = 1;
+     }
+
+     /*
+      * Cone mode automatically specifies the toplevel directory.  For
+      * non-cone mode, if nothing is specified, manually select just the
+      * top-level directory (much as 'init' would do).
+      */
+     if (!core_sparse_checkout_cone && argc == 0) {
+             argv = default_patterns;
+             argc = 2;

Perhaps use 'default_patterns_nr' as a constant near the definition of
'default_patterns' so these numbers are not so far apart?

Sounds like a good idea; will do.

quoted

+     }
+
      return modify_pattern_list(argc, argv, set_opts.use_stdin, REPLACE);
 }

Thanks,
-Stolee