Re: [PATCH 03/10] unpack-trees.[ch]: embed "dir" in "struct unpack_trees_options"

[Elijah Newren <newren@gmail.com>]

On Sun, Oct 3, 2021 at 5:46 PM Ævar Arnfjörð Bjarmason <avarab@gmail.com> wrote:
>
> Change the "struct dir" in "struct unpack_trees_options" away from a
> pointer to being embedded in the struct itself, this mean that we can
> initialize it with our new UNPACK_TREES_OPTIONS_INIT macro.
>
> As it turned out nothing actually needed to provide its own "struct
> dir" to this API, there's another patch to "hide" the struct instead,
> see the discussion at [1], but I think just allocating it on the stack
> along with the rest makes more sense.
>
> This fixes a memory leak in "builtin/checkout.c" that's been there
> since the clear_unpack_trees_porcelain() function was added in
> 1c41d2805e4 (unpack_trees_options: free messages when done,
> 2018-05-21), i.e. we still had a memory leak from allocating the "dir"
> member here. That "dir" member had in turn been with us ever since
> 782c2d65c24 (Build in checkout, 2008-02-07).
>
> This fixes that memory leak, and allows us to remove the boilerplate
> dir_clear() elsewhere in favor of just using
> clear_unpack_trees_porcelain().
>
> 1. https://lore.kernel.org/git/87ilyjviiy.fsf@evledraar.gmail.com/
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  builtin/checkout.c  |  5 ++---
>  builtin/read-tree.c | 11 ++++-------
>  merge-ort.c         |  7 ++-----
>  merge.c             |  7 ++-----
>  unpack-trees.c      | 10 ++++------
>  unpack-trees.h      |  4 +++-
>  6 files changed, 17 insertions(+), 27 deletions(-)
>
> diff --git a/builtin/checkout.c b/builtin/checkout.c
> index fea4533dbec..d4b88affba7 100644
> --- a/builtin/checkout.c
> +++ b/builtin/checkout.c
> @@ -745,9 +745,8 @@ static int merge_working_tree(const struct checkout_opts *opts,
>                                        &new_branch_info->commit->object.oid :
>                                        &new_branch_info->oid, NULL);
>                 if (opts->overwrite_ignore) {
> -                       topts.dir = xcalloc(1, sizeof(*topts.dir));
> -                       topts.dir->flags |= DIR_SHOW_IGNORED;
> -                       setup_standard_excludes(topts.dir);
> +                       topts.dir.flags |= DIR_SHOW_IGNORED;
> +                       setup_standard_excludes(&topts.dir);
>                 }
>                 tree = parse_tree_indirect(old_branch_info->commit ?
>                                            &old_branch_info->commit->object.oid :
> diff --git a/builtin/read-tree.c b/builtin/read-tree.c
> index 847182fdad6..06f3b97ac05 100644
> --- a/builtin/read-tree.c
> +++ b/builtin/read-tree.c
> @@ -53,20 +53,17 @@ static int index_output_cb(const struct option *opt, const char *arg,
>  static int exclude_per_directory_cb(const struct option *opt, const char *arg,
>                                     int unset)
>  {
> -       struct dir_struct *dir;
>         struct unpack_trees_options *opts;
>
>         BUG_ON_OPT_NEG(unset);
>
>         opts = (struct unpack_trees_options *)opt->value;
>
> -       if (opts->dir)
> +       if (opts->dir.exclude_per_dir)
>                 die("more than one --exclude-per-directory given.");
>
> -       dir = xcalloc(1, sizeof(*opts->dir));
> -       dir->flags |= DIR_SHOW_IGNORED;
> -       dir->exclude_per_dir = arg;
> -       opts->dir = dir;
> +       opts->dir.flags |= DIR_SHOW_IGNORED;
> +       opts->dir.exclude_per_dir = arg;
>         /* We do not need to nor want to do read-directory
>          * here; we are merely interested in reusing the
>          * per directory ignore stack mechanism.
> @@ -208,7 +205,7 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
>         if ((opts.update || opts.index_only) && !opts.merge)
>                 die("%s is meaningless without -m, --reset, or --prefix",
>                     opts.update ? "-u" : "-i");
> -       if ((opts.dir && !opts.update))
> +       if ((opts.dir.exclude_per_dir && !opts.update))
>                 die("--exclude-per-directory is meaningless unless -u");
>         if (opts.merge && !opts.index_only)
>                 setup_work_tree();
> diff --git a/merge-ort.c b/merge-ort.c
> index 75d2b8e4b99..e526b78b88d 100644
> --- a/merge-ort.c
> +++ b/merge-ort.c
> @@ -4045,9 +4045,8 @@ static int checkout(struct merge_options *opt,
>         unpack_opts.verbose_update = (opt->verbosity > 2);
>         unpack_opts.fn = twoway_merge;
>         if (1/* FIXME: opts->overwrite_ignore*/) {
> -               CALLOC_ARRAY(unpack_opts.dir, 1);
> -               unpack_opts.dir->flags |= DIR_SHOW_IGNORED;
> -               setup_standard_excludes(unpack_opts.dir);
> +               unpack_opts.dir.flags |= DIR_SHOW_IGNORED;
> +               setup_standard_excludes(&unpack_opts.dir);
>         }
>         parse_tree(prev);
>         init_tree_desc(&trees[0], prev->buffer, prev->size);
> @@ -4056,8 +4055,6 @@ static int checkout(struct merge_options *opt,
>
>         ret = unpack_trees(2, trees, &unpack_opts);
>         clear_unpack_trees_porcelain(&unpack_opts);
> -       dir_clear(unpack_opts.dir);
> -       FREE_AND_NULL(unpack_opts.dir);
>         return ret;
>  }
>
> diff --git a/merge.c b/merge.c
> index 086f04b0f97..9cb32990dd9 100644
> --- a/merge.c
> +++ b/merge.c
> @@ -53,7 +53,6 @@ int checkout_fast_forward(struct repository *r,
>         struct unpack_trees_options opts = UNPACK_TREES_OPTIONS_INIT;
>         struct tree_desc t[MAX_UNPACK_TREES];
>         int i, nr_trees = 0;
> -       struct dir_struct dir = DIR_INIT;
>         struct lock_file lock_file = LOCK_INIT;
>
>         refresh_index(r->index, REFRESH_QUIET, NULL, NULL, NULL);
> @@ -80,9 +79,8 @@ int checkout_fast_forward(struct repository *r,
>         }
>
>         if (overwrite_ignore) {
> -               dir.flags |= DIR_SHOW_IGNORED;
> -               setup_standard_excludes(&dir);
> -               opts.dir = &dir;
> +               opts.dir.flags |= DIR_SHOW_IGNORED;
> +               setup_standard_excludes(&opts.dir);
>         }
>
>         opts.head_idx = 1;
> @@ -100,7 +98,6 @@ int checkout_fast_forward(struct repository *r,
>                 clear_unpack_trees_porcelain(&opts);
>                 return -1;
>         }
> -       dir_clear(&dir);
>         clear_unpack_trees_porcelain(&opts);
>
>         if (write_locked_index(r->index, &lock_file, COMMIT_LOCK))
> diff --git a/unpack-trees.c b/unpack-trees.c
> index 393c1f35a5d..94767d3f96f 100644
> --- a/unpack-trees.c
> +++ b/unpack-trees.c
> @@ -196,6 +196,7 @@ void unpack_trees_options_init(struct unpack_trees_options *o)
>  void clear_unpack_trees_porcelain(struct unpack_trees_options *opts)
>  {
>         strvec_clear(&opts->msgs_to_free);
> +       dir_clear(&opts->dir);
>         memset(opts->msgs, 0, sizeof(opts->msgs));
>  }
>
> @@ -2085,7 +2086,7 @@ static int verify_clean_subdirectory(const struct cache_entry *ce,
>          */
>         int namelen;
>         int i;
> -       struct dir_struct d;
> +       struct dir_struct d = DIR_INIT;
>         char *pathbuf;
>         int cnt = 0;
>
> @@ -2136,9 +2137,7 @@ static int verify_clean_subdirectory(const struct cache_entry *ce,
>          */
>         pathbuf = xstrfmt("%.*s/", namelen, ce->name);
>
> -       memset(&d, 0, sizeof(d));
> -       if (o->dir)
> -               d.exclude_per_dir = o->dir->exclude_per_dir;
> +       d.exclude_per_dir = o->dir.exclude_per_dir;
>         i = read_directory(&d, o->src_index, pathbuf, namelen+1, NULL);
>         if (i)
>                 return add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
> @@ -2179,8 +2178,7 @@ static int check_ok_to_remove(const char *name, int len, int dtype,
>         if (ignore_case && icase_exists(o, name, len, st))
>                 return 0;
>
> -       if (o->dir &&
> -           is_excluded(o->dir, o->src_index, name, &dtype))
> +       if (is_excluded(&o->dir, o->src_index, name, &dtype))
>                 /*
>                  * ce->name is explicitly excluded, so it is Ok to
>                  * overwrite it.
> diff --git a/unpack-trees.h b/unpack-trees.h
> index 892b65ea623..40c4841748d 100644
> --- a/unpack-trees.h
> +++ b/unpack-trees.h
> @@ -5,6 +5,7 @@
>  #include "strvec.h"
>  #include "string-list.h"
>  #include "tree-walk.h"
> +#include "dir.h"
>
>  #define MAX_UNPACK_TREES MAX_TRAVERSE_TREES
>
> @@ -66,7 +67,7 @@ struct unpack_trees_options {
>                      dry_run;
>         const char *prefix;
>         int cache_bottom;
> -       struct dir_struct *dir;
> +       struct dir_struct dir;
>         struct pathspec *pathspec;
>         merge_fn_t fn;
>         const char *msgs[NB_UNPACK_TREES_WARNING_TYPES];
> @@ -93,6 +94,7 @@ struct unpack_trees_options {
>
>  #define UNPACK_TREES_OPTIONS_INIT { \
>         .msgs_to_free = STRVEC_INIT, \
> +       .dir = DIR_INIT, \
>  }
>  void unpack_trees_options_init(struct unpack_trees_options *o);
>
> --
> 2.33.0.1404.g83021034c5d

This patch is going to conflict HEAVILY with
en/removing-untracked-fixes, which Junio already said he'd merge to
next.

You should rebase your patches on that series.