Re: [PATCH v3 04/11] unpack-trees: introduce preserve_ignored to unpack_trees_options

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Mon, Sep 27 2021, Elijah Newren via GitGitGadget wrote:

> From: Elijah Newren <newren@gmail.com>
>
> Currently, every caller of unpack_trees() that wants to ensure ignored
> files are overwritten by default needs to:
>    * allocate unpack_trees_options.dir
>    * flip the DIR_SHOW_IGNORED flag in unpack_trees_options.dir->flags
>    * call setup_standard_excludes
> AND then after the call to unpack_trees() needs to
>    * call dir_clear()
>    * deallocate unpack_trees_options.dir
> That's a fair amount of boilerplate, and every caller uses identical
> code.  Make this easier by instead introducing a new boolean value where
> the default value (0) does what we want so that new callers of
> unpack_trees() automatically get the appropriate behavior.  And move all
> the handling of unpack_trees_options.dir into unpack_trees() itself.
>
> While preserve_ignored = 0 is the behavior we feel is the appropriate
> default, we defer fixing commands to use the appropriate default until a
> later commit.  So, this commit introduces several locations where we
> manually set preserve_ignored=1.  This makes it clear where code paths
> were previously preserving ignored files when they should not have been;
> a future commit will flip these to instead use a value of 0 to get the
> behavior we want.
>
> Signed-off-by: Elijah Newren <newren@gmail.com>
> ---
>  builtin/am.c        |  3 +++
>  builtin/checkout.c  | 11 ++---------
>  builtin/clone.c     |  2 ++
>  builtin/merge.c     |  2 ++
>  builtin/read-tree.c | 13 +++----------
>  builtin/reset.c     |  2 ++
>  builtin/stash.c     |  3 +++
>  merge-ort.c         |  8 +-------
>  merge-recursive.c   |  8 +-------
>  merge.c             |  8 +-------
>  reset.c             |  2 ++
>  sequencer.c         |  2 ++
>  unpack-trees.c      | 10 ++++++++++
>  unpack-trees.h      |  1 +
>  14 files changed, 35 insertions(+), 40 deletions(-)
>
> diff --git a/builtin/am.c b/builtin/am.c
> index e4a0ff9cd7c..1ee70692bc3 100644
> --- a/builtin/am.c
> +++ b/builtin/am.c
> @@ -1918,6 +1918,9 @@ static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
>  	opts.update = 1;
>  	opts.merge = 1;
>  	opts.reset = reset;
> +	if (!reset)
> +		/* FIXME: Default should be to remove ignored files */
> +		opts.preserve_ignored = 1;
>  	opts.fn = twoway_merge;
>  	init_tree_desc(&t[0], head->buffer, head->size);
>  	init_tree_desc(&t[1], remote->buffer, remote->size);
> diff --git a/builtin/checkout.c b/builtin/checkout.c
> index 5335435d616..5e7957dd068 100644
> --- a/builtin/checkout.c
> +++ b/builtin/checkout.c
> @@ -648,6 +648,7 @@ static int reset_tree(struct tree *tree, const struct checkout_opts *o,
>  	opts.skip_unmerged = !worktree;
>  	opts.reset = 1;
>  	opts.merge = 1;
> +	opts.preserve_ignored = 0;
>  	opts.fn = oneway_merge;
>  	opts.verbose_update = o->show_progress;
>  	opts.src_index = &the_index;
> @@ -746,11 +747,7 @@ static int merge_working_tree(const struct checkout_opts *opts,
>  				       new_branch_info->commit ?
>  				       &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.preserve_ignored = !opts->overwrite_ignore;
>  		tree = parse_tree_indirect(old_branch_info->commit ?
>  					   &old_branch_info->commit->object.oid :
>  					   the_hash_algo->empty_tree);
> @@ -760,10 +757,6 @@ static int merge_working_tree(const struct checkout_opts *opts,
>  		init_tree_desc(&trees[1], tree->buffer, tree->size);
>  
>  		ret = unpack_trees(2, trees, &topts);
> -		if (topts.dir) {
> -			dir_clear(topts.dir);
> -			FREE_AND_NULL(topts.dir);
> -		}
>  		clear_unpack_trees_porcelain(&topts);
>  		if (ret == -1) {
>  			/*
> diff --git a/builtin/clone.c b/builtin/clone.c
> index ff1d3d447a3..be1c3840d62 100644
> --- a/builtin/clone.c
> +++ b/builtin/clone.c
> @@ -687,6 +687,8 @@ static int checkout(int submodule_progress)
>  	opts.update = 1;
>  	opts.merge = 1;
>  	opts.clone = 1;
> +	/* FIXME: Default should be to remove ignored files */
> +	opts.preserve_ignored = 1;
>  	opts.fn = oneway_merge;
>  	opts.verbose_update = (option_verbosity >= 0);
>  	opts.src_index = &the_index;
> diff --git a/builtin/merge.c b/builtin/merge.c
> index 3fbdacc7db4..1e5fff095fc 100644
> --- a/builtin/merge.c
> +++ b/builtin/merge.c
> @@ -680,6 +680,8 @@ static int read_tree_trivial(struct object_id *common, struct object_id *head,
>  	opts.verbose_update = 1;
>  	opts.trivial_merges_only = 1;
>  	opts.merge = 1;
> +	/* FIXME: Default should be to remove ignored files */
> +	opts.preserve_ignored = 1;
>  	trees[nr_trees] = parse_tree_indirect(common);
>  	if (!trees[nr_trees++])
>  		return -1;
> diff --git a/builtin/read-tree.c b/builtin/read-tree.c
> index 73cb957a69b..443d206eca6 100644
> --- a/builtin/read-tree.c
> +++ b/builtin/read-tree.c
> @@ -201,11 +201,9 @@ 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.update && !opts.reset) {
> -		CALLOC_ARRAY(opts.dir, 1);
> -		opts.dir->flags |= DIR_SHOW_IGNORED;
> -		setup_standard_excludes(opts.dir);
> -	}
> +	if (opts.update && !opts.reset)
> +		opts.preserve_ignored = 0;
> +	/* otherwise, opts.preserve_ignored is irrelevant */
>  	if (opts.merge && !opts.index_only)
>  		setup_work_tree();
>  
> @@ -245,11 +243,6 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
>  	if (unpack_trees(nr_trees, t, &opts))
>  		return 128;
>  
> -	if (opts.dir) {
> -		dir_clear(opts.dir);
> -		FREE_AND_NULL(opts.dir);
> -	}
> -
>  	if (opts.debug_unpack || opts.dry_run)
>  		return 0; /* do not write the index out */
>  
> diff --git a/builtin/reset.c b/builtin/reset.c
> index 51c9e2f43ff..7f38656f018 100644
> --- a/builtin/reset.c
> +++ b/builtin/reset.c
> @@ -67,6 +67,8 @@ static int reset_index(const char *ref, const struct object_id *oid, int reset_t
>  	case KEEP:
>  	case MERGE:
>  		opts.update = 1;
> +		/* FIXME: Default should be to remove ignored files */
> +		opts.preserve_ignored = 1;
>  		break;
>  	case HARD:
>  		opts.update = 1;
> diff --git a/builtin/stash.c b/builtin/stash.c
> index 8f42360ca91..88287b890d5 100644
> --- a/builtin/stash.c
> +++ b/builtin/stash.c
> @@ -258,6 +258,9 @@ static int reset_tree(struct object_id *i_tree, int update, int reset)
>  	opts.merge = 1;
>  	opts.reset = reset;
>  	opts.update = update;
> +	if (update && !reset)
> +		/* FIXME: Default should be to remove ignored files */
> +		opts.preserve_ignored = 1;
>  	opts.fn = oneway_merge;
>  
>  	if (unpack_trees(nr_trees, t, &opts))
> diff --git a/merge-ort.c b/merge-ort.c
> index 35aa979c3a4..0d64ec716bd 100644
> --- a/merge-ort.c
> +++ b/merge-ort.c
> @@ -4045,11 +4045,7 @@ static int checkout(struct merge_options *opt,
>  	unpack_opts.quiet = 0; /* FIXME: sequencer might want quiet? */
>  	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.preserve_ignored = 0; /* FIXME: !opts->overwrite_ignore*/
>  	parse_tree(prev);
>  	init_tree_desc(&trees[0], prev->buffer, prev->size);
>  	parse_tree(next);
> @@ -4057,8 +4053,6 @@ 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-recursive.c b/merge-recursive.c
> index 233d9f686ad..2be3f5d4044 100644
> --- a/merge-recursive.c
> +++ b/merge-recursive.c
> @@ -411,9 +411,7 @@ static int unpack_trees_start(struct merge_options *opt,
>  	else {
>  		opt->priv->unpack_opts.update = 1;
>  		/* FIXME: should only do this if !overwrite_ignore */
> -		CALLOC_ARRAY(opt->priv->unpack_opts.dir, 1);
> -		opt->priv->unpack_opts.dir->flags |= DIR_SHOW_IGNORED;
> -		setup_standard_excludes(opt->priv->unpack_opts.dir);
> +		opt->priv->unpack_opts.preserve_ignored = 0;
>  	}
>  	opt->priv->unpack_opts.merge = 1;
>  	opt->priv->unpack_opts.head_idx = 2;
> @@ -428,10 +426,6 @@ static int unpack_trees_start(struct merge_options *opt,
>  	init_tree_desc_from_tree(t+2, merge);
>  
>  	rc = unpack_trees(3, t, &opt->priv->unpack_opts);
> -	if (opt->priv->unpack_opts.dir) {
> -		dir_clear(opt->priv->unpack_opts.dir);
> -		FREE_AND_NULL(opt->priv->unpack_opts.dir);
> -	}
>  	cache_tree_free(&opt->repo->index->cache_tree);
>  
>  	/*
> diff --git a/merge.c b/merge.c
> index 6e736881d90..2382ff66d35 100644
> --- a/merge.c
> +++ b/merge.c
> @@ -53,7 +53,6 @@ int checkout_fast_forward(struct repository *r,
>  	struct unpack_trees_options opts;
>  	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);
> @@ -80,11 +79,7 @@ int checkout_fast_forward(struct repository *r,
>  	}
>  
>  	memset(&opts, 0, sizeof(opts));
> -	if (overwrite_ignore) {
> -		dir.flags |= DIR_SHOW_IGNORED;
> -		setup_standard_excludes(&dir);
> -		opts.dir = &dir;
> -	}
> +	opts.preserve_ignored = !overwrite_ignore;
>  
>  	opts.head_idx = 1;
>  	opts.src_index = r->index;
> @@ -101,7 +96,6 @@ 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/reset.c b/reset.c
> index 79310ae071b..41b3e2d88de 100644
> --- a/reset.c
> +++ b/reset.c
> @@ -56,6 +56,8 @@ int reset_head(struct repository *r, struct object_id *oid, const char *action,
>  	unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
>  	unpack_tree_opts.update = 1;
>  	unpack_tree_opts.merge = 1;
> +	/* FIXME: Default should be to remove ignored files */
> +	unpack_tree_opts.preserve_ignored = 1;
>  	init_checkout_metadata(&unpack_tree_opts.meta, switch_to_branch, oid, NULL);
>  	if (!detach_head)
>  		unpack_tree_opts.reset = 1;
> diff --git a/sequencer.c b/sequencer.c
> index 614d56f5e21..098566c68d9 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -3699,6 +3699,8 @@ static int do_reset(struct repository *r,
>  	unpack_tree_opts.fn = oneway_merge;
>  	unpack_tree_opts.merge = 1;
>  	unpack_tree_opts.update = 1;
> +	/* FIXME: Default should be to remove ignored files */
> +	unpack_tree_opts.preserve_ignored = 1;
>  	init_checkout_metadata(&unpack_tree_opts.meta, name, &oid, NULL);
>  
>  	if (repo_read_index_unmerged(r)) {
> diff --git a/unpack-trees.c b/unpack-trees.c
> index 8ea0a542da8..1e4eae1dc7d 100644
> --- a/unpack-trees.c
> +++ b/unpack-trees.c
> @@ -1707,6 +1707,12 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
>  		ensure_full_index(o->dst_index);
>  	}
>  
> +	if (!o->preserve_ignored) {
> +		CALLOC_ARRAY(o->dir, 1);
> +		o->dir->flags |= DIR_SHOW_IGNORED;
> +		setup_standard_excludes(o->dir);
> +	}
> +
>  	if (!core_apply_sparse_checkout || !o->update)
>  		o->skip_sparse_checkout = 1;
>  	if (!o->skip_sparse_checkout && !o->pl) {
> @@ -1868,6 +1874,10 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
>  done:
>  	if (free_pattern_list)
>  		clear_pattern_list(&pl);
> +	if (o->dir) {
> +		dir_clear(o->dir);
> +		FREE_AND_NULL(o->dir);
> +	}
>  	trace2_region_leave("unpack_trees", "unpack_trees", the_repository);
>  	trace_performance_leave("unpack_trees");
>  	return ret;
> diff --git a/unpack-trees.h b/unpack-trees.h
> index 2d88b19dca7..f98cfd49d7b 100644
> --- a/unpack-trees.h
> +++ b/unpack-trees.h
> @@ -49,6 +49,7 @@ struct unpack_trees_options {
>  	unsigned int reset,
>  		     merge,
>  		     update,
> +		     preserve_ignored,
>  		     clone,
>  		     index_only,
>  		     nontrivial_merge,

I think getting rid of the boilerplate makes sense, but it doesn't sound
from the commit message like you've considered just making that "struct
dir*" member a "struct dir" instead.

That simplifies things a lot, i.e. we can just DIR_INIT it, and don't
need every caller to malloc/free it.

Sometimes a pointer makes sense, but in this case the "struct
unpack_trees_options" can just own it.

As part of WIP leak fixes I have unsubmitted I'd implemented that, patch
follows below.

I think the part of it that deals with managing the "struct dir" is much
nicer, but you might still want to keep the "preserve_ignored" you've
added.

Oh, and I noticed I removed the dir_clear() here but didn't add it to
clear_unpack_trees_porcelain(), that also needs to be done (and I did it
in a later fix that I should squash in), but I can't be bothered to
re-do the below diff just for that, and since the point is how we manage
the struct itself (the freeing is rather trivial...).

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8c69dcdf72a..632da036717 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -747,9 +747,8 @@ 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 485e7b04794..6d529c77c49 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.
@@ -209,7 +206,7 @@ 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 35aa979c3a4..e526b78b88d 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -4021,9 +4021,8 @@ static int checkout(struct merge_options *opt,
 	/* Switch the index/working copy from old to new */
 	int ret;
 	struct tree_desc trees[2];
-	struct unpack_trees_options unpack_opts;
+	struct unpack_trees_options unpack_opts = UNPACK_TREES_OPTIONS_INIT;
 
-	memset(&unpack_opts, 0, sizeof(unpack_opts));
 	unpack_opts.head_idx = -1;
 	unpack_opts.src_index = opt->repo->index;
 	unpack_opts.dst_index = opt->repo->index;
@@ -4046,9 +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);
@@ -4057,8 +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 6e736881d90..9cb32990dd9 100644
--- a/merge.c
+++ b/merge.c
@@ -50,10 +50,9 @@ int checkout_fast_forward(struct repository *r,
 			  int overwrite_ignore)
 {
 	struct tree *trees[MAX_UNPACK_TREES];
-	struct unpack_trees_options opts;
+	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);
@@ -79,11 +78,9 @@ int checkout_fast_forward(struct repository *r,
 		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
 	}
 
-	memset(&opts, 0, sizeof(opts));
 	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;
@@ -101,7 +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 8ea0a542da8..33a2dc23ffc 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -2081,7 +2081,7 @@ 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;
 
@@ -2132,9 +2132,7 @@ 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);
@@ -2175,8 +2173,7 @@ 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 2d88b19dca7..6fa6a4dfc3e 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];
@@ -90,6 +91,9 @@ struct unpack_trees_options {
 	struct pattern_list *pl; /* for internal use */
 	struct checkout_metadata meta;
 };
+#define UNPACK_TREES_OPTIONS_INIT { \
+	.dir = DIR_INIT, \
+}
 
 int unpack_trees(unsigned n, struct tree_desc *t,
 		 struct unpack_trees_options *options);