Move "show_all_errors = 1" to setup_unpack_trees_porcelain()

Not only this makes the code clearer since setting up the porcelain error
message is meant to work with show_all_errors, but this fixes a call to
setup_unpack_trees_porcelain() in git_merge_trees() which did not set
show_all_errors.

add_rejected_path() used to double-check whether it was running in
plumbing mode. This check was ineffective since it was setting
show_all_errors too late for traverse_trees() to see it, and is made
useless by this patch. Remove it.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/checkout.c

@@ -392,7 +392,6 @@ static int merge_working_tree(struct checkout_opts *opts,
 		topts.dir = xcalloc(1, sizeof(*topts.dir));
 		topts.dir->flags |= DIR_SHOW_IGNORED;
 		topts.dir->exclude_per_dir = ".gitignore";
-		topts.show_all_errors = 1;
 		tree = parse_tree_indirect(old->commit ?
 					   old->commit->object.sha1 :
 					   (unsigned char *)EMPTY_TREE_SHA1_BIN);

builtin/merge.c

@@ -704,7 +704,6 @@ int checkout_fast_forward(const unsigned char *head, const unsigned char *remote
 	opts.verbose_update = 1;
 	opts.merge = 1;
 	opts.fn = twoway_merge;
-	opts.show_all_errors = 1;
 	setup_unpack_trees_porcelain(&opts, "merge");
 
 	trees[nr_trees] = parse_tree_indirect(head);

unpack-trees.c

@@ -94,6 +94,8 @@ void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
 		"The following Working tree files would be overwritten by sparse checkout update:\n%s";
 	msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
 		"The following Working tree files would be removed by sparse checkout update:\n%s";
+
+	opts->show_all_errors = 1;
 }
 
 static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
@@ -120,12 +122,6 @@ static int add_rejected_path(struct unpack_trees_options *o,
 			     const char *path)
 {
 	struct rejected_paths_list *newentry;
-	int porcelain = o && (o)->msgs[e];
-	/*
-	 * simply display the given error message if in plumbing mode
-	 */
-	if (!porcelain)
-		o->show_all_errors = 0;
 	if (!o->show_all_errors)
 		return error(ERRORMSG(o, e), path);
 

unpack-trees.h

@@ -24,7 +24,7 @@ enum unpack_trees_error_types {
 
 /*
  * Sets the list of user-friendly error messages to be used by the
- * command "cmd" (either merge or checkout)
+ * command "cmd" (either merge or checkout), and show_all_errors to 1.
  */
 void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
 				  const char *cmd);