Fix identifier output configs on reload

When generating default output configs to reset the outputs to their
default settings on reload, the output name was being used.
Additionally when determining the output config to apply, if there was
an output config with the output name, that was being used without
checking for an identifier config. This caused sway to completely ignore
the users specified output config.

To fix this issue, the following changes have been made:
1. Default output configs as created for the identifier now instead of
name. This actually makes more sense anyway since you could hotplug
multiple different outputs to the same port.
2. In get_output_config, which is only used to determine which output
config to apply, output configs for both the name and identifier are
queried. If both are found, a new output config is generated with the
identifier config merged on top of the name config. If just one is found,
a copy of that config is returned. This change also requires that the
result from get_output_config be freed after use to prevent memory
leaks, which required some minor changes to logic in
apply_output_config_to_outputs.

sway/config/output.c

@@ -277,17 +277,51 @@ void apply_output_config(struct output_config *oc, struct sway_output *output) {
 }
 
 static struct output_config *get_output_config(char *name, char *identifier) {
+	struct output_config *oc_name = NULL;
 	int i = list_seq_find(config->output_configs, output_name_cmp, name);
 	if (i >= 0) {
-		return config->output_configs->items[i];
+		oc_name = config->output_configs->items[i];
 	}
 
+	struct output_config *oc_id = NULL;
 	i = list_seq_find(config->output_configs, output_name_cmp, identifier);
 	if (i >= 0) {
-		return config->output_configs->items[i];
+		oc_id = config->output_configs->items[i];
 	}
 
-	return NULL;
+	struct output_config *result = NULL;
+	if (oc_name && oc_id) {
+		// Generate a config named `<identifier> on <name>` which contains a
+		// merged copy of the identifier on name. This will make sure that both
+		// identifier and name configs are respected, with identifier getting
+		// priority
+		size_t length = snprintf(NULL, 0, "%s on %s", identifier, name) + 1;
+		char *temp = malloc(length);
+		snprintf(temp, length, "%s on %s", identifier, name);
+
+		result = new_output_config(temp);
+		merge_output_config(result, oc_name);
+		merge_output_config(result, oc_id);
+
+		wlr_log(WLR_DEBUG, "Generated output config \"%s\" (enabled: %d)"
+			" (%dx%d@%fHz position %d,%d scale %f transform %d) (bg %s %s)"
+			" (dpms %d)", result->name, result->enabled, result->width,
+			result->height, result->refresh_rate, result->x, result->y,
+			result->scale, result->transform, result->background,
+			result->background_option, result->dpms_state);
+
+		free(temp);
+	} else if (oc_name) {
+		// No identifier config, just return a copy of the name config
+		result = new_output_config(name);
+		merge_output_config(result, oc_name);
+	} else if (oc_id) {
+		// No name config, just return a copy of the identifier config
+		result = new_output_config(identifier);
+		merge_output_config(result, oc_id);
+	}
+
+	return result;
 }
 
 void apply_output_config_to_outputs(struct output_config *oc) {
@@ -301,14 +335,17 @@ void apply_output_config_to_outputs(struct output_config *oc) {
 		char *name = sway_output->wlr_output->name;
 		output_get_identifier(id, sizeof(id), sway_output);
 		if (wildcard || !strcmp(name, oc->name) || !strcmp(id, oc->name)) {
-			struct output_config *current = oc;
+			struct output_config *current = new_output_config(oc->name);
+			merge_output_config(current, oc);
 			if (wildcard) {
 				struct output_config *tmp = get_output_config(name, id);
 				if (tmp) {
+					free_output_config(current);
 					current = tmp;
 				}
 			}
 			apply_output_config(current, sway_output);
+			free_output_config(current);
 
 			if (!wildcard) {
 				// Stop looking if the output config isn't applicable to all
@@ -348,8 +385,9 @@ static void default_output_config(struct output_config *oc,
 void create_default_output_configs(void) {
 	struct sway_output *sway_output;
 	wl_list_for_each(sway_output, &root->all_outputs, link) {
-		char *name = sway_output->wlr_output->name;
-		struct output_config *oc = new_output_config(name);
+		char id[128];
+		output_get_identifier(id, sizeof(id), sway_output);
+		struct output_config *oc = new_output_config(id);
 		default_output_config(oc, sway_output->wlr_output);
 		list_add(config->output_configs, oc);
 	}