Export: Improve usability of command line interface

I'm barely scratching the surface of the changes needed to make the
--export command line interface easy to use, but this should already
improve things somewhat.

- Streamline `can_export()` templates check in all platforms, checking
  first for the presence of official templates, then of any defined
  custom template, and reporting on the absence of any.
  Shouldn't change the actual return value much which is still true if
  either release or debug is usable - we might want to change that
  eventually and better validate against the requested target.

- Fix discrepancy between platforms using `custom_package/debug` and
  `custom_template/debug` (resp. `release`).
  All now use `custom_template`, which will break compatibility for
  `export_presets.cfg` with earlier projects (but is easy to fix).

- Use `can_export()` when attempting a command line export and report
  the same errors that would be shown in the editor.

- Improve error reporting after a failed export attempt, handling
  missing template and invalid path more gracefully.

- Cleanup of unused stuff in EditorNode around the export workflow.

- Improve --export documentation in --help a bit.

Fixes #16949 (at least many of the misunderstandings listed there).
Fixes #18470.

9 files changed, 156 insertions, 173 deletions

diff --git a/editor/editor_export.cpp b/editor/editor_export.cpp
index 264206472b..d66b386f93 100644
--- a/editor/editor_export.cpp
+++ b/editor/editor_export.cpp
@@ -1485,41 +1485,29 @@ Ref<Texture> EditorExportPlatformPC::get_logo() const {
 bool EditorExportPlatformPC::can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const {
 
 	String err;
-	bool valid = true;
-	bool use64 = p_preset->get("binary_format/64_bits");
-
-	if (use64 && (!exists_export_template(debug_file_64, &err) || !exists_export_template(release_file_64, &err))) {
-		valid = false;
-	}
+	bool valid = false;
 
-	if (!use64 && (!exists_export_template(debug_file_32, &err) || !exists_export_template(release_file_32, &err))) {
-		valid = false;
-	}
-
-	String custom_debug_binary = p_preset->get("custom_template/debug");
-	String custom_release_binary = p_preset->get("custom_template/release");
+	// Look for export templates (first official, and if defined custom templates).
 
-	if (custom_debug_binary == "" && custom_release_binary == "") {
-		if (!err.empty())
-			r_error = err;
-		r_missing_templates = !valid;
-		return valid;
-	}
-
-	bool dvalid = true;
-	bool rvalid = true;
+	bool use64 = p_preset->get("binary_format/64_bits");
+	bool dvalid = exists_export_template(use64 ? debug_file_64 : debug_file_32, &err);
+	bool rvalid = exists_export_template(use64 ? release_file_64 : release_file_32, &err);
 
-	if (!FileAccess::exists(custom_debug_binary)) {
-		dvalid = false;
-		err += TTR("Custom debug template not found.") + "\n";
+	if (p_preset->get("custom_template/debug") != "") {
+		dvalid = FileAccess::exists(p_preset->get("custom_template/debug"));
+		if (!dvalid) {
+			err += TTR("Custom debug template not found.") + "\n";
+		}
 	}
-
-	if (!FileAccess::exists(custom_release_binary)) {
-		rvalid = false;
-		err += TTR("Custom release template not found.") + "\n";
+	if (p_preset->get("custom_template/release") != "") {
+		rvalid = FileAccess::exists(p_preset->get("custom_template/release"));
+		if (!rvalid) {
+			err += TTR("Custom release template not found.") + "\n";
+		}
 	}
 
 	valid = dvalid || rvalid;
+	r_missing_templates = !valid;
 
 	if (!err.empty())
 		r_error = err;
@@ -1600,7 +1588,7 @@ Error EditorExportPlatformPC::export_project(const Ref<EditorExportPreset> &p_pr
 
 			if (embedded_size >= 0x100000000 && !p_preset->get("binary_format/64_bits")) {
 				EditorNode::get_singleton()->show_warning(TTR("On 32-bit exports the embedded PCK cannot be bigger than 4 GiB."));
-				return ERR_UNAVAILABLE;
+				return ERR_INVALID_PARAMETER;
 			}
 
 			FixUpEmbeddedPckFunc fixup_func = get_fixup_embedded_pck_func();
diff --git a/editor/editor_node.cpp b/editor/editor_node.cpp
index 8e6668bc89..d7bc959729 100644
--- a/editor/editor_node.cpp
+++ b/editor/editor_node.cpp
@@ -562,46 +562,68 @@ void EditorNode::_fs_changed() {
 
 	_mark_unsaved_scenes();
 
+	// FIXME: Move this to a cleaner location, it's hacky to do this is _fs_changed.
+	String export_error;
 	if (export_defer.preset != "" && !EditorFileSystem::get_singleton()->is_scanning()) {
+		String preset_name = export_defer.preset;
+		// Ensures export_project does not loop infinitely, because notifications may
+		// come during the export.
+		export_defer.preset = "";
 		Ref<EditorExportPreset> preset;
 		for (int i = 0; i < EditorExport::get_singleton()->get_export_preset_count(); ++i) {
 			preset = EditorExport::get_singleton()->get_export_preset(i);
-			if (preset->get_name() == export_defer.preset) {
+			if (preset->get_name() == preset_name) {
 				break;
 			}
 			preset.unref();
 		}
 		if (preset.is_null()) {
-			String errstr = "Unknown export preset: " + export_defer.preset;
-			ERR_PRINTS(errstr);
-			OS::get_singleton()->set_exit_code(EXIT_FAILURE);
+			export_error = vformat("Invalid export preset name: %s.", preset_name);
 		} else {
 			Ref<EditorExportPlatform> platform = preset->get_platform();
 			if (platform.is_null()) {
-				String errstr = "Preset \"" + export_defer.preset + "\" doesn't have a platform.";
-				ERR_PRINTS(errstr);
-				OS::get_singleton()->set_exit_code(EXIT_FAILURE);
+				export_error = vformat("Export preset '%s' doesn't have a matching platform.", preset_name);
 			} else {
-				// ensures export_project does not loop infinitely, because notifications may
-				// come during the export
-				export_defer.preset = "";
 				Error err = OK;
+				// FIXME: This way to export only resources .pck or .zip is pretty hacky
+				// and undocumented, and might be problematic for platforms where .zip is
+				// a valid project export format (e.g. macOS).
 				if (export_defer.path.ends_with(".pck") || export_defer.path.ends_with(".zip")) {
 					if (export_defer.path.ends_with(".zip")) {
 						err = platform->export_zip(preset, export_defer.debug, export_defer.path);
 					} else if (export_defer.path.ends_with(".pck")) {
 						err = platform->export_pack(preset, export_defer.debug, export_defer.path);
 					}
-				} else {
-					err = platform->export_project(preset, export_defer.debug, export_defer.path);
+				} else { // Normal project export.
+					String config_error;
+					bool missing_templates;
+					if (!platform->can_export(preset, config_error, missing_templates)) {
+						ERR_PRINT(vformat("Cannot export project with preset '%s' due to configuration errors:\n%s", preset_name, config_error));
+						err = missing_templates ? ERR_FILE_NOT_FOUND : ERR_UNCONFIGURED;
+					} else {
+						err = platform->export_project(preset, export_defer.debug, export_defer.path);
+					}
 				}
-				if (err != OK) {
-					ERR_PRINTS(vformat(TTR("Project export failed with error code %d."), (int)err));
-					OS::get_singleton()->set_exit_code(EXIT_FAILURE);
+				switch (err) {
+					case OK:
+						break;
+					case ERR_FILE_NOT_FOUND:
+						export_error = vformat("Project export failed for preset '%s', the export template appears to be missing.", preset_name);
+						break;
+					case ERR_FILE_BAD_PATH:
+						export_error = vformat("Project export failed for preset '%s', the target path '%s' appears to be invalid.", preset_name, export_defer.path);
+						break;
+					default:
+						export_error = vformat("Project export failed with error code %d for preset '%s'.", (int)err, preset_name);
+						break;
 				}
 			}
 		}
 
+		if (!export_error.empty()) {
+			ERR_PRINT(export_error);
+			OS::get_singleton()->set_exit_code(EXIT_FAILURE);
+		}
 		_exit_editor();
 	}
 }
@@ -3920,12 +3942,11 @@ void EditorNode::_editor_file_dialog_unregister(EditorFileDialog *p_dialog) {
 
 Vector<EditorNodeInitCallback> EditorNode::_init_callbacks;
 
-Error EditorNode::export_preset(const String &p_preset, const String &p_path, bool p_debug, const String &p_password, bool p_quit_after) {
+Error EditorNode::export_preset(const String &p_preset, const String &p_path, bool p_debug) {
 
 	export_defer.preset = p_preset;
 	export_defer.path = p_path;
 	export_defer.debug = p_debug;
-	export_defer.password = p_password;
 	disable_progress_dialog = true;
 	return OK;
 }
@@ -6531,12 +6552,6 @@ EditorNode::EditorNode() {
 	gui_base->add_child(file);
 	file->set_current_dir("res://");
 
-	file_export = memnew(EditorFileDialog);
-	file_export->set_access(EditorFileDialog::ACCESS_FILESYSTEM);
-	gui_base->add_child(file_export);
-	file_export->set_title(TTR("Export Project"));
-	file_export->connect("file_selected", this, "_dialog_action");
-
 	file_export_lib = memnew(EditorFileDialog);
 	file_export_lib->set_title(TTR("Export Library"));
 	file_export_lib->set_mode(EditorFileDialog::MODE_SAVE_FILE);
@@ -6547,11 +6562,6 @@ EditorNode::EditorNode() {
 	file_export_lib->get_vbox()->add_child(file_export_lib_merge);
 	gui_base->add_child(file_export_lib);
 
-	file_export_password = memnew(LineEdit);
-	file_export_password->set_secret(true);
-	file_export_password->set_editable(false);
-	file_export->get_vbox()->add_margin_child(TTR("Password:"), file_export_password);
-
 	file_script = memnew(EditorFileDialog);
 	file_script->set_title(TTR("Open & Run a Script"));
 	file_script->set_access(EditorFileDialog::ACCESS_FILESYSTEM);
diff --git a/editor/editor_node.h b/editor/editor_node.h
index acff91790d..469ba76872 100644
--- a/editor/editor_node.h
+++ b/editor/editor_node.h
@@ -325,18 +325,13 @@ private:
 	ExportTemplateManager *export_template_manager;
 	EditorFeatureProfileManager *feature_profile_manager;
 	EditorFileDialog *file_templates;
-	EditorFileDialog *file_export;
 	EditorFileDialog *file_export_lib;
 	EditorFileDialog *file_script;
 	CheckBox *file_export_lib_merge;
-	LineEdit *file_export_password;
 	String current_path;
 	MenuButton *update_spinner;
 
 	String defer_load_scene;
-	String defer_export;
-	String defer_export_platform;
-	bool defer_export_debug;
 	Node *_last_instanced_scene;
 
 	EditorLog *log;
@@ -563,8 +558,6 @@ private:
 		String preset;
 		String path;
 		bool debug;
-		String password;
-
 	} export_defer;
 
 	bool disable_progress_dialog;
@@ -786,7 +779,7 @@ public:
 
 	void _copy_warning(const String &p_str);
 
-	Error export_preset(const String &p_preset, const String &p_path, bool p_debug, const String &p_password, bool p_quit_after = false);
+	Error export_preset(const String &p_preset, const String &p_path, bool p_debug);
 
 	static void register_editor_types();
 	static void unregister_editor_types();
diff --git a/main/main.cpp b/main/main.cpp
index 2bcea5cb7d..308c53de13 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -286,8 +286,10 @@ void Main::print_help(const char *p_binary) {
 	OS::get_singleton()->print("  -s, --script <script>            Run a script.\n");
 	OS::get_singleton()->print("  --check-only                     Only parse for errors and quit (use with --script).\n");
 #ifdef TOOLS_ENABLED
-	OS::get_singleton()->print("  --export <target> <path>         Export the project using the given export target. Export only main pack if path ends with .pck or .zip. <path> is relative to the project directory.\n");
-	OS::get_singleton()->print("  --export-debug <target> <path>   Like --export, but use debug template.\n");
+	OS::get_singleton()->print("  --export <preset> <path>         Export the project using the given preset and matching release template. The preset name should match one defined in export_presets.cfg.\n");
+	OS::get_singleton()->print("                                   <path> should be absolute or relative to the project directory, and include the filename for the binary (e.g. 'builds/game.exe').\n");
+	OS::get_singleton()->print("                                   The target directory should exist. Only the data pack is exported if <path> ends with .pck or .zip.\n");
+	OS::get_singleton()->print("  --export-debug <preset> <path>   Same as --export, but using the debug template.\n");
 	OS::get_singleton()->print("  --doctool <path>                 Dump the engine API reference to the given <path> in XML format, merging if existing files are found.\n");
 	OS::get_singleton()->print("  --no-docbase                     Disallow dumping the base types (used with --doctool).\n");
 	OS::get_singleton()->print("  --build-solutions                Build the scripting solutions (e.g. for C# projects).\n");
@@ -1513,11 +1515,11 @@ bool Main::start() {
 
 	if (_export_preset != "") {
 		if (game_path == "") {
-			String err = "Command line param ";
+			String err = "Command line parameter ";
 			err += export_debug ? "--export-debug" : "--export";
 			err += " passed but no destination path given.\n";
 			err += "Please specify the binary's file path to export to. Aborting export.";
-			ERR_PRINT(err.utf8().get_data());
+			ERR_PRINT(err);
 			return false;
 		}
 	}
@@ -1698,20 +1700,14 @@ bool Main::start() {
 		}
 
 #ifdef TOOLS_ENABLED
-
 		EditorNode *editor_node = NULL;
 		if (editor) {
-
 			editor_node = memnew(EditorNode);
 			sml->get_root()->add_child(editor_node);
 
-			//root_node->set_editor(editor);
-			//startup editor
-
 			if (_export_preset != "") {
-
-				editor_node->export_preset(_export_preset, game_path, export_debug, "", true);
-				game_path = ""; //no load anything
+				editor_node->export_preset(_export_preset, game_path, export_debug);
+				game_path = ""; // Do not load anything.
 			}
 		}
 #endif
diff --git a/platform/android/export/export.cpp b/platform/android/export/export.cpp
index 9167a291f8..d7a72779e6 100644
--- a/platform/android/export/export.cpp
+++ b/platform/android/export/export.cpp
@@ -1299,9 +1299,9 @@ public:
 		r_options->push_back(ExportOption(PropertyInfo(Variant::INT, "graphics/degrees_of_freedom", PROPERTY_HINT_ENUM, "None,3DOF and 6DOF,6DOF"), 0));
 		r_options->push_back(ExportOption(PropertyInfo(Variant::BOOL, "graphics/32_bits_framebuffer"), true));
 		r_options->push_back(ExportOption(PropertyInfo(Variant::BOOL, "one_click_deploy/clear_previous_install"), false));
-		r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_package/debug", PROPERTY_HINT_GLOBAL_FILE, "*.apk"), ""));
-		r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_package/release", PROPERTY_HINT_GLOBAL_FILE, "*.apk"), ""));
-		r_options->push_back(ExportOption(PropertyInfo(Variant::BOOL, "custom_package/use_custom_build"), false));
+		r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_template/debug", PROPERTY_HINT_GLOBAL_FILE, "*.apk"), ""));
+		r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_template/release", PROPERTY_HINT_GLOBAL_FILE, "*.apk"), ""));
+		r_options->push_back(ExportOption(PropertyInfo(Variant::BOOL, "custom_template/use_custom_build"), false));
 		r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "command_line/extra_args"), ""));
 		r_options->push_back(ExportOption(PropertyInfo(Variant::INT, "version/code", PROPERTY_HINT_RANGE, "1,4096,1,or_greater"), 1));
 		r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "version/name"), "1.0"));
@@ -1577,29 +1577,34 @@ public:
 	virtual bool can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const {
 
 		String err;
+		bool valid = false;
 
-		if (!bool(p_preset->get("custom_package/use_custom_build"))) {
+		// Look for export templates (first official, and if defined custom templates).
 
-			r_missing_templates = find_export_template("android_debug.apk") == String() || find_export_template("android_release.apk") == String();
+		if (!bool(p_preset->get("custom_template/use_custom_build"))) {
+			bool dvalid = exists_export_template("android_debug.apk", &err);
+			bool rvalid = exists_export_template("android_release.apk", &err);
 
-			if (p_preset->get("custom_package/debug") != "") {
-				if (FileAccess::exists(p_preset->get("custom_package/debug"))) {
-					r_missing_templates = false;
-				} else {
+			if (p_preset->get("custom_template/debug") != "") {
+				dvalid = FileAccess::exists(p_preset->get("custom_template/debug"));
+				if (!dvalid) {
 					err += TTR("Custom debug template not found.") + "\n";
 				}
 			}
-
-			if (p_preset->get("custom_package/release") != "") {
-				if (FileAccess::exists(p_preset->get("custom_package/release"))) {
-					r_missing_templates = false;
-				} else {
+			if (p_preset->get("custom_template/release") != "") {
+				rvalid = FileAccess::exists(p_preset->get("custom_template/release"));
+				if (!rvalid) {
 					err += TTR("Custom release template not found.") + "\n";
 				}
 			}
+
+			valid = dvalid || rvalid;
+		} else {
+			valid = exists_export_template("android_source.zip", &err);
 		}
+		r_missing_templates = !valid;
 
-		bool valid = !r_missing_templates;
+		// Validate the rest of the configuration.
 
 		String adb = EditorSettings::get_singleton()->get("export/android/adb");
 
@@ -1628,7 +1633,7 @@ public:
 			}
 		}
 
-		if (bool(p_preset->get("custom_package/use_custom_build"))) {
+		if (bool(p_preset->get("custom_template/use_custom_build"))) {
 			String sdk_path = EditorSettings::get_singleton()->get("export/android/custom_build_sdk_path");
 			if (sdk_path == "") {
 				err += TTR("Custom build requires a valid Android SDK path in Editor Settings.") + "\n";
@@ -1949,7 +1954,7 @@ public:
 
 		EditorProgress ep("export", "Exporting for Android", 105, true);
 
-		if (bool(p_preset->get("custom_package/use_custom_build"))) { //custom build
+		if (bool(p_preset->get("custom_template/use_custom_build"))) { //custom build
 			//re-generate build.gradle and AndroidManifest.xml
 
 			{ //test that installed build version is alright
@@ -2017,9 +2022,9 @@ public:
 		} else {
 
 			if (p_debug)
-				src_apk = p_preset->get("custom_package/debug");
+				src_apk = p_preset->get("custom_template/debug");
 			else
-				src_apk = p_preset->get("custom_package/release");
+				src_apk = p_preset->get("custom_template/release");
 
 			src_apk = src_apk.strip_edges();
 			if (src_apk == "") {
diff --git a/platform/iphone/export/export.cpp b/platform/iphone/export/export.cpp
index c80370847d..b606d570c2 100644
--- a/platform/iphone/export/export.cpp
+++ b/platform/iphone/export/export.cpp
@@ -206,8 +206,8 @@ static const LoadingScreenInfo loading_screen_infos[] = {
 
 void EditorExportPlatformIOS::get_export_options(List<ExportOption> *r_options) {
 
-	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_package/debug", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
-	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_package/release", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
+	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_template/debug", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
+	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_template/release", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
 
 	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "application/app_store_team_id"), ""));
 
@@ -848,9 +848,9 @@ Error EditorExportPlatformIOS::export_project(const Ref<EditorExportPreset> &p_p
 	ERR_FAIL_COND_V_MSG(team_id.length() == 0, ERR_CANT_OPEN, "App Store Team ID not specified - cannot configure the project.");
 
 	if (p_debug)
-		src_pkg_name = p_preset->get("custom_package/debug");
+		src_pkg_name = p_preset->get("custom_template/debug");
 	else
-		src_pkg_name = p_preset->get("custom_package/release");
+		src_pkg_name = p_preset->get("custom_template/release");
 
 	if (src_pkg_name == "") {
 		String err;
@@ -1156,25 +1156,30 @@ Error EditorExportPlatformIOS::export_project(const Ref<EditorExportPreset> &p_p
 bool EditorExportPlatformIOS::can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const {
 
 	String err;
-	r_missing_templates = find_export_template("iphone.zip") == String();
+	bool valid = false;
 
-	if (p_preset->get("custom_package/debug") != "") {
-		if (FileAccess::exists(p_preset->get("custom_package/debug"))) {
-			r_missing_templates = false;
-		} else {
+	// Look for export templates (first official, and if defined custom templates).
+
+	bool dvalid = exists_export_template("iphone.zip", &err);
+	bool rvalid = dvalid; // Both in the same ZIP.
+
+	if (p_preset->get("custom_template/debug") != "") {
+		dvalid = FileAccess::exists(p_preset->get("custom_template/debug"));
+		if (!dvalid) {
 			err += TTR("Custom debug template not found.") + "\n";
 		}
 	}
-
-	if (p_preset->get("custom_package/release") != "") {
-		if (FileAccess::exists(p_preset->get("custom_package/release"))) {
-			r_missing_templates = false;
-		} else {
+	if (p_preset->get("custom_template/release") != "") {
+		rvalid = FileAccess::exists(p_preset->get("custom_template/release"));
+		if (!rvalid) {
 			err += TTR("Custom release template not found.") + "\n";
 		}
 	}
 
-	bool valid = !r_missing_templates;
+	valid = dvalid || rvalid;
+	r_missing_templates = !valid;
+
+	// Validate the rest of the configuration.
 
 	String team_id = p_preset->get("application/app_store_team_id");
 	if (team_id.length() == 0) {
diff --git a/platform/javascript/export/export.cpp b/platform/javascript/export/export.cpp
index bbdf6a1f57..93c83f4ff4 100644
--- a/platform/javascript/export/export.cpp
+++ b/platform/javascript/export/export.cpp
@@ -288,32 +288,32 @@ Ref<Texture> EditorExportPlatformJavaScript::get_logo() const {
 
 bool EditorExportPlatformJavaScript::can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const {
 
-	bool valid = false;
 	String err;
+	bool valid = false;
 
-	if (find_export_template(EXPORT_TEMPLATE_WEBASSEMBLY_RELEASE) != "")
-		valid = true;
-	else if (find_export_template(EXPORT_TEMPLATE_WEBASSEMBLY_DEBUG) != "")
-		valid = true;
+	// Look for export templates (first official, and if defined custom templates).
+
+	bool dvalid = exists_export_template(EXPORT_TEMPLATE_WEBASSEMBLY_DEBUG, &err);
+	bool rvalid = exists_export_template(EXPORT_TEMPLATE_WEBASSEMBLY_RELEASE, &err);
 
 	if (p_preset->get("custom_template/debug") != "") {
-		if (FileAccess::exists(p_preset->get("custom_template/debug"))) {
-			valid = true;
-		} else {
+		dvalid = FileAccess::exists(p_preset->get("custom_template/debug"));
+		if (!dvalid) {
 			err += TTR("Custom debug template not found.") + "\n";
 		}
 	}
-
 	if (p_preset->get("custom_template/release") != "") {
-		if (FileAccess::exists(p_preset->get("custom_template/release"))) {
-			valid = true;
-		} else {
+		rvalid = FileAccess::exists(p_preset->get("custom_template/release"));
+		if (!rvalid) {
 			err += TTR("Custom release template not found.") + "\n";
 		}
 	}
 
+	valid = dvalid || rvalid;
 	r_missing_templates = !valid;
 
+	// Validate the rest of the configuration.
+
 	if (p_preset->get("vram_texture_compression/for_mobile")) {
 		String etc_error = test_etc2();
 		if (etc_error != String()) {
diff --git a/platform/osx/export/export.cpp b/platform/osx/export/export.cpp
index dd98a98996..ce7b47c414 100644
--- a/platform/osx/export/export.cpp
+++ b/platform/osx/export/export.cpp
@@ -118,8 +118,8 @@ void EditorExportPlatformOSX::get_preset_features(const Ref<EditorExportPreset>
 
 void EditorExportPlatformOSX::get_export_options(List<ExportOption> *r_options) {
 
-	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_package/debug", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
-	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_package/release", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
+	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_template/debug", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
+	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "custom_template/release", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
 
 	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "application/name", PROPERTY_HINT_PLACEHOLDER_TEXT, "Game Name"), ""));
 	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "application/info"), "Made with Godot Engine"));
@@ -459,9 +459,9 @@ Error EditorExportPlatformOSX::export_project(const Ref<EditorExportPreset> &p_p
 	EditorProgress ep("export", "Exporting for OSX", 3, true);
 
 	if (p_debug)
-		src_pkg_name = p_preset->get("custom_package/debug");
+		src_pkg_name = p_preset->get("custom_template/debug");
 	else
-		src_pkg_name = p_preset->get("custom_package/release");
+		src_pkg_name = p_preset->get("custom_template/release");
 
 	if (src_pkg_name == "") {
 		String err;
@@ -796,33 +796,32 @@ Error EditorExportPlatformOSX::export_project(const Ref<EditorExportPreset> &p_p
 
 bool EditorExportPlatformOSX::can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const {
 
-	bool valid = false;
 	String err;
+	bool valid = false;
 
-	if (exists_export_template("osx.zip", &err)) {
-		valid = true;
-	}
+	// Look for export templates (first official, and if defined custom templates).
 
-	if (p_preset->get("custom_package/debug") != "") {
-		if (FileAccess::exists(p_preset->get("custom_package/debug"))) {
-			valid = true;
-		} else {
+	bool dvalid = exists_export_template("osx.zip", &err);
+	bool rvalid = dvalid; // Both in the same ZIP.
+
+	if (p_preset->get("custom_template/debug") != "") {
+		dvalid = FileAccess::exists(p_preset->get("custom_template/debug"));
+		if (!dvalid) {
 			err += TTR("Custom debug template not found.") + "\n";
 		}
 	}
-
-	if (p_preset->get("custom_package/release") != "") {
-		if (FileAccess::exists(p_preset->get("custom_package/release"))) {
-			valid = true;
-		} else {
+	if (p_preset->get("custom_template/release") != "") {
+		rvalid = FileAccess::exists(p_preset->get("custom_template/release"));
+		if (!rvalid) {
 			err += TTR("Custom release template not found.") + "\n";
 		}
 	}
 
+	valid = dvalid || rvalid;
+	r_missing_templates = !valid;
+
 	if (!err.empty())
 		r_error = err;
-
-	r_missing_templates = !valid;
 	return valid;
 }
 
diff --git a/platform/uwp/export/export.cpp b/platform/uwp/export/export.cpp
index 3fa5512819..57fb9004b8 100644
--- a/platform/uwp/export/export.cpp
+++ b/platform/uwp/export/export.cpp
@@ -1090,15 +1090,14 @@ public:
 	}
 
 	virtual bool can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const {
+
 		String err;
-		bool valid = true;
-		Platform arch = (Platform)(int)(p_preset->get("architecture/target"));
+		bool valid = false;
 
-		String custom_debug_binary = p_preset->get("custom_template/debug");
-		String custom_release_binary = p_preset->get("custom_template/release");
+		// Look for export templates (first official, and if defined custom templates).
 
+		Platform arch = (Platform)(int)(p_preset->get("architecture/target"));
 		String platform_infix;
-
 		switch (arch) {
 			case EditorExportPlatformUWP::ARM: {
 				platform_infix = "arm";
@@ -1111,38 +1110,26 @@ public:
 			} break;
 		}
 
-		if (!exists_export_template("uwp_" + platform_infix + "_debug.zip", &err) || !exists_export_template("uwp_" + platform_infix + "_release.zip", &err)) {
-			valid = false;
-			r_missing_templates = true;
-		}
+		bool dvalid = exists_export_template("uwp_" + platform_infix + "_debug.zip", &err);
+		bool rvalid = exists_export_template("uwp_" + platform_infix + "_release.zip", &err);
 
-		if (!valid && custom_debug_binary == "" && custom_release_binary == "") {
-			if (!err.empty()) {
-				r_error = err;
+		if (p_preset->get("custom_template/debug") != "") {
+			dvalid = FileAccess::exists(p_preset->get("custom_template/debug"));
+			if (!dvalid) {
+				err += TTR("Custom debug template not found.") + "\n";
 			}
-			return valid;
 		}
-
-		bool dvalid = true;
-		bool rvalid = true;
-
-		if (!FileAccess::exists(custom_debug_binary)) {
-			dvalid = false;
-			err += TTR("Custom debug template not found.") + "\n";
-		}
-
-		if (!FileAccess::exists(custom_release_binary)) {
-			rvalid = false;
-			err += TTR("Custom release template not found.") + "\n";
+		if (p_preset->get("custom_template/release") != "") {
+			rvalid = FileAccess::exists(p_preset->get("custom_template/release"));
+			if (!rvalid) {
+				err += TTR("Custom release template not found.") + "\n";
+			}
 		}
 
-		if (dvalid || rvalid)
-			valid = true;
+		valid = dvalid || rvalid;
+		r_missing_templates = !valid;
 
-		if (!valid) {
-			r_error = err;
-			return valid;
-		}
+		// Validate the rest of the configuration.
 
 		if (!_valid_resource_name(p_preset->get("package/short_name"))) {
 			valid = false;