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.

1 files changed, 24 insertions, 19 deletions

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 == "") {