From f400fbcce2249bd8c48630a5cae1061175bffdfa Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter.hutterer@who-t.net>
Date: Thu, 7 Nov 2024 15:08:39 +1000
Subject: [PATCH] Don't set up styli for devices without a stylus

If a device explicitly lists Stylus=false don't force it
to the generic styli.
---
 libwacom/libwacom-database.c | 14 ++++++++++----
 test/test-tablet-validity.c  | 25 +++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/libwacom/libwacom-database.c b/libwacom/libwacom-database.c
index dee03252..d93e134d 100644
--- a/libwacom/libwacom-database.c
+++ b/libwacom/libwacom-database.c
@@ -748,7 +748,7 @@ libwacom_parse_styli_list(WacomDeviceDatabase *db, WacomDevice *device,
 	guint i;
 
 	array = g_array_new (FALSE, FALSE, sizeof(WacomStylus*));
-	for (i = 0; ids[i]; i++) {
+	for (i = 0; ids && ids[i]; i++) {
 		const char *str = ids[i];
 
 		if (g_str_has_prefix(str, "0x")) {
@@ -949,9 +949,15 @@ libwacom_parse_tablet_keyfile(WacomDeviceDatabase *db,
 
 	string_list = g_key_file_get_string_list(keyfile, DEVICE_GROUP, "Styli", NULL, NULL);
 	if (!string_list) {
-		string_list = g_new0(char*, 3);
-		string_list[0] = g_strdup_printf("0x0:0x%x", WACOM_ERASER_FALLBACK_ID);
-		string_list[1] = g_strdup_printf("0x0:0x%x", WACOM_STYLUS_FALLBACK_ID);
+		GError *error = NULL;
+		if (g_key_file_get_boolean(keyfile, FEATURES_GROUP, "Stylus", &error) ||
+		    g_error_matches (error, G_KEY_FILE_ERROR, G_KEY_FILE_ERROR_KEY_NOT_FOUND)) {
+			string_list = g_new0(char*, 3);
+			string_list[0] = g_strdup_printf("0x0:0x%x", WACOM_ERASER_FALLBACK_ID);
+			string_list[1] = g_strdup_printf("0x0:0x%x", WACOM_STYLUS_FALLBACK_ID);
+		}
+		if (error)
+			g_error_free(error);
 	}
 	libwacom_parse_styli_list(db, device, string_list);
 	g_strfreev (string_list);
diff --git a/test/test-tablet-validity.c b/test/test-tablet-validity.c
index a277c953..03742d77 100644
--- a/test/test-tablet-validity.c
+++ b/test/test-tablet-validity.c
@@ -285,6 +285,29 @@ test_styli(gconstpointer data)
 
 }
 
+static void
+test_no_styli(gconstpointer data)
+{
+	WacomDevice *device = (WacomDevice*)data;
+	int nstylus_ids, nstyli;
+	const WacomStylus **styli;
+	const int *stylus_ids;
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+	stylus_ids = libwacom_get_supported_styli(device, &nstylus_ids);
+#pragma GCC diagnostic pop
+	styli = libwacom_get_styli(device, &nstyli);
+
+	g_assert_cmpint(nstyli, ==, 0);
+	g_assert_cmpint(nstylus_ids, ==, 0);
+	g_assert_nonnull(styli);
+	g_assert_null(stylus_ids);
+	g_assert_null(styli[0]); /* NULL-terminated list */
+	g_free(styli);
+
+}
+
 static void
 test_realstylus(gconstpointer data)
 {
@@ -421,6 +444,8 @@ static void setup_tests(WacomDevice *device)
 	/* FIXME: we force the generic pen for these, should add a test */
 	if (libwacom_has_stylus(device))
 		add_test(device, test_styli);
+	else
+		add_test(device, test_no_styli);
 
 	switch (cls) {
 		case WCLASS_INTUOS: