lib-oauth2: Make sure fields are always initialized

src/lib-oauth2/oauth2-introspect.c

@@ -47,6 +47,7 @@ oauth2_introspect_response(const struct http_response *response,
 			oauth2_introspect_continue(req, FALSE, "Missing response body");
 			return;
 		}
+		p_array_init(&req->fields, req->pool, 1);
 		req->is = response->payload;
 		i_stream_ref(req->is);
 		req->parser = json_parser_init(req->is);

src/lib-oauth2/oauth2-refresh.c

@@ -87,6 +87,7 @@ oauth2_refresh_response(const struct http_response *response,
 			oauth2_refresh_continue(req, FALSE, "Missing response body");
 			return;
 		}
+		p_array_init(&req->fields, req->pool, 1);
 		req->is = response->payload;
 		i_stream_ref(req->is);
 		req->parser = json_parser_init(req->is);

src/lib-oauth2/oauth2-token-validate.c

@@ -30,6 +30,8 @@ oauth2_token_validate_continue(struct oauth2_request *req, bool success,
 	struct oauth2_token_validation_result res;
 	i_zero(&res);
 
+	i_assert(array_is_created(&req->fields));
+
 	res.success = success;
 	res.error = error;
 	res.valid = req->valid;
@@ -69,9 +71,9 @@ oauth2_token_validate_response(const struct http_response *response,
 			req->valid = TRUE;
 		else
 			req->valid = FALSE;
+		p_array_init(&req->fields, req->pool, 1);
 		/* 2xx is sufficient for token validation */
 		if (response->payload == NULL) {
-			p_array_init(&req->fields, req->pool, 1);
 			oauth2_token_validate_continue(req, TRUE, NULL);
 			return;
 		}