hal_stream_create: fix bogus error check

hal_stream_create() did not check the return value of
halpr_parse_types() properly, so the stream could be created with any kind of
invalid cfg string.

src/hal/hal_lib.c

@@ -3984,7 +3984,7 @@ int hal_stream_create(hal_stream_t *stream, int comp, int key, int depth, const
     int result = 0;
     hal_type_t type[HAL_STREAM_MAX_PINS];
     result = halpr_parse_types(type, typestring);
-    if(result < 0) return result;
+    if(!result) return -EINVAL;
     int pin_count = result;
 
     size_t size = sizeof(struct hal_stream_shm) + sizeof(union hal_stream_data) * depth * (1+pin_count);

tests/hal-stream/README

@@ -0,0 +1 @@
+Creating a hal stream should fail if the cfg string is invalid.

tests/hal-stream/expected

@@ -0,0 +1 @@
+pass

tests/hal-stream/test.hal

@@ -0,0 +1 @@
+loadusr -w ./test.py

tests/hal-stream/test.py

@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+import hal
+
+c = hal.component("stream_test")
+try:
+    writer = hal.stream(c, hal.streamer_base, 10, "xx")
+except:
+    pass
+else:
+    assert False, "hal.stream should fail with invalid cfg arg"
+
+c.ready()
+print("pass")