Fix @optional for string literals (#905)

Signed-off-by: Michael Carlstrom <[email protected]>

Author: InvincibleRMC

rosidl_adapter/rosidl_adapter/parser.py

@@ -530,8 +530,7 @@ def parse_message_string(pkg_name: str, msg_name: str,
             if not line:
                 continue
 
-        annotation_index = line.rfind(OPTIONAL_ANNOTATION)
-        if annotation_index >= 0:
+        if line.startswith(OPTIONAL_ANNOTATION):
             if is_optional:
                 raise MultipleOptionalAnnotations(
                     f'Already declared @optional. Error detected with {line}.')

rosidl_adapter/test/data/msg/Test.expected.idl

@@ -8,6 +8,8 @@ module test_msgs {
     module Test_Constants {
       @optional
       const float INLINE_CONSTANT = 32.0;
+      @optional
+      const string OPTIONAL_STRING_CONST = "@optional";
     };
     @verbatim (language="comment", text=
       "msg level doc")
@@ -54,6 +56,10 @@ module test_msgs {
       @optional
       @default (value=32.0)
       float inline_default_optional;
+
+      @optional
+      @default (value="@optional")
+      string optional_default_string;
     };
   };
 };

rosidl_adapter/test/data/msg/Test.msg

@@ -22,3 +22,6 @@ float32 multiline_optional
 @optional float32 inline_optional
 @optional float32 inline_default_optional 32.0
 @optional float32 INLINE_CONSTANT=32.0
+
+@optional string optional_default_string @optional
+@optional string OPTIONAL_STRING_CONST=@optional