refactor: value_to_string now returns a String, instead of Option<String>

After the refactor from the previous commit, it became obvious, that the
function value_to_string() can never return a None value. Therefore, it's
useless that it returns an Option<String>, so it was changed to return a String.
This lead to a lot of code simplification.

Author: nickysn

gems/codetracer-ruby-recorder/ext/native_tracer/src/lib.rs

@@ -301,11 +301,11 @@ unsafe fn rstring_lossy(val: VALUE) -> String {
     String::from_utf8_lossy(slice).to_string()
 }
 
-unsafe fn value_to_string(recorder: &Recorder, val: VALUE) -> Option<String> {
+unsafe fn value_to_string(recorder: &Recorder, val: VALUE) -> String {
     if RB_TYPE_P(val, rb_sys::ruby_value_type::RUBY_T_STRING) {
-        Some(rstring_lossy(val))
+        rstring_lossy(val)
     } else {
-        Some(rstring_lossy(rb_funcall(val, recorder.id.to_s, 0)))
+        rstring_lossy(rb_funcall(val, recorder.id.to_s, 0))
     }
 }
 
@@ -477,7 +477,7 @@ unsafe fn to_value(recorder: &mut Recorder, val: VALUE, depth: usize) -> ValueRe
         if !RB_TYPE_P(members, rb_sys::ruby_value_type::RUBY_T_ARRAY)
             || !RB_TYPE_P(values, rb_sys::ruby_value_type::RUBY_T_ARRAY)
         {
-            let text = value_to_string(recorder, val).unwrap_or_default();
+            let text = value_to_string(recorder, val);
             let type_id =
                 TraceWriter::ensure_type_id(&mut *recorder.tracer, TypeKind::Raw, &class_name);
             return ValueRecord::Raw { r: text, type_id };
@@ -511,7 +511,7 @@ unsafe fn to_value(recorder: &mut Recorder, val: VALUE, depth: usize) -> ValueRe
     // generic object
     let ivars = rb_funcall(val, recorder.id.instance_variables, 0);
     if !RB_TYPE_P(ivars, rb_sys::ruby_value_type::RUBY_T_ARRAY) {
-        let text = value_to_string(recorder, val).unwrap_or_default();
+        let text = value_to_string(recorder, val);
         let type_id =
             TraceWriter::ensure_type_id(&mut *recorder.tracer, TypeKind::Raw, &class_name);
         return ValueRecord::Raw { r: text, type_id };
@@ -532,7 +532,7 @@ unsafe fn to_value(recorder: &mut Recorder, val: VALUE, depth: usize) -> ValueRe
     if !names.is_empty() {
         return struct_value(recorder, &class_name, &names, &vals, depth);
     }
-    let text = value_to_string(recorder, val).unwrap_or_default();
+    let text = value_to_string(recorder, val);
     let type_id = TraceWriter::ensure_type_id(&mut *recorder.tracer, TypeKind::Raw, &class_name);
     ValueRecord::Raw { r: text, type_id }
 }
@@ -751,7 +751,7 @@ unsafe extern "C" fn record_event_api(
         std::str::from_utf8(std::slice::from_raw_parts(ptr as *const u8, len)).unwrap_or("")
     };
     let line_num = rb_num2long(line) as i64;
-    let content_str = value_to_string(recorder, content).unwrap_or_default();
+    let content_str = value_to_string(recorder, content);
     record_event(&mut *recorder.tracer, path_slice, line_num, content_str);
     Qnil.into()
 }
@@ -864,9 +864,8 @@ unsafe extern "C" fn event_hook_raw(data: VALUE, arg: *mut rb_trace_arg_t) {
         TraceWriter::register_return(&mut *recorder.tracer, val_rec);
     } else if (ev & RUBY_EVENT_RAISE) != 0 {
         let exc = rb_tracearg_raised_exception(arg);
-        if let Some(msg) = value_to_string(recorder, exc) {
-            TraceWriter::register_special_event(&mut *recorder.tracer, EventLogKind::Error, &msg);
-        }
+        let msg = value_to_string(recorder, exc);
+        TraceWriter::register_special_event(&mut *recorder.tracer, EventLogKind::Error, &msg);
     }
 }