Validate fixed-size strings

src/Introspection.cake

@@ -248,6 +248,9 @@
 
       (var field-type-element-size (<> (in std vector) Token))
       (cond
+        ;; A somewhat special case: repurpose element-size where a fixed char array is one element
+        ((= 0 (strcmp determined-type-string "introspect-type-fixed-size-string"))
+         (tokenize-push field-type-element-size (token-splice (+ 2 core-type-token))))
         (type-is-string
          (tokenize-push field-type-element-size (sizeof char)))
         (is-override-pointer ;; Assume pointers are the same size
@@ -833,8 +836,18 @@
     ((= (path field > type) introspect-type-fixed-size-string)
      (var str-write (* char)
        (offset-pointer-to-type struct-out value-offset (* char)))
-     ;; TODO Validate size
-     (strncpy str-write in-string value-length))
+     (when (>= value-length (path field > element-size))
+       (fprintf stderr "error: struct %s field %s has length %d, which cannot fit value of length %d" \
+                " and a null terminator. Value: "
+                (path struct-metadata > name)
+                (path field > name)
+                (type-cast (path field > element-size) int)
+                (type-cast value-length int))
+       (print-string-range in-string (+ in-string value-length) true)
+       (return false))
+     (strncpy str-write in-string value-length)
+     ;; Ensure null terminator gets written
+     (set (at value-length str-write) 0))
     ((= (path field > type) introspect-type-string)
      ;; Don't allocate for empty strings
      (unless value-length

test/Errors.cakedata

@@ -1,5 +1,5 @@
 (my-struct :name "Test struct"
-           :other-name "Other name"
+           :other-name "--------------------------------"
            :yet-another-name "Another name"
            :optional-name ""
            :value 42