Improve error for array size with a '<' character

Previously we'd fail an assertion and dump core, which isn't nice:

Bad template type passed to SwigType_remember: a(std::numeric_limits< unsigned char >::max()).unsigned char
swig: ../../Source/Swig/typesys.c:1709: SwigType_remember_clientdata: Assertion `0' failed.
Aborted (core dumped)

We also now know that this situation can be triggered by particular
user inputs, so an assertion is not an appropriate check anyway.

Now we report an error and exit with non-zero status:

:1: Error: Array size expressions containing a '<' character not fully supported

The `:1:` part isn't ideal but happens because the SwigType doesn't seem
to have file:line information.

See #2486.

1 files changed, 7 insertions, 4 deletions

diff --git a/Source/Swig/typesys.c b/Source/Swig/typesys.c
index fc2224bf5..1d108dbde 100644
--- a/Source/Swig/typesys.c
+++ b/Source/Swig/typesys.c
@@ -1700,10 +1700,13 @@ void SwigType_remember_clientdata(const SwigType *t, const_String_or_char_ptr cl
   if (t) {
     char *ct = Char(t);
     const char *lt = strchr(ct, '<');
-    /* Allow for `<<` operator in constant expression for array size. */
-    if (lt && lt[1] != '(' && lt[1] != '<') {
-      Printf(stdout, "Bad template type passed to SwigType_remember: %s\n", t);
-      assert(0);
+    if (lt && lt[1] != '(') {
+      /* We special case `<<` above, but most cases aren't handled, for example:
+       *
+       * unsigned char myarray[std::numeric_limits<unsigned char>::max()]; // #2486
+       */
+      Swig_error(Getfile(t), Getline(t), "Array size expressions containing a '<' character not fully supported");
+      Exit(EXIT_FAILURE);
     }
   }