better reporting of bootstrap errors. would have prevented #1089.

Author: JeffBezanson

src/julia.expmap

@@ -181,6 +181,9 @@
     jl_get_current_task;
     jl_enter_handler;
     jl_exception_in_transit;
+    jl_errorexception_type;
+    jl_loaderror_type;
+    jl_backtrace_type;
     jl_show;
     jl_show_any;
     jl_print_symbol;

src/julia.h

@@ -342,10 +342,10 @@ extern jl_typename_t *jl_array_typename;
 extern jl_struct_type_t *jl_weakref_type;
 extern jl_struct_type_t *jl_ascii_string_type;
 extern jl_struct_type_t *jl_utf8_string_type;
-extern jl_struct_type_t *jl_errorexception_type;
+extern DLLEXPORT jl_struct_type_t *jl_errorexception_type;
 extern jl_struct_type_t *jl_typeerror_type;
-extern jl_struct_type_t *jl_loaderror_type;
-extern jl_struct_type_t *jl_backtrace_type;
+extern DLLEXPORT jl_struct_type_t *jl_loaderror_type;
+extern DLLEXPORT jl_struct_type_t *jl_backtrace_type;
 extern jl_value_t *jl_stackovf_exception;
 extern jl_value_t *jl_memory_exception;
 extern jl_value_t *jl_divbyzero_exception;

ui/repl.c

@@ -147,11 +147,28 @@ static int exec_program(void)
             //jl_lisp_prompt();
             //return 1;
             jl_value_t *errs = jl_stderr_obj();
+            jl_value_t *e = jl_exception_in_transit;
             if (errs != NULL) {
-                jl_show(jl_stderr_obj(), jl_exception_in_transit);
+                jl_show(jl_stderr_obj(), e);
             }
             else {
-                ios_printf(ios_stderr, "error during bootstrap\n");
+                while (1) {
+                    if (jl_typeof(e) == (jl_type_t*)jl_loaderror_type) {
+                        e = jl_fieldref(e, 2);
+                        // TODO: show file and line
+                    }
+                    else if (jl_typeof(e) == (jl_type_t*)jl_backtrace_type) {
+                        e = jl_fieldref(e, 0);
+                    }
+                    else break;
+                }
+                if (jl_typeof(e) == (jl_type_t*)jl_errorexception_type) {
+                    ios_printf(ios_stderr, "error during bootstrap: %s\n",
+                               jl_string_data(jl_fieldref(e,0)));
+                }
+                else {
+                    ios_printf(ios_stderr, "error during bootstrap\n");
+                }
             }
             ios_printf(ios_stderr, "\n");
             JL_EH_POP();