Exception#detailed_message is added

Also, the default error printer and Exception#full_message use the
method instead of `Exception#message` to get the message string.

`Exception#detailed_message` calls `Exception#message`, decorates and
returns the result. It adds some escape sequences to highlight, and the
class name of the exception to the end of the first line of the message.

[Feature #18370]

1 files changed, 53 insertions, 4 deletions

diff --git a/error.c b/error.c
index 8f9e21dbb5..be4c37cbac 100644
--- a/error.c
+++ b/error.c
@@ -1122,7 +1122,7 @@ static VALUE rb_eNOERROR;
 
 ID ruby_static_id_cause;
 #define id_cause ruby_static_id_cause
-static ID id_message, id_backtrace;
+static ID id_message, id_detailed_message, id_backtrace;
 static ID id_key, id_matchee, id_args, id_Errno, id_errno, id_i_path;
 static ID id_receiver, id_recv, id_iseq, id_local_variables;
 static ID id_private_call_p, id_top, id_bottom;
@@ -1224,7 +1224,7 @@ exc_to_s(VALUE exc)
 }
 
 /* FIXME: Include eval_error.c */
-void rb_error_write(VALUE errinfo, VALUE emesg, VALUE errat, VALUE str, VALUE highlight, VALUE reverse);
+void rb_error_write(VALUE errinfo, VALUE emesg, VALUE errat, VALUE str, VALUE opt, VALUE highlight, VALUE reverse);
 
 VALUE
 rb_get_message(VALUE exc)
@@ -1235,6 +1235,21 @@ rb_get_message(VALUE exc)
     return e;
 }
 
+VALUE
+rb_get_detailed_message(VALUE exc, VALUE opt)
+{
+    VALUE e;
+    if (NIL_P(opt)) {
+        e = rb_check_funcall(exc, id_detailed_message, 0, 0);
+    }
+    else {
+        e = rb_check_funcall_kw(exc, id_detailed_message, 1, &opt, 1);
+    }
+    if (e == Qundef) return Qnil;
+    if (!RB_TYPE_P(e, T_STRING)) e = rb_check_string_type(e);
+    return e;
+}
+
 /*
  * call-seq:
  *    Exception.to_tty?   ->  true or false
@@ -1332,9 +1347,9 @@ exc_full_message(int argc, VALUE *argv, VALUE exc)
 
     str = rb_str_new2("");
     errat = rb_get_backtrace(exc);
-    emesg = rb_get_message(exc);
+    emesg = rb_get_detailed_message(exc, opt);
 
-    rb_error_write(exc, emesg, errat, str, highlight, order);
+    rb_error_write(exc, emesg, errat, str, opt, highlight, order);
     return str;
 }
 
@@ -1354,6 +1369,38 @@ exc_message(VALUE exc)
 
 /*
  * call-seq:
+ *   exception.detailed_message(highlight: bool, **opt)   ->  string
+ *
+ * Processes a string returned by #message.
+ *
+ * It may add the class name of the exception to the end of the first line.
+ * Also, when +highlight+ keyword is true, it adds ANSI escape sequences to
+ * make the message bold.
+ *
+ * If you override this method, it must be tolerant for unknown keyword
+ * arguments. All keyword arguments passed to #full_message are delegated
+ * to this method.
+ *
+ * This method is overridden by did_you_mean and error_highlight to add
+ * their information.
+ */
+
+static VALUE
+exc_detailed_message(int argc, VALUE *argv, VALUE exc)
+{
+    VALUE opt;
+
+    rb_scan_args(argc, argv, "0:", &opt);
+
+    VALUE highlight = check_highlight_keyword(opt);
+
+    extern VALUE rb_decorate_message(const VALUE eclass, const VALUE emesg, int highlight);
+
+    return rb_decorate_message(CLASS_OF(exc), rb_get_message(exc), highlight);
+}
+
+/*
+ * call-seq:
  *   exception.inspect   -> string
  *
  * Return this exception's class name and message.
@@ -2908,6 +2955,7 @@ Init_Exception(void)
     rb_define_method(rb_eException, "==", exc_equal, 1);
     rb_define_method(rb_eException, "to_s", exc_to_s, 0);
     rb_define_method(rb_eException, "message", exc_message, 0);
+    rb_define_method(rb_eException, "detailed_message", exc_detailed_message, -1);
     rb_define_method(rb_eException, "full_message", exc_full_message, -1);
     rb_define_method(rb_eException, "inspect", exc_inspect, 0);
     rb_define_method(rb_eException, "backtrace", exc_backtrace, 0);
@@ -2995,6 +3043,7 @@ Init_Exception(void)
 
     id_cause = rb_intern_const("cause");
     id_message = rb_intern_const("message");
+    id_detailed_message = rb_intern_const("detailed_message");
     id_backtrace = rb_intern_const("backtrace");
     id_key = rb_intern_const("key");
     id_matchee = rb_intern_const("matchee");