0003214: Exception printing bug?

Notes
(0003089) administrator (administrator) 2004-11-18 10:19	> there seems to be a bug printing exceptions. First of all, the > implementations of the module Printexc and of byterun/printexc.c don't > match. E.g.: > exception E of (int * string) > [...] Right, exceptions that take a tuple of arguments are special-cased differently in Printexc and in the runtime system. Note however that the code in the runtime system sometimes goes too far, e.g. exception E of string list let () = raise (E ["foo"]) prints Fatal error: exception Foo.E("foo", 0) so it's unclear we want to reproduce this bug in Printexc... Also, "exception E of int * string" would work fine in both printers. > In addition to this we have also complicated applications that sometimes > print out exceptions containing only one string argument without the > contents of the string, e.g.: > > exception SomeException of string > > Leads to the exception string: > > SomeException (_) > > instead of: > > SomeException ("explanation of error") > > I haven't yet managed to reproduce this error reliably. Maybe you have > an idea why this can happen? How is the printing done? At the toplevel, via Printexc or by the runtime system? The only case that I know of is at the toplevel: # exception E of string list;; exception E of string list # let f () = raise (E ["hello"]);; val f : unit -> 'a = <fun> # exception E of int;; exception E of int # f ();; Exception: E _. It's due to the shadowing of the declaration of E. But even in this case, exceptions that carry a string are special-cased and print correctly: # exception E of string;; exception E of string # let f () = raise (E "hello");; val f : unit -> 'a = <fun> # exception E of int;; exception E of int # f ();; Exception: E "hello". Best wishes, - Xavier Leroy

(0003090) administrator (administrator) 2004-11-22 21:09	On Thu, 18 Nov 2004, Xavier Leroy wrote: > > In addition to this we have also complicated applications that sometimes > > print out exceptions containing only one string argument without the > > contents of the string, e.g.: > > > > exception SomeException of string > > > > Leads to the exception string: > > > > SomeException (_) > > > > instead of: > > > > SomeException ("explanation of error") > > > > I haven't yet managed to reproduce this error reliably. Maybe you have > > an idea why this can happen? > > How is the printing done? At the toplevel, via Printexc or by the > runtime system? The only case that I know of is at the toplevel: [snip] > It's due to the shadowing of the declaration of E. But even in this > case, exceptions that carry a string are special-cased and print > correctly: [snip] It's actually also Failure-exceptions which are sometimes printed without argument. It happens very rarely, I hope we will be able to reliably reproduce this problem in a short code snippet. Thanks anyway for investigating this. Best regards, Markus

(0003091) administrator (administrator) 2005-01-31 17:28	Waiting for repro case.

(0004412) gerd (reporter) 2008-01-11 16:33	I don't have a repro case for Failure, but for Invalid_argument. Separately reported as 0004476.

(0004424) doligez (administrator) 2008-01-22 12:03	fixed in 3.10.2+dev2

Issue History
Date Modified	Username	Field	Change
2005-11-18 10:14	administrator	New Issue
2008-01-11 16:33	gerd	Note Added: 0004412
2008-01-17 17:08	doligez	Relationship added	related to 0004476
2008-01-22 12:03	doligez	Note Added: 0004424
2008-01-22 12:03	doligez	Status	acknowledged => closed
2008-01-22 12:03	doligez	Resolution	unable to reproduce => fixed
2008-01-22 12:03	doligez	Fixed in Version	=> 3.10+dev
2008-01-22 12:03	doligez	Description Updated
2017-02-23 16:36	doligez	Category	OCaml general => -OCaml general
2017-03-03 17:55	doligez	Category	-OCaml general => -(deprecated) general
2017-03-03 18:01	doligez	Category	-(deprecated) general => ~deprecated (was: OCaml general)
2017-03-06 17:04	doligez	Category	~deprecated (was: OCaml general) => ~DO NOT USE (was: OCaml general)