0000477: Infinite recursion through exception handlers

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Project

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Date Submitted

Last Update

0000477

mercury

Feature Request

public

2019-04-17 16:51

2019-04-20 14:58

Reporter

juliensf

Assigned To

Priority

normal

Severity

minor

Reproducibility

have not tried

Status

resolved

Resolution

fixed

Product Version

Target Version

Fixed in Version

Summary

0000477: Infinite recursion through exception handlers

Description

Code such as the following is may be worth a warning.

:- pred reconstruct_route(logger::in, jscenario::in, jsolution::out)
    is cc_multi.

reconstruct_route(Log, JScenario, JSolution) :-
    ( try []
        reconstruct_route(Log, JScenario, JSolution0)
    then
        JSolution = JSolution0
    catch_any Excp ->
        trace [io(!IO)] (
            Msg = "Exception during route reconstruction: " ++ string(Excp),
            slf4j.error(Log, Msg, !IO)
        ),
        JSolution = null_jsolution
    ).

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Attached Files

bug477.m (871 bytes) 2019-04-18 00:37

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Notes
~0001023 zs (developer) 2019-04-17 22:28	Can you please add a full test case?

~0001029 juliensf (administrator) 2019-04-18 00:37	There's a cut-down version that exhibits the behaviour attached. The current check carried out by simplify for recursive calls with the same input arguments doesn't look through higher-order calls since in general it cannot. I suspect it may be worth making a special case of try/2 (and its syntax sugared form) since wrapping an exception handler around the entry point to a Mercury program that is called from a foreign language application (which is the original setting for this) is not uncommon. Nor unfortunately is forgetting to use the correct predicate name inside the try goal which is what I did :-(

~0001038 zs (developer) 2019-04-20 14:58	Feature implemented 2019 April 20.

Notes

Date Modified	Username	Field	Change
Issue History
2019-04-17 16:51	juliensf	New Issue
2019-04-17 22:28	zs	Note Added: 0001023
2019-04-18 00:37	juliensf	File Added: bug477.m
2019-04-18 00:37	juliensf	Note Added: 0001029
2019-04-20 08:57	zs	Assigned To	=> zs
2019-04-20 08:57	zs	Status	new => assigned
2019-04-20 14:58	zs	Status	assigned => resolved
2019-04-20 14:58	zs	Resolution	open => fixed
2019-04-20 14:58	zs	Note Added: 0001038

Issue History