1294619 - Enable the no-ex-assign rule for eslint

Status: RESOLVED FIXED

(Toolkit :: General, defect)

Description

[Jared Wein [:jaws] (please needinfo? me)]

no-ex-assign: disallow reassigning exceptions in catch clauses

If a catch clause in a try statement accidentally (or purposely) assigns another value to the exception parameter, it impossible to refer to the error from that point on. Since there is no arguments object to offer alternative access to this data, assignment of the parameter is absolutely destructive.

Paolo, I would like to enable this rule but it is currently failing due to two lines in DownloadCore.jsm:

https://hg.mozilla.org/mozilla-central/file/ab1d29e62ee4/toolkit/components/jsdownloads/src/DownloadCore.jsm#l526

and 

https://hg.mozilla.org/mozilla-central/file/ab1d29e62ee4/toolkit/components/jsdownloads/src/DownloadCore.jsm#l539

Can you give some advice on how you would like this code refactored?

Comment 1

[:Paolo Amadini]

The simple approach will work for now.

In the future, the refactoring in bug 1265329 might result in us doing less work in the catch block.

Comment 2

[:Paolo Amadini]

Attachment: Bug 1294619 - Update jsdownloads code to enable the no-ex-assign rule for ESLint.

Review commit: https://reviewboard.mozilla.org/r/71168/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/71168/

Comment 3

[Jared Wein [:jaws] (please needinfo? me)]

Comment on attachment 8780461 [details]
Bug 1294619 - Update jsdownloads code to enable the no-ex-assign rule for ESLint.

https://reviewboard.mozilla.org/r/71168/#review68748

Thanks! I'll land this.

Comment 4

[Jared Wein [:jaws] (please needinfo? me)]

https://hg.mozilla.org/integration/fx-team/rev/8725f14625e0c87776f9acf66e6712ceca301000
Bug 1294619 - Update jsdownloads code to enable the no-ex-assign rule for ESLint. r=jaws

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/8725f14625e0