1568869 - Preferences can be defined multiple times in StatcPrefList.yaml if they have different types

Status: RESOLVED FIXED

(Core :: Preferences: Backend, defect)

Description

[Tom Ritter [:tjr] (OOTO until April)]

I hadn't noticed that these were already in the .yaml file:
https://searchfox.org/mozilla-central/rev/40e889be8ff926e32f7567957f4c316f14f6fbef/modules/libpref/init/StaticPrefList.yaml#5742-5751

I had added them myself, without any error. Then when I changed my added ones' type to match the original; and I (finally) got build errors about a duplicate.

(It's possible the mirror type also needs to be the different.)

Example: this build uses this file

Comment 1

[Nicholas Nethercote [inactive]]

Good catch, thank you for the report. The mirror value is key here.

• The generated C++ code will fail to compile in these pairings: always/always, always/once, once/once.
• The C++ code will compile ok in these pairings: always/never, once/never, never/never.

I'm not sure what the runtime behaviour will be in those cases, and I don't want to work it out :) I will change generate_static_pref_list.yaml to detect duplicates.

Comment 2

[Nicholas Nethercote [inactive]]

Attachment: Bug 1568869 - Disallow double definitions in StaticPrefList.yaml. r=glandium

Some double definitions would have caused C++ compile errors, but some would
not, and I'm not even sure what the runtime behaviour would have been in those
latter cases...

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e2e11c1cb2e2
Disallow double definitions in StaticPrefList.yaml. r=glandium

Comment 4

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/e2e11c1cb2e2