1419654 - Prevent possible pref default/user value type mismatches

Status: RESOLVED FIXED

(Core :: Preferences: Backend, enhancement)

Description

[Nicholas Nethercote [inactive]]

Currently, you can create a pref that only has a user value, and then later
give it a default value with a different type. The entire pref is then recorded
as having this second type. This causes problems later when interpreting the
user value.

Comment 1

[Nicholas Nethercote [inactive]]

Attachment: Bug 1419654 - Prevent possible pref default/user value type mismatches.

Currently, you can create a pref that only has a user value, and then later
give it a default value with a different type. The entire pref is then recorded
as having this second type. This causes problems later when interpreting the
user value.

This patch makes SetValue() fail if it tries to set a default value whose type
differs from an existing user value. It also expands an existing test to cover
this case and some similar ones.

Review commit: https://reviewboard.mozilla.org/r/201898/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/201898/

Comment 2

[Mike Hommey [:glandium]]

Comment on attachment 8930805 [details]
Bug 1419654 - Prevent possible pref default/user value type mismatches.

https://reviewboard.mozilla.org/r/201898/#review207252

Comment 3

[Nicholas Nethercote [inactive]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/4c24fa3a323b29d2a64188f83412eaa89a26a231
Bug 1419654 - Prevent possible pref default/user value type mismatches. r=glandium

Comment 4

[Arthur Iakab [arthur_iakab]]

https://hg.mozilla.org/mozilla-central/rev/4c24fa3a323b