1236413 - Suppress -Wimplicit-fallthrough warning in third-party code mfbt/decimal/

Status: RESOLVED FIXED

(Core :: MFBT, defect)

Description

[Chris Peterson [:cpeterson]]

Attachment: Decimal_Wno-implicit-fallthrough.patch

clang's -Wimplicit-fallthrough warnings (not yet enabled in mozilla-central) warn about switch cases that fall through without a break or return statement. MOZ_FALLTHROUGH (bug 1215411) is an annotation to suppress -Wimplicit-fallthrough warnings where the fallthrough is intentional.

Decimal.cpp is third-party code imported from Blink, so we can either suppress the warning in moz.build or apply a local patch (adding a MOZ_FALLTHROUGH annotation).

This -Wimplicit-fallthrough warning has actually been fixed in Blink's upstream Decimal.cpp. I tried updating our Decimal.cpp snapshot and reapplying our in-tree patches, but there were some merge conflicts from upstream changes I didn't understand well enough to resolve confidently.

mfbt/decimal/Decimal.cpp:762:9 [-Wimplicit-fallthrough] unannotated fall-through between switch labels

Comment 1

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/deba095103f3

Comment 2

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/deba095103f3