836345 - nsAutoCompleteController.cpp:1070:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

Status: RESOLVED FIXED

(Toolkit :: Autocomplete, defect)

Description

[Daniel Holbert [:dholbert]]

{
toolkit/components/autocomplete/nsAutoCompleteController.cpp: In member function ‘void nsAutoCompleteController::AfterSearches()’:
toolkit/components/autocomplete/nsAutoCompleteController.cpp:1070:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

toolkit/components/autocomplete/nsAutoCompleteController.cpp: In member function ‘nsresult nsAutoCompleteController::StartSearches()’:
toolkit/components/autocomplete/nsAutoCompleteController.cpp:1121:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
}

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: fix

Comment 2

[Daniel Holbert [:dholbert]]

Normally I'd want to add some range-checks before blindly converting an int32_t to a uint32_t, but I don't think it's worth it here, because:

 (a) the contextual code in nsAutoCompleteController.cpp already stores the Count() result in an unsigned value in several places already. (w/out range checks)

 (b) Under the hood, nsCOMArray::Count()'s implementation[1] actually returns a uint32_t, but it just stuffs it into an int32_t (for historical reasons I assume).
 
[1] https://mxr.mozilla.org/mozilla-central/source/xpcom/glue/nsCOMArray.h#62

Comment 3

[Daniel Holbert [:dholbert]]

Attachment: fix v2

oops, prev fix didn't compile due to missing close-paren. Fixed here.

Comment 4

[Mounir Lamouri (:mounir)]

Comment on attachment 708190 [details] [diff] [review]
fix v2

Review of attachment 708190 [details] [diff] [review]:
-----------------------------------------------------------------

r=me with casting made with static_cast<> instead of uint32_t().

Comment 5

[Daniel Holbert [:dholbert]]

Switched to static_cast and pushed:
 https://hg.mozilla.org/integration/mozilla-inbound/rev/5e57a1b8f7b4

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/5e57a1b8f7b4