188640 - nsEmbedGlobalHistory.cpp: enumWriteEntryIfUnwritten can test NS_SUCCEEDED(rv) on an uninitialized rv!

Status: VERIFIED FIXED

(Core Graveyard :: Embedding: APIs, defect)

Description

[Aleksey Nogin]

After embedding/lite became a part of the build, a new "uninitialized" warning
appeared on brad TBox:

+embedding/lite/nsEmbedGlobalHistory.cpp:538
+ `nsresult rv' might be used uninitialized in this function

The code in question (end of enumWriteEntryIfUnwritten function) looks as follows:

   nsresult rv;
   if (!entry->GetIsWritten())
     rv = writeEntry(outStm, stringKey, entry);
     
   return NS_SUCCEEDED(rv) ? PR_TRUE : PR_FALSE;

Indeed, when the "if" condition is false, the function will return a random
value (depending on memory contents in an uninitialized nsresult).

P.S. See also bugs 59652 and 179819. Bug 59652 is the meta-bug tracking the
fight against these (potentially very nasty) warnings and bug 179819 wants such
warnings turned into compilation errors.

Comment 1

[Conrad Carlen (not reading bugmail)]

Fixed.

Comment 2

[Aleksey Nogin]

V, the warning has disappeared from TBox