795213 - clang's -Wtautological-constant-out-of-range-compare warns on prnetdb.c

Status: RESOLVED FIXED

(NSPR :: NSPR, defect, P2)

Description

[thakis]

Attachment: nspr.patch

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.6 Safari/537.11

Steps to reproduce:

I built nspr with a very recent version of clang (r164143 or newer).


Actual results:

../../third_party/nss/mozilla/nsprpub/pr/src/misc/prnetdb.c:2081:16: error: comparison of constant 3 with expression of type 'PRStatus' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
        if (rv == EAI_BADFLAGS && (hints.ai_flags & AI_ADDRCONFIG)) {
            ~~ ^  ~~~~~~~~~~~~
1 error generated.


Expected results:

No warning.

The warning is correct, GETADDRINFO(), which is declared further up in the file and returns int, not PRStatus. Since rv is currently PRStatus, it can only be PR_FAILURE = -1 or PR_SUCCESS = 0, never EAI_BADFLAGS = 3.

rv is only used for the return value of GETADDRINFO(), so the fix is to change it to int (see attached patch).

Comment 1

[Wan-Teh Chang]

Thank you for the patch!

Patch checked in on the NSPR trunk (NSPR 4.9.3).

Checking in prnetdb.c;
/cvsroot/mozilla/nsprpub/pr/src/misc/prnetdb.c,v  <--  prnetdb.c
new revision: 3.68; previous revision: 3.67
done