Possible misuse of comma operator here

Question

I'm getting warnings in Xcode after updating to the recommended pod settings. The warning is

Possible misuse of comma operator here

with a suggested fix of

Cast expression to void to silence warning

The warnings occur in leveldb-library/db/c.cc at the start and limit keys:

void leveldb_compact_range(
    leveldb_t* db,
    const char* start_key, size_t start_key_len,
    const char* limit_key, size_t limit_key_len) {
  Slice a, b;
  db->rep->CompactRange(
      // Pass NULL Slice if corresponding "const char*" is NULL
      (start_key ? (a = Slice(start_key, start_key_len), &a) : NULL),
      (limit_key ? (b = Slice(limit_key, limit_key_len), &b) : NULL));
}

Has anyone else had the same or know what's causing it? I'm running Cocoapods 1.2.0.

If you want to disable this warning you can do it by [disabling the "Suspicious Commas" warning in your Build Settings](https://stackoverflow.com/a/37026478/111307) — bobobobo, Dec 16 '20 at 22:11

score 4 · Accepted Answer · answered Oct 31 '17 at 19:06

4

leveldb now builds without warnings after a pod update to version 1.20 of the leveldb-library CocoaPod.

answered Oct 31 '17 at 19:06

Paul Beusterien

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thanks for the heads up! The update installed with 16 new errors but after a subsequent clean, all errors and warnings are gone – Shane O'Seasnain Oct 31 '17 at 21:54
One small thing the upgrade numbering for the database seems to go backwards... Installing FirebaseDatabase 4.1.0 (was 4.1.1) – Shane O'Seasnain Oct 31 '17 at 21:57
@ShaneO'Seasnain The version shouldn't go backwards. Check your Podfile.lock, pod deintegrate, etc. If you're still seeing and can make a repro, please report to https://github.com/firebase/firebase-ios-sdk/issues – Paul Beusterien Oct 31 '17 at 22:22
Ok. Thanks for the feedback – Shane O'Seasnain Oct 31 '17 at 22:24

score 4 · Answer 2 · answered Jul 11 '19 at 05:07

4

This solution works for me.

Code:

 if (++keyIndexValue == [self.str length])
    keyIndexValue = 0, keyPtr = keyData;

I've solved it by splitting the statements over multiple lines within the "if" condition:

"If at end of key data, reset count and set key pointer back to start of key value"

if (++keyIndexValue == [self.str length])
{
   keyIndexValue = 0;
   keyPtr = keyData;
}

answered Jul 11 '19 at 05:07

Gajendra K Chauhan

3,387
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It seems this is what Apple wanted, but I have to say they shouldn't force us to add { squiggly brackets } around an if-block where we knew what we were doing – bobobobo Dec 16 '20 at 21:52
The other way to do it (which looks really messy) would be to cast the left operand to `operator,` to void, like this: `(void)(keyIndexValue = 0), keyPtr = keyData;` – bobobobo Dec 16 '20 at 21:59

score 1 · Answer 3 · answered Oct 23 '17 at 18:24

1

We are aware of the warning, we'll update the version once the leveldb fixes the issue. For now you can ignore the warnings.

answered Oct 23 '17 at 18:24

Ibrahim Ulukaya

12,767
1
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Ok. Thanks for the heads up – Shane O'Seasnain Oct 23 '17 at 18:26

Possible misuse of comma operator here

3 Answers3