367377 – false positive for 'no return from non-void function' where a switch has a default case

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Bug 367377 - false positive for 'no return from non-void function' where a switch has a default case

Summary: false positive for 'no return from non-void function' where a switch has a de...

Status:	RESOLVED FIXED

Alias:	None

Product:	CDT
Classification:	Tools
Component:	cdt-codan (show other bugs)
Version:	8.0
Hardware:	PC Linux

Importance:	P3 normal with 1 vote (vote)
Target Milestone:	---
Assignee:	CDT Codan Inbox
QA Contact:	Elena Laskavaia

URL:
Whiteboard:
Keywords:

Depends on:
Blocks:

Reported:	2011-12-21 18:42 EST by Matt Hargett
Modified:	2016-12-22 18:48 EST (History)
CC List:	5 users (show)

See Also:

Attachments
Code Analysis Settings (126.38 KB, image/jpeg) 2012-01-28 10:37 EST, Saifudheen AA	no flags	Details
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Description Matt Hargett

2011-12-21 18:42:34 EST

Build Identifier: Build id: 20111215-0110

inline const char *ICAP_Scan_status_to_string(ICAP_Scan_status iss)
{
    switch (iss)
    {
    case ISS_NOT_SCANNED:
        return "ICAP_COMMUNICATION_ERROR";                    
    case ISS_NO_MODIFICATION:
        return "ICAP_NO_MODIFICATION";                        
    case ISS_REPLACEMENT:
        return "ICAP_REPLACED";                                
    case ISS_SCAN_IN_PROGRESS:
        return "ISS_SCAN_IN_PROGRESS";

    case ISS_CORRUPT_UNSCANNED_OBJECT:
        return "ISS_CORRUPT_UNSCANNED_OBJECT";

    default:
        return "unknown";
    }
}

Here, this switch doesn't cover all of the cases in the enum -- the default
case isn't dead code (not that I think CODAN is thinking *that* deeply about it
;)). All paths return a value, so this is a false positive.

Created in a new bug, as requested in comments to bug #350168.

Reproducible: Always

Comment 1 Saifudheen AA

2012-01-28 10:37:15 EST

Created attachment 210231 [details]
Code Analysis Settings

Comment 2 Saifudheen AA

2012-01-28 10:40:00 EST

I do have the same problem.

Eclipse IDE for C/C++ Developers

Version: Indigo Service Release 1
Build id: 20110916-0149

Comment 3 Nathan Ridge

2012-11-17 17:25:59 EST

The given test case is incomplete because it does not include the definition of ICAP_Scan_status.

I tried to reproduce the error by making up a definition for it, adding some other values in the enumeration beyond what is used in the switch statement. However, I am getting no warning with this with Juno:


enum ICAP_Scan_status 
{
    ISS_NOT_SCANNED, 
    ISS_NO_MODIFICATION, 
    ISS_REPLACEMENT, 
    ISS_SCAN_IN_PROGRESS, 
    ISS_CORRUPT_UNSCANNED_OBJECT, 
    SOME_OTHER_VALUE1,
    SOME_OTHER_VALUE2
};

inline const char *ICAP_Scan_status_to_string(ICAP_Scan_status iss)
{
    switch (iss)
    {
    case ISS_NOT_SCANNED:
        return "ICAP_COMMUNICATION_ERROR";                    
    case ISS_NO_MODIFICATION:
        return "ICAP_NO_MODIFICATION";                        
    case ISS_REPLACEMENT:
        return "ICAP_REPLACED";                                
    case ISS_SCAN_IN_PROGRESS:
        return "ISS_SCAN_IN_PROGRESS";

    case ISS_CORRUPT_UNSCANNED_OBJECT:
        return "ISS_CORRUPT_UNSCANNED_OBJECT";

    default:
        return "unknown";
    }
}


Do you still see a warning in Juno? If so, could you please post a complete testcase?

Comment 4 Alexey Alexey

2015-04-22 09:08:43 EDT

Reproduced in Luna (4.4.0). Example:

enum
{
  OK = 100,
  WARNINGS = 200,  
};

int TestCase(int completionStatus)
{
  switch (completionStatus)
  {
  case OK: return 0;
  case WARNINGS: return 1;
  default: return 2;
  };
}

Comment 5 Nathan Ridge

2015-05-12 17:42:20 EDT

I can reproduce the warning in comment 4 in 4.4.0, but not in a recent nightly build, suggesting that the problem was fixed (possibly in bug 455828).

Comment 6 Alexey Alexey

2015-07-01 04:01:55 EDT

Checked in Mars. Bug fixed.

Comment 7 Nathan Ridge

2016-12-22 18:48:22 EST

Closing per comment 6.