"variable = variable = value" -> should issue a warning

[Sven Strickroth]

In a codebase I've spotted variable assignments in the form of "variable = variable = value" (e.g., "m_bA = m_bA = 2;"). It would be nice if cppcheck would also detect such double assignments.

[Daniel Marjamäki]

Could you elaborate a little.

int x;

void f() {
     x = x = 2;
}

Cppcheck output:

$ ./cppcheck --enable=style 1.c
Checking 1.c ...
1.c:5:5: warning: Redundant assignment of 'x' to itself. [selfAssignment]
  x = x = 2;
    ^

[Sven Strickroth]

These cases (https://gitlab.com/tortoisegit/tortoisegit/commit/9051ad7a35165f2f45ecdcc2220c914998a655de) were not spotted by cppcheck (GUI).

[Daniel Marjamäki]

hmm... I do not get these warnings neither... I think this is a real problem in Cppcheck. Thanks!

[Daniel Marjamäki]

The first false negative seems to be related to the BEGIN_MESSAGE_MAP ... END_MESSAGE_MAP

Cppcheck does not know what that is.. and it is not defined anywhere in the repo.

hmm.. .you are supposed to get a information message if there is such unknown macro! So you can fix it in some way.

I have created this ticket:
https://trac.cppcheck.net/ticket/9354

[versat]

@Sven The ticket http://trac.cppcheck.net/ticket/9354 has been resolved.
The unknown macros will now be reported and there is now a configuration for the MFC (mfc.cfg).
I have added another configuration for the Microsoft ATL (microsoft_atl.cfg) since Cppcheck found corresponding macros that were also missing a configuration for analyzing TortoiseGit.
Several false positives and other issues found by analyzing TortoiseGit were also fixed in the Windows configuration of Cppcheck.
So the results should be a bit better now.

BTW: I love TortoiseGit and use it very often. Thanks for such a great tool.

[Allan Braun]

Where can I download mfc.cfg

[Allan Braun]

I just installed the latest version 2.0
For a MS-Windows Visual Studio project
I still get the error
There is an unknown macro here somewhere. Configuration is required. If BEGIN_MESSAGE_MAP is a macro then please configure it.

[Allan Braun]

I just installed version 2.1
Still same problem
How do I work around this?

[Daniel Marjamäki]

You asked how to download mfc.cfg. Sorry that I did not reply. If you still wonder; feel free to download this file: https://github.com/danmar/cppcheck/raw/2.1/cfg/mfc.cfg

all cfg files:
https://github.com/danmar/cppcheck/tree/2.1/cfg

I believe the intention is to distribute all of the cfg files except "cppcheck-internal.cfg". So we need to review this.

[Daniel Marjamäki]

I checked the tortoisegit code and it seems we have a couple of problems. With the mfc.cfg I do not get unknown macro warnings about BEGIN_MESSAGE_MAP but I do see other problems that we should fix in Cppcheck.

[Allan Braun]

Hi Daniel
I got the mfc.cfg
How do I load this file?
I am using the GUI

[Daniel Marjamäki]

if you put a cfg file in the same folder as your <foo>.cppcheck project file then it should be shown in the list in the GUI.

[Allan Braun]

There should be a way to load a cfg file from the GUI

---

From: "Daniel Marjamäki" danielmarjamaki@users.sourceforge.net
Sent: Sunday, June 28, 2020 2:06 AM
To: "[cppcheck:discussion]" general@discussion.cppcheck.p.re.sourceforge.net
Subject: [cppcheck:discussion] "variable = variable = value" -> should issue a warning

if you put a cfg file in the same folder as your <foo>.cppcheck project file then it should be shown in the list in the GUI.</foo>

"variable = variable = value" -> should issue a warning

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[Daniel Marjamäki]

please see the list in the project file dialog.