fix #5591: Add check for meaningless comma operator in if statement, misplaced ')' #7406
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Thanks for your contribution. Note that these issues seem to be diagnosed already by current compilers. |
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Hi CHR, many thanks for your comments, and I have updated the commit. But there is a failed case tested on the github for the commit, that seems not the problem of the committed code. Seems the network traffic caused a overtime. But I am not sure. Do you know how to trigger the checks to run again? Thanks a lot! |
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The macos runners can be very slow sometimes. I have restarted the failing run. |
| @@ -204,6 +204,7 @@ LIBOBJ = $(libcppdir)/valueflow.o \ | |||
| $(libcppdir)/checkleakautovar.o \ | |||
| $(libcppdir)/checkmemoryleak.o \ | |||
| $(libcppdir)/checknullpointer.o \ | |||
| $(libcppdir)/checkoperatorcomma.o \ | |||
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I don't want that we have files with just 1 checker. With this filename it's hard to see that more checkers would be added later. I suggest that your checker is added in checkother instead.
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or make the name more generic so more checkers can be added in it.
| const Token * parent = tok->astParent(); | ||
| if (parent && (Token::simpleMatch(parent->previous(), "if (") || | ||
| Token::simpleMatch(parent->previous(), "while ("))) { | ||
| assertWithSuspiciousCommaError(tok); |
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it looks strange to me that assertWithSuspiciousComma is reported when there is no assert.
| parent = parent->astParent(); | ||
| if (Token::simpleMatch(parent->previous(), "for (")) { | ||
| if (tok->index() < tok->astParent()->index()) { | ||
| assertWithSuspiciousCommaError(tok); |
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I have the feeling this could be noisy. Maybe you want to increment two variables in the third expression and then a comma seems natural.
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the PR description says that you want to detect: well yes that looks like a possible bug. there seems to be misplaced parenthesis but I fear your checker is much more verbose. you warn whenever there is a comma in a if/while. no matter if there are function calls. If the condition says: I agree the code looks weird.. but it's not a likely misplaced parenthesis and I am not convinced that the comma is a bug. It looks intentional. |
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I also want to point out that misra has a rule that forbids comma operators. But I still feel sympathy for this checker if we make it more specific and it can detect actual bugs and not just warn about random comma operators. |
https://trac.cppcheck.net/ticket/5591
Description:
int f2(int, int = 0) {....}
void f()
{
if(f2(0), 0) //actually mean f2(0, 0)
{
....
}
}