Fix error using Clang option '-stdlib=libc++'

[TotalNormal2]

Using Clang option "-stdlib=libc++" failed with:
cppcheck: error: unrecognized command line option: "--std=libc++"

[bruntib]

Thanks, it's a nice catch!

[ |=] matches any of the three characters between square brackets, because | is not a separator in this context. Also, the build_action.analyzer_option doesn't contain a space character if it starts with --std, because command line arguments are already split here.

What do you think of this regex?

Suggested change

	std_regex = re.compile("-?-std[ |=].*")
	std_regex = re.compile(r"-?-std\b.*")

[TotalNormal2]

Thank you for looking into this. You're right about the split and |.

I had to extend my regex knowledge first to understand your nice idea. I did some testing using an online regex evaluator (selected Python) and found:

• the pattern needs not to be at the start (solvable with ^)
• if a - (or any other special char) is following std anything afterwards will also be accepted

Example: ThisCanBeAnything-std-AlsoHere=AndMatch

I've tested other solutions like "^-(-std$)|(-?std=.*)" or "^--?std($)|(=.*)" (the latter still accepts -std c99) to avoid any undesired patterns. I compared them to "^-?-std\b.*" which requires only up to 10 steps to evaluate a string while the others require up to 30. On the downside it still accepts -std c99 or -std-Anything... but I vote for speed:

Suggested change

	std_regex = re.compile("-?-std[ |=].*")
	std_regex = re.compile(r"^-?-std\b.*")

Looking now into interesting_option (got that | from there) I'm wondering if it should be interesting_option = re.compile(r"^-[IUD].*") ?

[bruntib]

Thanks, it's a very nice analysis of the issue, it's good that we consider all corner cases. As a next step what do you think of this?

Suggested change

	std_regex = re.compile("-?-std[ |=].*")
	std_regex = re.compile(r"-?-std[\b=].*")

It means that after "std" it is either the end of the word or = follows. The ^is not necessarily needed, because function match() in line 109 finds the pattern at the beginning of the string.

Yes, the interesting_option should really be fixed to IUD instead of I|U|D.

[TotalNormal2]

It seems [\b] is matching backspace and [\b=] is matching backspace or = but not word boundary.
You're right about ^ not being required using match().

I've tested the following strings (1-3 are the correct ones) in an online-evaluator...

1. --std
2. -std=xxx
3. --std=xxx
4. -std
5. -stdlib=libc++
6. --stdä=hnlich
7. --std-not
8. -stdio=xxx
9. --stdio=xxx
10. -std-99
11. --std-C99
12. -std-99=xxx
13. --std-C99=xxx

...with these expressions (matching strings mentioned)

1. -(-std$|-?std=.*) matching: 1,2,3
2. -?-std($|=.*) matching: 1,2,3,4
3. -?-std(\b|=.*) matching: 1,2,3,4,(6),7,10,11,12,13 ; (6) had different results on different evaluators
4. -?-std[$=].* matching: 2,3
5. -?-std[\b=].* matching: 2,3

Only expression 1 has zero false-pos and false-neg.
I prefer avoiding \b because using - within a name is not complete out of the world but it's not a boundary (see 11-13).

[bruntib]

Wow, thanks, it's a very nice research and test cases :)
I start the tests and we can merge it. Thank you, well done!