make sure the language for a Token/TokenList is always determined

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Requires #5848 to be merged first and is a prerequisite for #5724 and #5725.

Several of the test Clang AST dumps have no filename specified which causes the language not be be determined. I wonder if we actually encounter such dumps in real world examples or if these are just in the tests. If the latter is the case we need some heuristic to be able to detect the language.

I could default to C++ for the time being though.

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The ambiguity of headers is also exposed by this causing TestVarID::varid_header to fail. This relates to the strange logic that was uncovered previously by #4681. So that also needs to be addressed before this can be merged.

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It turns out there is actually a valid state where we have no language - when we process markup files (i.e. .qml).

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Requires #5896 to be merged first.

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I am not too happy about the multiple asserts but it is possible to create a TokenList in various ways. I tried to narrow it with some refactoring but that introduced some bigger problems.

[danmar]

Several of the test Clang AST dumps have no filename specified which causes the language not be be determined.

For your information we have in the Cppcheck Premium backlog a task to look at improving clang AST import.. it's way in the future we will at least not work on this for the next year..

I have the feeling it might be a good idea to fork clang and update the dump output so it's more parser-friendly. I believe we just need to tweak the dumping code which should be relatively limited in scope. I envision it will be a big job to maintain it.. but it would probably be worth it.

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#5961 is another step in improving things.

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And yet another step with #5963.

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With the adjustments the asserts are now limited to TokenList. I put them behind a define so they can be easily disabled came release. I also added some fallbacks so we do not have an undetermined language.

I hope to make further improvements that make the asserts unnecessary.

[danmar]

sorry it's not so nice to have such ifdefs over and over. Is the idea that I will undefine ASSERT_LANG in release builds somehow? How about this code:

#ifdef N_ASSERT_LANG
#define ASSERT_LANG(cond) throw InternalError(nullptr, __FILE__ ": assertion error: " #cond);
#else
#include <cassert>
#define ASSERT_LANG(cond) assert(cond)
#endif

.. and I build with -DN_ASSERT_LANG in release builds?

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This is temporary and the intention is to simply disable the define in source. I can already provide a PR so it will not be missed. In case I am able to make the appropriate improvements the asserts will one by one go away. In case I am not they will not be enabled at all. Not pretty but it quite local and does not spill into other code.

I do not want an I do not want an InternalError for this as this is nothing the user should ever see. We will also not be able to generate the appropriate information the user needs to provide so we can figure out the location in case the source cannot be provided. Also this would require modifications in daca so I get the desired information. That would cause a ripple effect I want to avoid.

[danmar]

at least I'd suggest that we avoid ifdefs over and over.. for instance:

#ifndef N_ASSERT_LANG
#include <cassert>
#define ASSERT_LANG(cond) assert(cond)
#endif

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Will do.

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Done.

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Any more feedback on this? Otherwise I am going to merge this tomorrow so I can hopefully finish up the task during this dev cycle.

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Still needs a bit of work. Files without any extension have no language set. Those need to default to C++ by default as per the existing code.

But we treat headers as C by default - that is inconsistent. That should be aligned to be C by default. Extension-less files are most likely C++ anyways but those should be identified by the Emacs marker (see https://trac.cppcheck.net/ticket/10692). I will address this in a different PR.

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Ugh. Turns out to get this done properly we need to move towards only using FileSettings.

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I addressed this with another fallback for now.

[danmar]

lgtm