check_names misses typo in PSA macro name

[gilles-peskine-arm]

Add the following code to include/mbedtls/check_config.h:

#if defined(MBEDTLS_LMS_C) && !defined(PSA_WANT_ALG_SHA256)
//#error "MBEDTLS_LMS_C defined, but not misspelled prerequisite"
#endif

(you can't have the actual #error because that causes a build failure)

Expectation: tests/scripts/check_names.py complains that PSA_WANT_ALG_SHA256 is a likely typo (the correct spelling is PSA_WANT_ALG_SHA_256). It would do so if the dependency was on MBEDTLS_SHA_256_C (misspelled for MBEDTLS_SHA256_C).

Actual behavior as of 0fe6631: tests/scripts/check_names.py is happy (as long as make lib works in the full config).

[lpy4105]

I'm going to work on this enhancement. I added some experimental code in check_names.py to check the PSA words the same way as the MBED words. I found that unlike MBED words, not all of the PSA_XXX symbols (macros and enumeration) are defined in the headers so there would be false negative errors of 'likely typo' for these references(e.g. PSA_PAKE_SEQ_INVALID). Any suggestions for these symbols?

[gilles-peskine-arm]

Possible solution: make check_names.py also look in .c files for definitions of macro/enum names.

Another possible solution, perhaps: does clang-tidy have an applicable check? It can enforce that defined identifiers have a certain prefix, but I haven't found a check that's similar to the typo part of check_names. So maybe in the medium term check_names.py could be simplified to only do the typo check, and the part about enforcing the namespace could be removed.