Checking 4 spaces indent in C files in CI

[junaruga]

Seeing the PR #973 (thanks for the PR!), I am considering if we can check if the indent is 4 spaces without tabs in CI. Right now I am seeing the following tools.

• clang-format: https://clang.llvm.org/docs/ClangFormat.html
• GNU indent: https://www.gnu.org/software/indent/

If we only check if C files don't include tabs. We may just apply the following kind of script.

$ cat check_no_tab.sh
#!/bin/bash

set -eu

if grep -rPn '\t' ext/openssl/; then
    echo "FAIL"
    exit 1
fi

echo "OK"
exit 0

OK case:

$ ./check_no_tab.sh
OK

Error case:

$ ./check_no_tab.sh
ext/openssl/ossl_ssl.c:3302:	DefIVarID(hostname);
FAIL

What do you think?

[junaruga]

I see the clang-format and GNU indent (indent) check not only indent but also other things. That doesn't fit our case. Perhaps, just creating a Ruby script to check the indents may be good.

[rhenium]

IIRC the issue with clang-format and indent is that they don't fully support Ruby's style, particularly labels:

void
func(void)
{
    switch (a) {
      case b:
        puts("b");
    }
  err:
    puts("x");
}

Perhaps we may want to adopt tool/auto-style.rb from ruby core?

https://github.com/ruby/ruby/blob/d3a9a17b6f908a64d8cf7b35c5e7337be3fc7cc5/tool/auto-style.rb#L189-L232

[junaruga]

Perhaps we may want to adopt tool/auto-style.rb from ruby core?

This sounds good idea!