Difference between '#' and ';' characters in platformio.ini file comments

jking · May 21, 2024, 10:17pm

I was wondering what was the difference between these characters when doing comments, because both are ignored when building a project, right?

sivar2311 · May 22, 2024, 3:15am

As per documentation "; " should be used for comments.

It seems that “#” is also accepted.
To be on the safe side, follow the specification provided in the documentation.

maxgerhardt · May 22, 2024, 3:21am

Technically there’s a slight difference:

github.com

platformio/platformio-core/blob/4075789a32ff09dd2a1615b986504d40e80e5f84/platformio/project/config.py#L75-L79


      
          # comment
          if not item or item.startswith((";", "#")):
              continue
          if ";" in item:
              item = ProjectConfigBase.INLINE_COMMENT_RE.sub("", item).strip()

github.com

platformio/platformio-core/blob/4075789a32ff09dd2a1615b986504d40e80e5f84/platformio/project/config.py#L91-L99


      
          def __init__(self, path=None, parse_extra=True, expand_interpolations=True):
              path = self.get_default_path() if path is None else path
              self.path = path
              self.expand_interpolations = expand_interpolations
              self.warnings = []
              self._parsed = []
              self._parser = configparser.ConfigParser(inline_comment_prefixes=("#", ";"))
              if path and os.path.isfile(path):
                  self.read(path, parse_extra)

So while both ; and # are comments, inside a single item, only the ; functions always as a comment.

Say e.g. you want to reference a certain branch of a github repo with

lib_deps =
   https://github.com/myuser/myrepo.git#specific_branch

Then the # is not interpreted as a comment start but rather the branch name. If it were a ;, it would just reference https://github.com/myuser/myrepo.git. So, by using only ; as the comment character, you’re on the safe side.

jking · May 22, 2024, 3:51am

Nice. I read before in documentation that " ; " is used for comments, I was just wondering why not " # " too