How bad is it to use hyphens in a conan package name?

Question

Suppose I have a librari named foo-bar, and I've written a conanfile.py for it. When running conan create for it, I get the warning:

WARN: Name containing special chars is discouraged 'foo-bar'

right away.

My question: How strongly is this discouraged? How bad is it - if at all - to have a Conan package name with hyphens/minus chars?

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PS - In case it matters, I'm using Conan 2.0.13 and am hoping to get my package onto the Conan Center.

Answer 1

TL;DR: There's a risk of conflicts when exporting packages whose names only vary in the special characters +/-/_. For example foo+bar, foo-bar, and foo_bar.

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Looking at the source where that warning is emitted, there's a comment that provides a bit of context:

# Warn if they use .+- in the name/user/channel, as it can be problematic for generators
pattern = re.compile(r'[.+-]')
if pattern.search(self.name):
    ConanOutput().warning(f"Name containing special chars is discouraged '{self.name}'")

This check was added in PR #12053 (issue #11857), which was a response to PR #11826 (issue #11822). The root issue was that +s and -s in package names would both become normalized to _ in some contexts, which could create ambiguity if two package names differed only in their use of +/-/_.

How bad using a - is depends on whether you think there's a risk of conflicts from exporting two packages that vary only in +/-/_.

I do not see any references about using -s being officially deprecated. The tutorial in the docs still states that -s are valid in package names:

name: a string, with a minimum of 2 and a maximum of 100 lowercase characters that defines the package name. It should start with alphanumeric or underscore and can contain alphanumeric, underscore, +, ., - characters.