Allow version to be set manually

[assistcontrol]

When Caddy is built from a release tarball (as downloaded from GitHub), caddy version returns an empty string. This causes confusion for downstream packagers.

With this commit, VersionString can be set with eg.
go build (...) -ldflags '-X (...).VersionString=v1.2.3'
Then the short form version will be "v1.2.3", and the full version string will begin with "v1.2.3 ".

[assistcontrol]

See #5065 for some discussion on this.

[mholt]

Thanks! I just pushed some revisions that prefer the embedded version if available, but still prepends the CustomVersion (renamed from VersionString) if set.

Let me know if that's OK with you, and if so I'll merge this and maybe release 2.6.2 here pretty soon.

[assistcontrol]

If I'm reading it correctly, CustomVersion is no longer prepended to full if full is non-empty.

It looks like it is still possible for full to wind up being empty.

if full == "" {
	full = CustomVersion
} else if CustomVersion != "" {
	full = CustomVersion + " " + full
}

If full = "" and CustomVersion = "", then full will be empty. Similarly, if full = "" and CustomVersion="foo", then full = "foo " (with a trailing space).

Perhaps instead, default an empty full to simple, and prepend CustomVersion:

	if simple == "" || simple == "(devel)" {
		simple = "unknown"
		if CustomVersion != "" {
			simple = CustomVersion
		} else {
			simple = "unknown"
		}
	}

	if full == "" {
		if CustomVersion == "" {
			full = simple
		} else {
			full = CustomVersion
		}
	} else {
		full = CustomVersion + " " + full
	}

[assistcontrol]

The first simple = "unknown" is probably superfluous.

It may also be safe to assume that an empty full should just be simple which will be CustomVersion, because an empty full means an empty simple:

	if simple == "" || simple == "(devel)" {
		if CustomVersion != "" {
			simple = CustomVersion
		} else {
			simple = "unknown"
		}
	}

	if full == "" {
		full = simple
	} else {
		full = CustomVersion + " " + full
	}

[mholt]

(Can you do inline comments next time? That'll make code review easier.)

If I'm reading it correctly, CustomVersion is no longer prepended to full if full is non-empty.

It is still prepended: https://github.com/caddyserver/caddy/pull/5072/files#diff-57caf2be698e920a2599b611efd1b33dea35fd79976cacdf3354ab3f55706515R932

It looks like it is still possible for full to wind up being empty.

Yes, but only if there is absolutely no version information embedded and CustomVersion is empty, then full will be empty. This is probably OK, rather than covering up the fact with a non-empty value? I dunno.

Similarly, if full = "" and CustomVersion="foo", then full = "foo " (with a trailing space).

Are you sure that's true? Not in my testing.

Let's sort out those understandings and then we can make more tweaks if needed.

[mholt]

@assistcontrol Is there anything else before I go ahead and merge this in? Will probably do so in a day or two otherwise.

[assistcontrol]

Sorry, IRL has been busy.

It looks like it is still possible for full to wind up being empty.

Yes, but only if there is absolutely no version information embedded and CustomVersion is empty, then full will be empty. This is probably OK, rather than covering up the fact with a non-empty value? I dunno.

All it takes for there to be absolutely no version information embedded is to download any of the tarballs on the GH releases page.

I guess the question is, when someone downloads a tarball from the GH release page and doesn't know to set CustomVersion, would you prefer that caddy version print nothing, or unknown? I have my preference ("unknown" is better than wondering whether the caddy version command itself is broken) but I'm behind you and pleased with your edits no matter which path you prefer here.

[mholt]

I guess we could print "unknown" for the full version too.

[mholt]

CI is stuck, so going ahead and merging. Thanks for your contribution @assistcontrol !

GitHub incident: https://www.githubstatus.com/incidents/smn1qtqvbsb6