Constraint for exact version match

[vladykin]

semver.NewConstraint seems to always do fuzzy matching, even when no relational operators are specified, and even if '=' operator is used.

Example:

func main() {
	tests := [...][2]string{
		{"1.0-af839ds6", "1.0-ff164935"},
		{"=1.0-af839ds6", "1.0-ff164935"},
		{"1.0+af839ds6", "1.0+ff164935"},
		{"=1.0+af839ds6", "1.0+ff164935"},
	}

	for i := 0; i < len(tests); i++ {
		c, err := semver.NewConstraint(tests[i][0])
		if err != nil {
			return
		}

		v, err := semver.NewVersion(tests[i][1])
		if err != nil {
			return
		}

		log.Printf("%s check %s  => %t", c, v, c.Check(v))
	}
}

All these checks produce true.

Is there a way to specify a constraint that would require exact match of all components, including preprelease and build metadata components of the version? I would expect it to happen with '=' operator, but currently the matching is still fuzzy.

This is somewhat similar to #164, except that I don't need any pattern at all, just plain exact match.

My use case also involves helm. I want to tell it to use exact build of the helm chart, and make it fail if it does not find exact match. Currently, if helm does not find exact match, it uses semver.NewConstraint and looks for a version that matches the constraint. And the constraint gives such unexpected matches, as in the example above.

[mattfarina]

@vladykin This isn't an exact version match situation. No patch version is ever specified and it's required.

Take the first example of {"1.0-af839ds6", "1.0-ff164935"},.

This is saying that for 1.0.X-af839ds6 (where X is a wildcard) find a match. When you leave out a major.minor.patch section it's assumed to be a wildcard. This is what libraries like this generally tend to do and is patterned off what libraries in other languages have long done.

1.0-ff164935 as a value expands to 1.0.0-ff164935. This fits within the pattern above due to the X wildcard.

if you want to deal with exact matches you need to include all 3 required parts of a semantic version.

[vladykin]

Thanks, thank helps!

I confirm that specifying the constraint with all 3 components major.minor.patch makes the matching respect the prerelease, i.e.

• constraint 1.0.0-ff164935 or =1.0.0-ff164935 matches version 1.0.0-ff164935
• constraint 1.0.0-af839ds6 or =1.0.0-af839ds6 does not match version 1.0.0-ff164935

Is there a similar trick to respect metadata during matching?
I still see that constraint =1.0.0+af839ds6 matches version 1.0.0+ff164935

[mattfarina]

Is there a similar trick to respect metadata during matching?

Per the spec... "Build metadata MUST be ignored when determining version precedence." So, there is no way to match on metadata as it is supposed to be ignored.

[vladykin]

Understood, thanks!