fix(semantic): parse Alpine versions with dots that are not followed by a digit

Author: G-Rath

semantic/testdata/alpine-versions.txt

@@ -12,6 +12,17 @@
 
 1.2.3b > 1.2.0d
 
+0.r1 < 0r2
+0..1..0 < 0..1..1
+0...1...0 < 0...1...1
+0...1...0.r1 < 0...1...0.r2
+0...1...0r1 < 0...1...0r2
+0..8 = 0..8
+0..8 > 0...8
+0.8.21.r2 > 0.8.21.r1
+10.2.24.r0 > 10.2.22.r0
+0.8.21.r2 < 0.8.21r2
+
 # letters (invalid) - note on latest apk these are "<" but on 3.x line they're ">"
 1.2.0A < 1.2.0d
 1.2.0D < 1.2.0d

semantic/version-alpine.go

@@ -255,6 +255,12 @@ func parseAlpineNumberComponents(v *alpineVersion, str string) (string, error) {
 	}
 
 	for i, d := range strings.Split(sub, ".") {
+		// while technically not allowed by the spec, currently apk does not
+		// consider it invalid to have a dot that isn't followed by a digit
+		if d == "" {
+			break
+		}
+
 		value, err := convertToBigInt(d)
 
 		if err != nil {