ContainerRegistry: Reject other invalid characters in repository names

Author: euanh

Sources/ContainerRegistry/ImageReference.swift

@@ -124,6 +124,12 @@ extension ImageReference {
                 throw RepositoryParseError.containsUppercaseLetters(rawValue)
             }
 
+            // https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pulling-manifests
+            let regex = /[a-z0-9]+((\.|_|__|-+)[a-z0-9]+)*(\/[a-z0-9]+((\.|_|__|-+)[a-z0-9]+)*)*/
+            if try regex.wholeMatch(in: rawValue) == nil {
+                throw RepositoryParseError.invalidReferenceFormat(rawValue)
+            }
+
             value = rawValue
         }
 
@@ -140,5 +146,6 @@ extension ImageReference {
     public enum RepositoryParseError: Error, Equatable {
         case emptyString
         case containsUppercaseLetters(String)
+        case invalidReferenceFormat(String)
     }
 }

Tests/ContainerRegistryTests/ImageReferenceTests.swift

@@ -146,6 +146,10 @@ struct ReferenceTests {
         #expect(throws: ImageReference.RepositoryParseError.containsUppercaseLetters("helloWorld")) {
             try ImageReference(fromString: "localhost:5555/helloWorld")
         }
+
+        #expect(throws: ImageReference.RepositoryParseError.invalidReferenceFormat("hello^world")) {
+            try ImageReference(fromString: "localhost:5555/hello^world")
+        }
     }
 
     @Test