Protect canonical operand prefixes from aliases

registry.go

@@ -326,7 +326,7 @@ func traceCanonicalPath(roots map[string]*canonicalNode, path commandpath.Path)
 			continue
 		}
 		operandCount := len(path) - index
-		if current != nil && acceptsOperandCount(current.command, operandCount) {
+		if current != nil && acceptsOperandPrefix(current.command, operandCount) {
 			return commandAliasTrace{operandOwner: current}
 		}
 		return commandAliasTrace{}
@@ -334,14 +334,15 @@ func traceCanonicalPath(roots map[string]*canonicalNode, path commandpath.Path)
 	return commandAliasTrace{exact: current}
 }
 
-func acceptsOperandCount(command Command, count int) bool {
+// acceptsOperandPrefix reports whether more operands could complete this prefix.
+// A source need not already satisfy the command's minimum to intercept it.
+func acceptsOperandPrefix(command Command, count int) bool {
 	if command.record == nil || command.record.payload == nil || !command.record.payload.hasRun() {
 		return false
 	}
 	arguments := command.record.payload.bridgeArguments()
-	minimum, maximum := 0, 0
+	maximum := 0
 	for _, argument := range arguments {
-		minimum += argument.Min
 		if maximum >= 0 {
 			if argument.Max < 0 {
 				maximum = -1
@@ -350,5 +351,5 @@ func acceptsOperandCount(command Command, count int) bool {
 			}
 		}
 	}
-	return count >= minimum && (maximum < 0 || count <= maximum)
+	return maximum < 0 || count <= maximum
 }