Implement LPOS: validate arguments outside transaction

cmd_list.go

@@ -168,16 +168,71 @@ func (m *Miniredis) cmdLindex(c *server.Peer, cmd string, args []string) {
 
 // LPOS key element [RANK rank] [COUNT num-matches] [MAXLEN len]
 func (m *Miniredis) cmdLpos(c *server.Peer, cmd string, args []string) {
+	if !m.handleAuth(c) {
+		return
+	}
+	if m.checkPubsub(c, cmd) {
+		return
+	}
+
 	if len(args) == 1 {
 		setDirty(c)
 		c.WriteError(errWrongNumber(cmd))
 		return
 	}
-	if !m.handleAuth(c) {
+
+	// Extract options from arguments if present.
+	//
+	// Redis allows duplicate options and uses the last specified.
+	// `LPOS key term RANK 1 RANK 2` is effectively the same as
+	// `LPOS key term RANK 2`
+	// Default options.
+	if len(args)%2 == 1 {
+		setDirty(c)
+		c.WriteError(msgSyntaxError)
 		return
 	}
-	if m.checkPubsub(c, cmd) {
-		return
+	rank, count := 1, 1 // Default values
+	var maxlen int      // Default value is the list length (see below)
+	var countSpecified, maxlenSpecified bool
+	if len(args) > 2 {
+		for i := 2; i < len(args); i++ {
+			if i%2 == 0 {
+				val := args[i+1]
+				var err error
+				switch strings.ToLower(args[i]) {
+				case "rank":
+					if rank, err = strconv.Atoi(val); err != nil {
+						setDirty(c)
+						c.WriteError(msgInvalidInt)
+						return
+					}
+					if rank == 0 {
+						setDirty(c)
+						c.WriteError(msgRankIsZero)
+						return
+					}
+				case "count":
+					countSpecified = true
+					if count, err = strconv.Atoi(val); err != nil || count < 0 {
+						setDirty(c)
+						c.WriteError(msgCountIsNegative)
+						return
+					}
+				case "maxlen":
+					maxlenSpecified = true
+					if maxlen, err = strconv.Atoi(val); err != nil || maxlen < 0 {
+						setDirty(c)
+						c.WriteError(msgMaxLengthIsNegative)
+						return
+					}
+				default:
+					setDirty(c)
+					c.WriteError(msgSyntaxError)
+					return
+				}
+			}
+		}
 	}
 
 	withTx(m, c, func(c *server.Peer, ctx *connCtx) {
@@ -195,55 +250,6 @@ func (m *Miniredis) cmdLpos(c *server.Peer, cmd string, args []string) {
 		}
 		l := db.listKeys[key]
 
-		// Default options.
-		rank := 1
-		count := 1
-		maxlen := len(l)
-
-		// Extract options from arguments if present.
-		//
-		// Redis allows duplicate options and uses the last specified.
-		// `LPOS key term RANK 1 RANK 2` is effectively the same as
-		// `LPOS key term RANK 2`
-		if len(args)%2 == 1 {
-			c.WriteError(msgSyntaxError)
-			return
-		}
-		var countSpecified bool
-		if len(args) > 2 {
-			for i := 2; i < len(args); i++ {
-				if i%2 == 0 {
-					val := args[i+1]
-					var err error
-					switch strings.ToLower(args[i]) {
-					case "rank":
-						if rank, err = strconv.Atoi(val); err != nil {
-							c.WriteError(msgInvalidInt)
-							return
-						}
-						if rank == 0 {
-							c.WriteError(msgRankIsZero)
-							return
-						}
-					case "count":
-						countSpecified = true
-						if count, err = strconv.Atoi(val); err != nil || count < 0 {
-							c.WriteError(msgCountIsNegative)
-							return
-						}
-					case "maxlen":
-						if maxlen, err = strconv.Atoi(val); err != nil || maxlen < 0 {
-							c.WriteError(msgMaxLengthIsNegative)
-							return
-						}
-					default:
-						c.WriteError(msgSyntaxError)
-						return
-					}
-				}
-			}
-		}
-
 		// RANK cannot be zero (see above).
 		// If RANK is positive search forward (left to right).
 		// If RANK is negative search backward (right to left).
@@ -252,7 +258,7 @@ func (m *Miniredis) cmdLpos(c *server.Peer, cmd string, args []string) {
 			comparisons := len(l)
 			// Only use max length if specified, not zero, and less than total length.
 			// When max length is specified, but is zero, this means "unlimited".
-			if maxlen != 0 && maxlen < len(l) {
+			if maxlenSpecified && maxlen != 0 && maxlen < len(l) {
 				comparisons = maxlen
 			}
 			if rank > 0 {