cli: pick next -seq version by numeric max, not lexical last

internal/cli/commands.go

@@ -27,24 +27,27 @@ func nextSeqVersion(matches []string, seqDigits int) (string, error) {
 
 	nextSeq := uint64(1)
 
-	if len(matches) > 0 {
-		filename := matches[len(matches)-1]
+	// filepath.Glob returns matches in lexical order, so the highest sequence
+	// number is not necessarily last (e.g. "9_" sorts after "10_"). Scan every
+	// match and use the numeric maximum.
+	for _, filename := range matches {
 		matchSeqStr := filepath.Base(filename)
 		idx := strings.Index(matchSeqStr, "_")
 
 		if idx < 1 { // Using 1 instead of 0 since there should be at least 1 digit
 			return "", fmt.Errorf("malformed migration filename: %s", filename)
 		}
 
-		var err error
 		matchSeqStr = matchSeqStr[0:idx]
-		nextSeq, err = strconv.ParseUint(matchSeqStr, 10, 64)
+		matchSeq, err := strconv.ParseUint(matchSeqStr, 10, 64)
 
 		if err != nil {
 			return "", err
 		}
 
-		nextSeq++
+		if matchSeq >= nextSeq {
+			nextSeq = matchSeq + 1
+		}
 	}
 
 	version := fmt.Sprintf("%0[2]*[1]d", nextSeq, seqDigits)

internal/cli/commands_test.go

@@ -88,6 +88,7 @@ func (s *CreateCmdSuite) TestNextSeqVersion() {
 		{"Single digit no int", []string{"bad_bad"}, 1, "", errors.New(`strconv.ParseUint: parsing "bad": invalid syntax`)},
 		{"Single digit negative seq", []string{"-5_test"}, 1, "", errors.New(`strconv.ParseUint: parsing "-5": invalid syntax`)},
 		{"Single digit increment", []string{"3_test", "4_test"}, 1, "5", nil},
+		{"Multi digit lexical order", []string{"0_x", "10_x", "11_x", "1_x", "2_x", "9_x"}, 6, "000012", nil},
 		{"Single digit overflow", []string{"9_test"}, 1, "", errors.New("next sequence number 10 too large, at most 1 digits are allowed")},
 		{"Zero-pad initialize", []string{}, 6, "000001", nil},
 		{"Zero-pad malformed", []string{"bad"}, 6, "", errors.New("malformed migration filename: bad")},