sql: better errors for invalid argument number

sql/expression/function/ceil_round_floor.go

@@ -155,7 +155,7 @@ type Round struct {
 func NewRound(args ...sql.Expression) (sql.Expression, error) {
 	argLen := len(args)
 	if argLen == 0 || argLen > 2 {
-		return nil, sql.ErrInvalidArgumentNumber.New("1 or 2", argLen)
+		return nil, sql.ErrInvalidArgumentNumber.New("ROUND", "1 or 2", argLen)
 	}
 
 	var right sql.Expression

sql/expression/function/coalesce.go

@@ -15,7 +15,7 @@ type Coalesce struct {
 // NewCoalesce creates a new Coalesce sql.Expression.
 func NewCoalesce(args ...sql.Expression) (sql.Expression, error) {
 	if len(args) == 0 {
-		return nil, sql.ErrInvalidArgumentNumber.New("1 or more", 0)
+		return nil, sql.ErrInvalidArgumentNumber.New("COALESCE", "1 or more", 0)
 	}
 
 	return &Coalesce{args}, nil

sql/expression/function/concat.go

@@ -20,7 +20,7 @@ var ErrConcatArrayWithOthers = errors.NewKind("can't concat a string array with
 // NewConcat creates a new Concat UDF.
 func NewConcat(args ...sql.Expression) (sql.Expression, error) {
 	if len(args) == 0 {
-		return nil, sql.ErrInvalidArgumentNumber.New("1 or more", 0)
+		return nil, sql.ErrInvalidArgumentNumber.New("CONCAT", "1 or more", 0)
 	}
 
 	for _, arg := range args {

sql/expression/function/concat_ws.go

@@ -18,7 +18,7 @@ type ConcatWithSeparator struct {
 // NewConcatWithSeparator creates a new NewConcatWithSeparator UDF.
 func NewConcatWithSeparator(args ...sql.Expression) (sql.Expression, error) {
 	if len(args) == 0 {
-		return nil, sql.ErrInvalidArgumentNumber.New("1 or more", 0)
+		return nil, sql.ErrInvalidArgumentNumber.New("CONCAT_WS", "1 or more", 0)
 	}
 
 	for _, arg := range args {

sql/expression/function/json_extract.go

@@ -18,7 +18,7 @@ type JSONExtract struct {
 // NewJSONExtract creates a new JSONExtract UDF.
 func NewJSONExtract(args ...sql.Expression) (sql.Expression, error) {
 	if len(args) < 2 {
-		return nil, sql.ErrInvalidArgumentNumber.New(2, len(args))
+		return nil, sql.ErrInvalidArgumentNumber.New("JSON_EXTRACT", 2, len(args))
 	}
 
 	return &JSONExtract{args[0], args[1:]}, nil

sql/expression/function/logarithm.go

@@ -1,13 +1,13 @@
 package function
 
 import (
+	"fmt"
 	"math"
 	"reflect"
-	"fmt"
 
-	"gopkg.in/src-d/go-mysql-server.v0/sql/expression"
-	"gopkg.in/src-d/go-mysql-server.v0/sql"
 	"gopkg.in/src-d/go-errors.v1"
+	"gopkg.in/src-d/go-mysql-server.v0/sql"
+	"gopkg.in/src-d/go-mysql-server.v0/sql/expression"
 )
 
 // ErrInvalidArgumentForLogarithm is returned when an invalid argument value is passed to a
@@ -94,7 +94,7 @@ type Log struct {
 func NewLog(args ...sql.Expression) (sql.Expression, error) {
 	argLen := len(args)
 	if argLen == 0 || argLen > 2 {
-		return nil, sql.ErrInvalidArgumentNumber.New("1 or 2", argLen)
+		return nil, sql.ErrInvalidArgumentNumber.New("LOG", "1 or 2", argLen)
 	}
 
 	if argLen == 1 {

sql/expression/function/rpad_lpad.go

@@ -5,13 +5,14 @@ import (
 	"reflect"
 	"strings"
 
-	"gopkg.in/src-d/go-mysql-server.v0/sql"
 	"gopkg.in/src-d/go-errors.v1"
+	"gopkg.in/src-d/go-mysql-server.v0/sql"
 )
 
 var ErrDivisionByZero = errors.NewKind("division by zero")
 
 type padType rune
+
 const (
 	lPadType padType = 'l'
 	rPadType padType = 'r'
@@ -28,7 +29,7 @@ func NewPadFunc(pType padType) func(e ...sql.Expression) (sql.Expression, error)
 func NewPad(pType padType, args ...sql.Expression) (sql.Expression, error) {
 	argLen := len(args)
 	if argLen != 3 {
-		return nil, sql.ErrInvalidArgumentNumber.New("3", argLen)
+		return nil, sql.ErrInvalidArgumentNumber.New(string(pType)+"pad", "3", argLen)
 	}
 
 	return &Pad{args[0], args[1], args[2], pType}, nil

sql/expression/function/substring.go

@@ -32,7 +32,7 @@ func NewSubstring(args ...sql.Expression) (sql.Expression, error) {
 		start = args[1]
 		ln = args[2]
 	default:
-		return nil, sql.ErrInvalidArgumentNumber.New("2 or 3", len(args))
+		return nil, sql.ErrInvalidArgumentNumber.New("SUBSTRING", "2 or 3", len(args))
 	}
 	return &Substring{str, start, ln}, nil
 }

sql/functionregistry.go

@@ -9,7 +9,7 @@ var ErrFunctionNotFound = errors.NewKind("function not found: %s")
 
 // ErrInvalidArgumentNumber is returned when the number of arguments to call a
 // function is different from the function arity.
-var ErrInvalidArgumentNumber = errors.NewKind("expecting %v arguments for calling this function, %d received")
+var ErrInvalidArgumentNumber = errors.NewKind("%s: expecting %v arguments for calling this function, %d received")
 
 // Function is a function defined by the user that can be applied in a SQL
 // query.