fix naïve replacement for stmt args (#30)

Author: intamyuto

statement.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql/driver"
 	"fmt"
+	"regexp"
 	"strings"
 	"time"
 
@@ -92,19 +93,17 @@ func template(query string) string {
 }
 
 func statement(tmpl string, args []driver.NamedValue) string {
-	var replacements []string
+	stmt := tmpl
 	for _, arg := range args {
-		var placeholder string
+		var re *regexp.Regexp
 		if arg.Name != "" {
-			placeholder = fmt.Sprintf("@%s", arg.Name)
+			re = regexp.MustCompile(fmt.Sprintf("@%s%s", arg.Name, `\b`))
 		} else {
-			placeholder = fmt.Sprintf("@p%d", arg.Ordinal)
+			re = regexp.MustCompile(fmt.Sprintf("@p%d%s", arg.Ordinal, `\b`))
 		}
 		val := fmt.Sprintf("%v", arg.Value)
-		replacements = append(replacements, placeholder, val)
+		stmt = re.ReplaceAllString(stmt, val)
 	}
-	r := strings.NewReplacer(replacements...)
-	stmt := r.Replace(tmpl)
 	return stmt
 }
 

statement_test.go

@@ -0,0 +1,39 @@
+package impala
+
+import (
+	"database/sql/driver"
+	"testing"
+)
+
+func TestStatement(t *testing.T) {
+	tests := []struct {
+		stmt string
+		args []driver.NamedValue
+		target  string
+	}{
+		{
+			stmt: "@p1 p1",
+			args: []driver.NamedValue{
+				driver.NamedValue{Ordinal: 1, Value: "val_1"},
+			},
+			target: "val_1 p1",
+		},
+		{
+			stmt: "@p1 @p10 @p11 @named @named1 @p1",
+			args: []driver.NamedValue{
+				driver.NamedValue{Ordinal: 1, Value: "val_1"},
+				driver.NamedValue{Ordinal: 10, Name: "named", Value: "val_named"},
+				driver.NamedValue{Ordinal: 11, Value: "val_11"},
+			},
+			target: "val_1 @p10 val_11 val_named @named1 val_1",
+		},
+	}
+
+	for _, tt := range tests {
+		result := statement(tt.stmt, tt.args)
+
+		if result != tt.target {
+			t.Fatalf("mismatch for statement: %q\n\ttarget: %q\n\tresult: %q", tt.stmt, tt.target, result)
+		}
+	}
+}