From 23b9df06944881cf9442a1c52208a3760e623e6f Mon Sep 17 00:00:00 2001
From: Yao Zongyou <yaozongyou@vip.qq.com>
Date: Tue, 25 Jun 2019 07:59:33 +0800
Subject: [PATCH] Fix s3select TRIM function's nil pointer dereference bug
 (#7817)

---
 pkg/s3select/sql/analysis.go |  9 +++++++++
 pkg/s3select/sql/funceval.go | 21 +++++++++++++--------
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/pkg/s3select/sql/analysis.go b/pkg/s3select/sql/analysis.go
index b246be4c1..e0a5e8eba 100644
--- a/pkg/s3select/sql/analysis.go
+++ b/pkg/s3select/sql/analysis.go
@@ -274,6 +274,15 @@ func (e *FuncExpr) analyze(s *Select) (result qProp) {
 		}
 		return result
 
+	case sqlFnTrim:
+		if e.Trim.TrimChars != nil {
+			result.combine(e.Trim.TrimChars.analyze(s))
+		}
+		if e.Trim.TrimFrom != nil {
+			result.combine(e.Trim.TrimFrom.analyze(s))
+		}
+		return result
+
 	case sqlFnSubstring:
 		errVal := fmt.Errorf("Invalid argument(s) to %s", string(funcName))
 		result.combine(e.Substring.Expr.analyze(s))
diff --git a/pkg/s3select/sql/funceval.go b/pkg/s3select/sql/funceval.go
index 8b968e6bd..51dcbdbd9 100644
--- a/pkg/s3select/sql/funceval.go
+++ b/pkg/s3select/sql/funceval.go
@@ -337,20 +337,25 @@ func handleSQLSubstring(r Record, e *SubstringFunc) (val *Value, err error) {
 }
 
 func handleSQLTrim(r Record, e *TrimFunc) (res *Value, err error) {
-	charsV, cerr := e.TrimChars.evalNode(r)
-	if cerr != nil {
-		return nil, cerr
-	}
-	inferTypeAsString(charsV)
-	chars, ok := charsV.ToString()
-	if !ok {
-		return nil, errNonStringTrimArg
+	chars := ""
+	ok := false
+	if e.TrimChars != nil {
+		charsV, cerr := e.TrimChars.evalNode(r)
+		if cerr != nil {
+			return nil, cerr
+		}
+		inferTypeAsString(charsV)
+		chars, ok = charsV.ToString()
+		if !ok {
+			return nil, errNonStringTrimArg
+		}
 	}
 
 	fromV, ferr := e.TrimFrom.evalNode(r)
 	if ferr != nil {
 		return nil, ferr
 	}
+	inferTypeAsString(fromV)
 	from, ok := fromV.ToString()
 	if !ok {
 		return nil, errNonStringTrimArg