[Refactor] refactor lambda error msg (#17414)

StarRocks · Feb 10, 2023 · 832ffb5 · 832ffb5
1 parent cc3200c
commit 832ffb5
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Showing 2 changed files with 16 additions and 7 deletions.
diff --git a/fe/fe-core/src/main/java/com/starrocks/analysis/Expr.java b/fe/fe-core/src/main/java/com/starrocks/analysis/Expr.java
@@ -1335,20 +1335,22 @@ public boolean hasLambdaFunction(Expr expression) {
         }
         if (num == 1 && (pos == 0 || pos == children.size() - 1)) {
             if (children.size() <= 1) {
-                throw new SemanticException("Lambda functions should work with inputs in high-order functions.");
+                throw new SemanticException("Lambda functions need array inputs in high-order functions.");
             }
             return true;
         } else if (num > 1) {
-            throw new SemanticException("A high-order function can have one lambda function.");
+            throw new SemanticException("A high-order function should have only 1 lambda function, " +
+                    "but there are " + num + " lambda functions.");
         } else if (pos > 0 && pos < children.size() - 1) {
             throw new SemanticException(
-                    "Lambda functions can only be the first or last argument of any high-order function, " +
-                            "or lambda arguments should be in ().");
+                    "Lambda functions should only be the first or last argument of any high-order function, " +
+                            "or lambda arguments should be in () if there are more than one lambda arguments, " +
+                            "like (x,y)->x+y.");
         } else if (num == 0) {
             if (expression instanceof FunctionCallExpr) {
                 String funcName = ((FunctionCallExpr) expression).getFnName().getFunction();
                 if (funcName.equals(FunctionSet.ARRAY_MAP) || funcName.equals(FunctionSet.TRANSFORM)) {
-                    throw new SemanticException(funcName + " should not without lambda function input.");
+                    throw new SemanticException("There are no lambda functions in high-order function " + funcName);
                 }
             }
         }

diff --git a/fe/fe-core/src/main/java/com/starrocks/sql/analyzer/ExpressionAnalyzer.java b/fe/fe-core/src/main/java/com/starrocks/sql/analyzer/ExpressionAnalyzer.java
@@ -168,7 +168,14 @@ private Expr rewriteHighOrderFunction(Expr expr) {
     // only high-order functions can use lambda functions.
     void analyzeHighOrderFunction(Visitor visitor, Expr expression, Scope scope) {
         if (!isHighOrderFunction(expression)) {
-            throw new SemanticException("Lambda Functions can only be used in supported high-order functions.");
+            String funcName = "";
+            if (expression instanceof FunctionCallExpr) {
+                funcName = ((FunctionCallExpr) expression).getFnName().getFunction();
+            } else {
+                funcName = expression.toString();
+            }
+            throw new SemanticException(funcName + " can't use lambda functions, " +
+                    "as it is not a supported high-order function.");
         }
         int childSize = expression.getChildren().size();
         // move the lambda function to the first if it is at the last.
@@ -187,7 +194,7 @@ void analyzeHighOrderFunction(Visitor visitor, Expr expression, Scope scope) {
                 expr.setType(Type.ARRAY_INT); // Let it have item type.
             }
             if (!expr.getType().isArrayType()) {
-                throw new SemanticException("Lambda inputs should be arrays.");
+                throw new SemanticException(i + "th lambda input should be arrays.");
             }
             Type itemType = ((ArrayType) expr.getType()).getItemType();
             if (itemType == Type.NULL) { // Since slot_ref with Type.NULL is rewritten to Literal in toThrift(),