branch-4.1: [fix](user_var)fix integer typing and prefer Variable.realExpression for argument/type resolution#62524

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/AGENTS.md

@@ -0,0 +1,5 @@
+# Nereids expressions — Review Guide
+
+## checkLegalityBeforeTypeCoercion
+
+- [ ] For all overloaded checkLegalityBeforeTypeCoercion methods, ensure child nodes are obtained via getArguments() or getArgument() instead of children() or child().

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/InPredicate.java

@@ -135,29 +135,30 @@ public boolean nullable() throws UnboundException {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (children().get(0).getDataType().isStructType()) {
+        List<Expression> arguments = getArguments();
+        if (arguments.get(0).getDataType().isStructType()) {
             // we should check in value list is all struct type
-            for (int i = 1; i < children().size(); i++) {
-                if (!children().get(i).getDataType().isStructType() && !children().get(i).getDataType().isNullType()) {
+            for (int i = 1; i < arguments.size(); i++) {
+                if (!arguments.get(i).getDataType().isStructType() && !arguments.get(i).getDataType().isNullType()) {
                     throw new AnalysisException("in predicate struct should compare with struct type list, but got : "
-                            + children().get(i).getDataType().toSql());
+                            + arguments.get(i).getDataType().toSql());
                 }
             }
             return;
         }
 
-        if (children().get(0).getDataType().isArrayType()) {
+        if (arguments.get(0).getDataType().isArrayType()) {
             // we should check in value list is all list type
-            for (int i = 1; i < children().size(); i++) {
-                if (!children().get(i).getDataType().isArrayType() && !children().get(i).getDataType().isNullType()) {
+            for (int i = 1; i < arguments.size(); i++) {
+                if (!arguments.get(i).getDataType().isArrayType() && !arguments.get(i).getDataType().isNullType()) {
                     throw new AnalysisException("in predicate list should compare with struct type list, but got : "
-                            + children().get(i).getDataType().toSql());
+                            + arguments.get(i).getDataType().toSql());
                 }
             }
             return;
         }
 
-        children().forEach(c -> {
+        arguments.forEach(c -> {
             if (c.getDataType().isObjectType()) {
                 throw new AnalysisException("in predicate could not contains object type: " + this.toSql());
             }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Like.java

@@ -96,8 +96,9 @@ public Expression withInferred(boolean inferred) {
     @Override
     public void checkLegalityBeforeTypeCoercion() {
         if (arity() == 3) {
-            if (child(2) instanceof StringLikeLiteral) {
-                String escapeChar = ((StringLikeLiteral) child(2)).getStringValue();
+            Expression escapeArgument = getArgument(2);
+            if (escapeArgument instanceof StringLikeLiteral) {
+                String escapeChar = ((StringLikeLiteral) escapeArgument).getStringValue();
                 if (escapeChar.getBytes().length != 1) {
                     throw new AnalysisException(
                             "like escape character must be a single ascii character: " + escapeChar);

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/ExpressionTrait.java

@@ -21,6 +21,7 @@
 import org.apache.doris.nereids.exceptions.UnboundException;
 import org.apache.doris.nereids.trees.TreeNode;
 import org.apache.doris.nereids.trees.expressions.Expression;
+import org.apache.doris.nereids.trees.expressions.Variable;
 import org.apache.doris.nereids.types.DataType;
 
 import com.google.common.collect.ImmutableList;
@@ -46,12 +47,42 @@ default void checkLegalityBeforeTypeCoercion() {}
     @Developing
     default void checkLegalityAfterRewrite() {}
 
+    /**
+     * getArguments.
+     */
     default List<Expression> getArguments() {
-        return children();
+        boolean hasVariableArg = false;
+        for (Expression arg : children()) {
+            if (arg instanceof Variable) {
+                hasVariableArg = true;
+                break;
+            }
+        }
+        if (hasVariableArg) {
+            ImmutableList.Builder<Expression> arguments = ImmutableList.builder();
+            for (Expression arg : children()) {
+                if (arg instanceof Variable) {
+                    arguments.add(((Variable) arg).getRealExpression());
+                } else {
+                    arguments.add(arg);
+                }
+            }
+            return arguments.build();
+        } else {
+            return children();
+        }
     }
 
+    /**
+     * getArgument.
+     */
     default Expression getArgument(int index) {
-        return child(index);
+        Expression arg = child(index);
+        if (arg instanceof Variable) {
+            return ((Variable) arg).getRealExpression();
+        } else {
+            return arg;
+        }
     }
 
     default List<DataType> getArgumentsTypes() {

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/BoolAnd.java

@@ -67,7 +67,7 @@ public BoolAnd withDistinctAndChildren(boolean distinct, List<Expression> childr
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (!(argType.isBooleanType() || argType.isNumericType())) {
             throw new AnalysisException("bool_and requires a boolean or numeric argument");
         }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/BoolOr.java

@@ -63,7 +63,7 @@ public BoolOr withDistinctAndChildren(boolean distinct, List<Expression> childre
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (!(argType.isBooleanType() || argType.isNumericType())) {
             throw new AnalysisException("bool_or requires a boolean or numeric argument");
         }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/BoolXor.java

@@ -63,7 +63,7 @@ public BoolXor withDistinctAndChildren(boolean distinct, List<Expression> childr
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (!(argType.isBooleanType() || argType.isNumericType())) {
             throw new AnalysisException("bool_xor requires a boolean or numeric argument");
         }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/Histogram.java

@@ -82,7 +82,7 @@ private Histogram(AggregateFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (!(child(0).getDataType() instanceof PrimitiveType)) {
+        if (!(getArgument(0).getDataType() instanceof PrimitiveType)) {
             SearchSignature.throwCanNotFoundFunctionException(this.getName(), getArguments());
         }
         if (arity() == 2 && !getArgument(1).isConstant()) {

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/LinearHistogram.java

@@ -72,7 +72,7 @@ private LinearHistogram(AggregateFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (!(child(0).getDataType() instanceof PrimitiveType)) {
+        if (!(getArgument(0).getDataType() instanceof PrimitiveType)) {
             SearchSignature.throwCanNotFoundFunctionException(this.getName(), getArguments());
         }
     }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/Median.java

@@ -79,7 +79,7 @@ private Median(NullableAggregateFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (((!argType.isNumericType() && !argType.isNullType()) || argType.isOnlyMetricType())) {
             throw new AnalysisException("median requires a numeric parameter: " + toSql());
         }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/MultiDistinctSum.java

@@ -53,7 +53,7 @@ private MultiDistinctSum(NullableAggregateFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if ((!argType.isNumericType() && !argType.isBooleanType() && !argType.isNullType())
                 || argType.isOnlyMetricType()) {
             throw new AnalysisException("sum requires a numeric or boolean parameter: " + this.toSql());

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/MultiDistinctSum0.java

@@ -56,7 +56,7 @@ public MultiDistinctSum0(AggregateFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if ((!argType.isNumericType() && !argType.isBooleanType() && !argType.isNullType())
                 || argType.isOnlyMetricType()) {
             throw new AnalysisException("sum0 requires a numeric or boolean parameter: " + this.toSql());

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/PercentileReservoir.java

@@ -67,12 +67,13 @@ private PercentileReservoir(NullableAggregateFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (!getArgument(1).isConstant()) {
+        Expression levelArgument = getArgument(1);
+        if (!levelArgument.isConstant()) {
             throw new AnalysisException(
                     "percentile_reservoir requires second parameter must be a constant : " + this.toSql());
         }
-        if (child(1) instanceof Literal) {
-            double value = ((Literal) child(1)).getDouble();
+        if (levelArgument instanceof Literal) {
+            double value = ((Literal) levelArgument).getDouble();
             if (value < 0 || value > 1) {
                 throw new AnalysisException(
                         "percentile_reservoir level must be in [0, 1], but got " + value + ": " + this.toSql());

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/agg/Sum0.java

@@ -102,7 +102,7 @@ public MultiDistinctSum0 convertToMultiDistinct() {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (!argType.isNumericType() && !argType.isBooleanType()
                 && !argType.isNullType() && !argType.isStringLikeType()) {
             throw new AnalysisException("sum0 requires a numeric, boolean or string parameter: " + this.toSql());

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/generator/ExplodeMap.java

@@ -63,9 +63,10 @@ public ExplodeMap withChildren(List<Expression> children) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (!(child().getDataType() instanceof MapType)) {
+        Expression argument = getArgument(0);
+        if (!(argument.getDataType() instanceof MapType)) {
             throw new AnalysisException("only support map type for explode_map function but got "
-                    + child().getDataType());
+                    + argument.getDataType());
         }
     }
 

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/generator/ExplodeMapOuter.java

@@ -61,9 +61,10 @@ public ExplodeMapOuter withChildren(List<Expression> children) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (!(child().getDataType() instanceof MapType)) {
+        Expression argument = getArgument(0);
+        if (!(argument.getDataType() instanceof MapType)) {
             throw new AnalysisException("only support map type for explode_map function but got "
-                    + child().getDataType());
+                    + argument.getDataType());
         }
     }
 

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Array.java

@@ -69,7 +69,7 @@ public void checkLegalityBeforeTypeCoercion() {
         if (children.isEmpty()) {
             return;
         }
-        DataType firstChildType = children.get(0).getDataType();
+        DataType firstChildType = getArgument(0).getDataType();
         if (firstChildType.isJsonType() || firstChildType.isVariantType()) {
             throw new AnalysisException("array does not support jsonb/variant type");
         }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayApply.java

@@ -87,11 +87,12 @@ private void checkArguments(Expression arg0, Expression arg1, Expression arg2) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (!child(0).getDataType().isArrayType()) {
+        Expression argument = getArgument(0);
+        if (!argument.getDataType().isArrayType()) {
             throw new AnalysisException("array_apply does not support type "
-            + child(0).getDataType() + ", expression is " + toSql());
+            + argument.getDataType() + ", expression is " + toSql());
         }
-        DataType argType = ((ArrayType) child(0).getDataType()).getItemType();
+        DataType argType = ((ArrayType) argument.getDataType()).getItemType();
         if (!(argType.isIntegralType() || argType.isFloatLikeType() || argType.isDecimalLikeType()
                 || argType.isDateLikeType() || argType.isBooleanType())) {
             throw new AnalysisException("array_apply does not support type " + argType + ", expression is " + toSql());

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayAvg.java

@@ -79,10 +79,11 @@ private ArrayAvg(ScalarFunctionParams functionParams) {
      */
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (child(0).getDataType().isArrayType()
-                && !((ArrayType) child(0).getDataType()).getItemType().canBeCalculatedInArray()) {
+        Expression argument = getArgument(0);
+        if (argument.getDataType().isArrayType()
+                && !((ArrayType) argument.getDataType()).getItemType().canBeCalculatedInArray()) {
             throw new AnalysisException("array_avg does not support type "
-                    + child(0).getDataType().toString() + ", expression is " + toSql());
+                    + argument.getDataType().toString() + ", expression is " + toSql());
         }
     }
 

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayCompact.java

@@ -61,7 +61,7 @@ private ArrayCompact(ScalarFunctionParams functionParams) {
      */
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = ((ArrayType) child(0).getDataType()).getItemType();
+        DataType argType = ((ArrayType) getArgument(0).getDataType()).getItemType();
         if (argType.isMapType() || argType.isStructType()) {
             throw new AnalysisException("array_compact does not support type "
             + argType.toString() + ", expression is " + toSql());

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayCumSum.java

@@ -80,10 +80,11 @@ private ArrayCumSum(ScalarFunctionParams functionParams) {
      */
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (child(0).getDataType().isArrayType()
-                && !((ArrayType) child(0).getDataType()).getItemType().canBeCalculatedInArray()) {
+        Expression argument = getArgument(0);
+        if (argument.getDataType().isArrayType()
+                && !((ArrayType) argument.getDataType()).getItemType().canBeCalculatedInArray()) {
             throw new AnalysisException("array_cum_sum does not support type "
-            + child(0).getDataType().toString()
+            + argument.getDataType().toString()
             + ", expression is " + toSql());
         }
     }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayDifference.java

@@ -76,10 +76,11 @@ private ArrayDifference(ScalarFunctionParams functionParams) {
      */
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (child(0).getDataType().isArrayType()
-                && !((ArrayType) child(0).getDataType()).getItemType().canBeCalculatedInArray()) {
+        Expression argument = getArgument(0);
+        if (argument.getDataType().isArrayType()
+                && !((ArrayType) argument.getDataType()).getItemType().canBeCalculatedInArray()) {
             throw new AnalysisException("array_difference does not support type "
-                    + child(0).getDataType().toString() + ", expression is " + toSql());
+                    + argument.getDataType().toString() + ", expression is " + toSql());
         }
     }
 

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayDistinct.java

@@ -61,7 +61,7 @@ private ArrayDistinct(ScalarFunctionParams functionParams) {
      */
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child(0).getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (argType.isArrayType()) {
             DataType itemType = ((ArrayType) argType).getItemType();
             if (itemType.isMapType() || itemType.isStructType()) {

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayEnumerateUniq.java

@@ -65,7 +65,7 @@ private ArrayEnumerateUniq(ScalarFunctionParams functionParams) {
      */
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        for (Expression arg : children()) {
+        for (Expression arg : getArguments()) {
             DataType argType = arg.getDataType();
             if (argType.isArrayType()) {
                 DataType itemType = ((ArrayType) argType).getItemType();

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayIntersect.java

@@ -63,7 +63,7 @@ private ArrayIntersect(ScalarFunctionParams functionParams) {
     @Override
     public void checkLegalityBeforeTypeCoercion() {
         DataType itemType = NullType.INSTANCE;
-        for (Expression child : children()) {
+        for (Expression child : getArguments()) {
             DataType argType = child.getDataType();
             // nullsafe
             if (argType == NullType.INSTANCE) {

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayMax.java

@@ -59,7 +59,7 @@ private ArrayMax(ScalarFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (argType.isArrayType() && ((ArrayType) argType).getItemType().isComplexType()) {
             throw new AnalysisException("array_max does not support complex types: " + toSql());
         }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayMin.java

@@ -59,7 +59,7 @@ private ArrayMin(ScalarFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (argType.isArrayType() && ((ArrayType) argType).getItemType().isComplexType()) {
             throw new AnalysisException("array_min does not support complex types: " + toSql());
         }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayPosition.java

@@ -77,7 +77,7 @@ public ArrayPosition withChildren(List<Expression> children) {
      */
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child(0).getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (argType.isArrayType() && ((ArrayType) argType).getItemType().isComplexType()) {
             throw new AnalysisException("array_position does not support complex types: " + toSql());
         }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayProduct.java

@@ -69,7 +69,7 @@ private ArrayProduct(ScalarFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child().getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (argType instanceof ArrayType && ((ArrayType) argType).getItemType().isComplexType()) {
             throw new AnalysisException(toSql() + " does not support type: "
                                                     + ((ArrayType) argType).getItemType().toString());

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayRemove.java

@@ -72,7 +72,7 @@ public ArrayRemove withChildren(List<Expression> children) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        DataType argType = child(0).getDataType();
+        DataType argType = getArgument(0).getDataType();
         if (argType.isArrayType() && (((ArrayType) argType).getItemType().isComplexType()
                     || ((ArrayType) argType).getItemType().isVariantType()
                     || ((ArrayType) argType).getItemType().isJsonType())) {

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/ArrayReverseSort.java

@@ -57,8 +57,8 @@ private ArrayReverseSort(ScalarFunctionParams functionParams) {
 
     @Override
     public void checkLegalityBeforeTypeCoercion() {
-        if (children.get(0).getDataType() instanceof ArrayType) {
-            DataType argType = child(0).getDataType();
+        DataType argType = getArgument(0).getDataType();
+        if (argType instanceof ArrayType) {
             // Find the innermost element type for nested arrays
             DataType itemType = ((ArrayType) argType).getItemType();
             while (itemType.isArrayType()) {