[fix](Nereids) only search internal funcftion when dbName is empty

fe/fe-core/src/main/java/org/apache/doris/catalog/FunctionRegistry.java

@@ -33,6 +33,7 @@
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import org.apache.commons.collections.CollectionUtils;
+import org.apache.commons.lang3.StringUtils;
 
 import java.util.List;
 import java.util.Map;
@@ -86,24 +87,31 @@ public Optional<List<FunctionBuilder>> tryGetBuiltinBuilders(String name) {
 
     // currently we only find function by name and arity and args' types.
     public FunctionBuilder findFunctionBuilder(String dbName, String name, List<?> arguments) {
+        List<FunctionBuilder> functionBuilders = null;
         int arity = arguments.size();
-        List<FunctionBuilder> functionBuilders = name2InternalBuiltinBuilders.get(name.toLowerCase());
-        if (CollectionUtils.isEmpty(functionBuilders) && AggStateFunctionBuilder.isAggStateCombinator(name)) {
-            String nestedName = AggStateFunctionBuilder.getNestedName(name);
-            String combinatorSuffix = AggStateFunctionBuilder.getCombinatorSuffix(name);
-
-            functionBuilders = name2InternalBuiltinBuilders.get(nestedName.toLowerCase());
-
-            if (functionBuilders != null) {
-                functionBuilders = functionBuilders.stream().map(builder -> {
-                    return new AggStateFunctionBuilder(combinatorSuffix, builder);
-                }).filter(functionBuilder -> functionBuilder.canApply(arguments)).collect(Collectors.toList());
+        String qualifiedName = StringUtils.isEmpty(dbName) ? name : dbName + "." + name;
+
+        if (StringUtils.isEmpty(dbName)) {
+            // search internal function only if dbName is empty
+            functionBuilders = name2InternalBuiltinBuilders.get(name.toLowerCase());
+            if (CollectionUtils.isEmpty(functionBuilders) && AggStateFunctionBuilder.isAggStateCombinator(name)) {
+                String nestedName = AggStateFunctionBuilder.getNestedName(name);
+                String combinatorSuffix = AggStateFunctionBuilder.getCombinatorSuffix(name);
+                functionBuilders = name2InternalBuiltinBuilders.get(nestedName.toLowerCase());
+                if (functionBuilders != null) {
+                    functionBuilders = functionBuilders.stream()
+                            .map(builder -> new AggStateFunctionBuilder(combinatorSuffix, builder))
+                            .filter(functionBuilder -> functionBuilder.canApply(arguments))
+                            .collect(Collectors.toList());
+                }
             }
         }
-        if (functionBuilders == null || functionBuilders.isEmpty()) {
+
+        // search udf
+        if (CollectionUtils.isEmpty(functionBuilders)) {
             functionBuilders = findUdfBuilder(dbName, name);
             if (functionBuilders == null || functionBuilders.isEmpty()) {
-                throw new AnalysisException("Can not found function '" + name + "'");
+                throw new AnalysisException("Can not found function '" + qualifiedName + "'");
             }
         }
 
@@ -113,15 +121,15 @@ public FunctionBuilder findFunctionBuilder(String dbName, String name, List<?> a
                 .collect(Collectors.toList());
         if (candidateBuilders.isEmpty()) {
             String candidateHints = getCandidateHint(name, functionBuilders);
-            throw new AnalysisException("Can not found function '" + name
+            throw new AnalysisException("Can not found function '" + qualifiedName
                     + "' which has " + arity + " arity. Candidate functions are: " + candidateHints);
         }
-
         if (candidateBuilders.size() > 1) {
             String candidateHints = getCandidateHint(name, candidateBuilders);
             // NereidsPlanner not supported override function by the same arity, should we support it?
-            throw new AnalysisException("Function '" + name + "' is ambiguous: " + candidateHints);
+            throw new AnalysisException("Function '" + qualifiedName + "' is ambiguous: " + candidateHints);
         }
+
         return candidateBuilders.get(0);
     }
 

fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FunctionBinder.java

@@ -59,6 +59,7 @@
 import org.apache.doris.nereids.util.TypeCoercionUtils;
 
 import com.google.common.collect.ImmutableList;
+import org.apache.commons.lang3.StringUtils;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -142,22 +143,24 @@ public Expression visitUnboundFunction(UnboundFunction unboundFunction, Expressi
 
         // bind function
         FunctionRegistry functionRegistry = Env.getCurrentEnv().getFunctionRegistry();
-        String functionName = unboundFunction.getName();
         List<Object> arguments = unboundFunction.isDistinct()
                 ? ImmutableList.builder()
                 .add(unboundFunction.isDistinct())
                 .addAll(unboundFunction.getArguments())
                 .build()
                 : (List) unboundFunction.getArguments();
 
-        // we will change arithmetic function like add(), subtract(), bitnot() to the corresponding objects rather than
-        // BoundFunction.
-        ArithmeticFunctionBinder functionBinder = new ArithmeticFunctionBinder();
-        if (functionBinder.isBinaryArithmetic(unboundFunction.getName())) {
-            return functionBinder.bindBinaryArithmetic(unboundFunction.getName(), unboundFunction.children())
-                    .accept(this, context);
+        if (StringUtils.isEmpty(unboundFunction.getDbName())) {
+            // we will change arithmetic function like add(), subtract(), bitnot()
+            // to the corresponding objects rather than BoundFunction.
+            ArithmeticFunctionBinder functionBinder = new ArithmeticFunctionBinder();
+            if (functionBinder.isBinaryArithmetic(unboundFunction.getName())) {
+                return functionBinder.bindBinaryArithmetic(unboundFunction.getName(), unboundFunction.children())
+                        .accept(this, context);
+            }
         }
 
+        String functionName = unboundFunction.getName();
         FunctionBuilder builder = functionRegistry.findFunctionBuilder(
                 unboundFunction.getDbName(), functionName, arguments);
         if (builder instanceof AliasUdfBuilder) {

regression-test/suites/nereids_syntax_p0/function.groovy

@@ -189,5 +189,10 @@ suite("nereids_function") {
     qt_regexp_extract_all """
         SELECT regexp_extract_all('AbCdE', '([[:lower:]]+)C([[:lower:]]+)')
     """
+
+    test {
+        sql "select `hello`.now(3)"
+        exception "Can not found function"
+    }
 }