[HUDI-5589] Fix Hudi config inference

hudi-common/src/main/java/org/apache/hudi/common/config/HoodieConfig.java

@@ -70,7 +70,13 @@ public <T> void setDefaultValue(ConfigProperty<T> configProperty) {
       if (configProperty.getInferFunc().isPresent()) {
         inferValue = configProperty.getInferFunc().get().apply(this);
       }
-      props.setProperty(configProperty.key(), inferValue.isPresent() ? inferValue.get().toString() : configProperty.defaultValue().toString());
+      if (inferValue.isPresent() || configProperty.hasDefaultValue()) {
+        props.setProperty(
+            configProperty.key(),
+            inferValue.isPresent()
+                ? inferValue.get().toString()
+                : configProperty.defaultValue().toString());
+      }
     }
   }
 
@@ -114,7 +120,7 @@ protected void setDefaults(String configClassName) {
         .forEach(f -> {
           try {
             ConfigProperty<?> cfgProp = (ConfigProperty<?>) f.get("null");
-            if (cfgProp.hasDefaultValue()) {
+            if (cfgProp.hasDefaultValue() || cfgProp.getInferFunc().isPresent()) {
               setDefaultValue(cfgProp);
             }
           } catch (IllegalAccessException e) {

hudi-common/src/test/java/org/apache/hudi/common/config/HoodieTestFakeConfig.java

@@ -0,0 +1,96 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.hudi.common.config;
+
+import java.util.Properties;
+
+/**
+ * A config class extending {@link HoodieConfig} for testing only.
+ */
+public class HoodieTestFakeConfig extends HoodieConfig {
+
+  public static ConfigProperty<String> FAKE_STRING_CONFIG = TestConfigProperty.FAKE_STRING_CONFIG;
+  public static ConfigProperty<Integer> FAKE_INTEGER_CONFIG = TestConfigProperty.FAKE_INTEGER_CONFIG;
+  public static ConfigProperty<String> FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER
+      = TestConfigProperty.FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER;
+  public static ConfigProperty<String> FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY
+      = TestConfigProperty.FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY;
+
+  private HoodieTestFakeConfig() {
+    super();
+  }
+
+  private HoodieTestFakeConfig(Properties props) {
+    super(props);
+  }
+
+  public String getFakeString() {
+    return getString(FAKE_STRING_CONFIG);
+  }
+
+  public int getFakeInteger() {
+    return getInt(FAKE_INTEGER_CONFIG);
+  }
+
+  public String getFakeStringNoDefaultWithInfer() {
+    return getString(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER);
+  }
+
+  public String getFakeStringNoDefaultWithInferEmpty() {
+    return getString(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY);
+  }
+
+  public static HoodieTestFakeConfig.Builder newBuilder() {
+    return new Builder();
+  }
+
+  public static class Builder {
+    private final HoodieTestFakeConfig config = new HoodieTestFakeConfig();
+
+    public Builder withFakeString(String value) {
+      config.setValue(FAKE_STRING_CONFIG, value);
+      return this;
+    }
+
+    public Builder withFakeInteger(int value) {
+      config.setValue(FAKE_INTEGER_CONFIG, String.valueOf(value));
+      return this;
+    }
+
+    public Builder withFakeStringNoDefaultWithInfer(String value) {
+      config.setValue(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER, value);
+      return this;
+    }
+
+    public Builder withFakeStringNoDefaultWithInferEmpty(String value) {
+      config.setValue(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY, value);
+      return this;
+    }
+
+    public HoodieTestFakeConfig build() {
+      setDefaults();
+      return new HoodieTestFakeConfig(config.getProps());
+    }
+
+    private void setDefaults() {
+      config.setDefaults(HoodieTestFakeConfig.class.getName());
+    }
+  }
+}

hudi-common/src/test/java/org/apache/hudi/common/config/TestConfigProperty.java

@@ -60,6 +60,29 @@ public class TestConfigProperty extends HoodieConfig {
       })
       .withDocumentation("Fake config only for testing");
 
+  public static ConfigProperty<String> FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER = ConfigProperty
+      .key("test.fake.string.config.no_default_with_infer")
+      .noDefaultValue()
+      .withInferFunction(p -> {
+        if (p.getStringOrDefault(FAKE_STRING_CONFIG).equals("value1")) {
+          return Option.of("value2");
+        }
+        return Option.of("value3");
+      })
+      .withDocumentation("Fake config with infer function and without default only for testing");
+
+  public static ConfigProperty<String> FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY = ConfigProperty
+      .key("test.fake.string.config.no_default_with_infer_empty")
+      .noDefaultValue()
+      .withInferFunction(p -> {
+        if (p.getStringOrDefault(FAKE_STRING_CONFIG).equals("value1")) {
+          return Option.of("value10");
+        }
+        return Option.empty();
+      })
+      .withDocumentation("Fake config with infer function that ca return empty value "
+          + "and without default only for testing");
+
   @Test
   public void testGetTypedValue() {
     HoodieConfig hoodieConfig = new HoodieConfig();
@@ -112,11 +135,30 @@ public void testInference() {
     hoodieConfig2.setValue(FAKE_STRING_CONFIG, "5");
     hoodieConfig2.setDefaultValue(FAKE_INTEGER_CONFIG);
     assertEquals(100, hoodieConfig2.getInt(FAKE_INTEGER_CONFIG));
+
+    HoodieConfig hoodieConfig3 = new HoodieConfig();
+    hoodieConfig3.setValue(FAKE_STRING_CONFIG, "value1");
+    hoodieConfig3.setDefaultValue(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER);
+    hoodieConfig3.setDefaultValue(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY);
+    assertEquals("value2", hoodieConfig3.getString(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER));
+    assertEquals("value10", hoodieConfig3.getString(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY));
+
+    HoodieConfig hoodieConfig4 = new HoodieConfig();
+    hoodieConfig4.setValue(FAKE_STRING_CONFIG, "other");
+    hoodieConfig4.setDefaultValue(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER);
+    assertEquals("value3", hoodieConfig4.getString(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER));
+    assertEquals(null, hoodieConfig4.getString(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY));
+
+    HoodieConfig hoodieConfig5 = new HoodieConfig();
+    hoodieConfig5.setValue(FAKE_STRING_CONFIG, "other");
+    hoodieConfig5.setValue(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER, "value4");
+    hoodieConfig5.setDefaultValue(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER);
+    assertEquals("value4", hoodieConfig5.getString(FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER));
   }
 
   @Test
   public void testSetDefaults() {
     setDefaults(this.getClass().getName());
-    assertEquals(3, getProps().size());
+    assertEquals(4, getProps().size());
   }
 }

hudi-common/src/test/java/org/apache/hudi/common/config/TestHoodieConfig.java

@@ -0,0 +1,70 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.hudi.common.config;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Tests {@link HoodieConfig}.
+ */
+public class TestHoodieConfig {
+  @Test
+  public void testHoodieConfig() {
+    // Case 1: defaults and infer function are used
+    HoodieTestFakeConfig config1 = HoodieTestFakeConfig.newBuilder().build();
+    assertEquals("1", config1.getFakeString());
+    assertEquals(0, config1.getFakeInteger());
+    assertEquals("value3", config1.getFakeStringNoDefaultWithInfer());
+    assertEquals(null, config1.getFakeStringNoDefaultWithInferEmpty());
+
+    // Case 2: FAKE_STRING_CONFIG is set.  FAKE_INTEGER_CONFIG,
+    // FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER, and
+    // FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY are inferred
+    HoodieTestFakeConfig config2 = HoodieTestFakeConfig.newBuilder()
+        .withFakeString("value1").build();
+    assertEquals("value1", config2.getFakeString());
+    assertEquals(0, config2.getFakeInteger());
+    assertEquals("value2", config2.getFakeStringNoDefaultWithInfer());
+    assertEquals("value10", config2.getFakeStringNoDefaultWithInferEmpty());
+
+    // Case 3: FAKE_STRING_CONFIG is set to a different value.  FAKE_INTEGER_CONFIG,
+    // FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER, and
+    // FAKE_STRING_CONFIG_NO_DEFAULT_WITH_INFER_EMPTY are inferred
+    HoodieTestFakeConfig config3 = HoodieTestFakeConfig.newBuilder()
+        .withFakeString("5").build();
+    assertEquals("5", config3.getFakeString());
+    assertEquals(100, config3.getFakeInteger());
+    assertEquals("value3", config3.getFakeStringNoDefaultWithInfer());
+    assertEquals(null, config3.getFakeStringNoDefaultWithInferEmpty());
+
+    // Case 4: all configs are set.  No default or infer function should be used
+    HoodieTestFakeConfig config4 = HoodieTestFakeConfig.newBuilder()
+        .withFakeString("5")
+        .withFakeInteger(200)
+        .withFakeStringNoDefaultWithInfer("xyz")
+        .withFakeStringNoDefaultWithInferEmpty("uvw").build();
+    assertEquals("5", config4.getFakeString());
+    assertEquals(200, config4.getFakeInteger());
+    assertEquals("xyz", config4.getFakeStringNoDefaultWithInfer());
+    assertEquals("uvw", config4.getFakeStringNoDefaultWithInferEmpty());
+  }
+}