Propagate resolvedName to getDefaultValue and pass it to handleMissin…

…gValue and handleNullValue to improve error message

Prior to this commit when an error occurred related to a property or expression placeholder, the exception thrown would refer to the placeholder instead of the resolved name.

See gh-32323

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractNamedValueArgumentResolver.java

@@ -119,7 +119,7 @@ public Mono<Object> resolveArgument(
 					return Mono.justOrEmpty(arg);
 				})
 				.switchIfEmpty(getDefaultValue(
-						namedValueInfo, parameter, bindingContext, model, exchange));
+						namedValueInfo, resolvedName.toString(), parameter, bindingContext, model, exchange));
 	}
 
 	/**
@@ -218,7 +218,7 @@ private Object applyConversion(@Nullable Object value, NamedValueInfo namedValue
 	/**
 	 * Resolve the default value, if any.
 	 */
-	private Mono<Object> getDefaultValue(NamedValueInfo namedValueInfo, MethodParameter parameter,
+	private Mono<Object> getDefaultValue(NamedValueInfo namedValueInfo, String resolvedName, MethodParameter parameter,
 			BindingContext bindingContext, Model model, ServerWebExchange exchange) {
 
 		return Mono.fromSupplier(() -> {
@@ -230,10 +230,10 @@ private Mono<Object> getDefaultValue(NamedValueInfo namedValueInfo, MethodParame
 				value = resolveEmbeddedValuesAndExpressions(namedValueInfo.defaultValue);
 			}
 			else if (namedValueInfo.required && !parameter.isOptional()) {
-				handleMissingValue(namedValueInfo.name, parameter, exchange);
+				handleMissingValue(resolvedName, parameter, exchange);
 			}
 			if (!hasDefaultValue) {
-				value = handleNullValue(namedValueInfo.name, value, parameter.getNestedParameterType());
+				value = handleNullValue(resolvedName, value, parameter.getNestedParameterType());
 			}
 			if (value != null || !hasDefaultValue) {
 				value = applyConversion(value, namedValueInfo, parameter, bindingContext, exchange);

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestHeaderMethodArgumentResolverTests.java

@@ -36,13 +36,15 @@
 import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
 import org.springframework.web.reactive.BindingContext;
+import org.springframework.web.server.MissingRequestValueException;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.ServerWebInputException;
 import org.springframework.web.testfixture.http.server.reactive.MockServerHttpRequest;
 import org.springframework.web.testfixture.server.MockServerWebExchange;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /**
  * Tests for {@link RequestHeaderMethodArgumentResolver}.
@@ -64,6 +66,7 @@ class RequestHeaderMethodArgumentResolverTests {
 	private MethodParameter paramDate;
 	private MethodParameter paramInstant;
 	private MethodParameter paramMono;
+	private MethodParameter primitivePlaceholderParam;
 
 
 	@BeforeEach
@@ -87,6 +90,7 @@ void setup() throws Exception {
 		this.paramDate = new SynthesizingMethodParameter(method, 6);
 		this.paramInstant = new SynthesizingMethodParameter(method, 7);
 		this.paramMono = new SynthesizingMethodParameter(method, 8);
+		this.primitivePlaceholderParam = new SynthesizingMethodParameter(method, 9);
 	}
 
 
@@ -200,6 +204,46 @@ void resolveNameFromSystemPropertyThroughPlaceholder() {
 		}
 	}
 
+	@Test
+	void missingParameterFromSystemPropertyThroughPlaceholder() {
+		String expected = "sysbar";
+		MockServerHttpRequest request = MockServerHttpRequest.get("/").build();
+		ServerWebExchange exchange = MockServerWebExchange.from(request);
+
+		System.setProperty("systemProperty", expected);
+		try {
+			Mono<Object> mono = this.resolver.resolveArgument(
+					this.paramResolvedNameWithExpression, this.bindingContext, exchange);
+
+			assertThatThrownBy(() -> mono.block())
+					.isInstanceOf(MissingRequestValueException.class)
+					.extracting("name").isEqualTo(expected);
+		}
+		finally {
+			System.clearProperty("systemProperty");
+		}
+	}
+
+	@Test
+	void notNullablePrimitiveParameterFromSystemPropertyThroughPlaceholder() {
+		String expected = "sysbar";
+		MockServerHttpRequest request = MockServerHttpRequest.get("/").build();
+		ServerWebExchange exchange = MockServerWebExchange.from(request);
+
+		System.setProperty("systemProperty", expected);
+		try {
+			Mono<Object> mono = this.resolver.resolveArgument(
+					this.primitivePlaceholderParam, this.bindingContext, exchange);
+
+			assertThatThrownBy(() -> mono.block())
+					.isInstanceOf(IllegalStateException.class)
+					.hasMessageContaining(expected);
+		}
+		finally {
+			System.clearProperty("systemProperty");
+		}
+	}
+
 	@Test
 	void notFound() {
 		Mono<Object> mono = resolver.resolveArgument(
@@ -252,7 +296,8 @@ public void params(
 			@RequestHeader("name") Map<?, ?> unsupported,
 			@RequestHeader("name") Date dateParam,
 			@RequestHeader("name") Instant instantParam,
-			@RequestHeader Mono<String> alsoNotSupported) {
+			@RequestHeader Mono<String> alsoNotSupported,
+			@RequestHeader(value = "${systemProperty}", required = false) int primitivePlaceholderParam) {
 	}
 
 }