Add boot4-migration module: one Boot 3.5.16 service migrated to 4.1.2, with the real compile, start-up, silent and test failures captured at each step

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b4VQVEJWetTT1dYzyJ
2026-10-29 05:57:26 +00:00
parent fd0cf9b527
commit 85074ed51a
45 changed files with 1021 additions and 0 deletions
@@ -0,0 +1,11 @@
+package com.ankurm.migration;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class DemoApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(DemoApplication.class, args);
+    }
+}
@@ -0,0 +1,18 @@
+package com.ankurm.migration;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestClient;
+
+/** Takes the auto-configured RestClient.Builder. RestClient itself lives in spring-web, so this always compiles. */
+@Component
+public class Gateway {
+    private final RestClient client;
+
+    public Gateway(RestClient.Builder builder) {
+        this.client = builder.baseUrl("http://localhost:9").build();
+    }
+
+    public String describe() {
+        return client.getClass().getSimpleName();
+    }
+}
@@ -0,0 +1,6 @@
+package com.ankurm.migration;
+
+import java.time.Instant;
+
+public record Greeting(long id, String title, Instant createdAt, String author) {
+}
@@ -0,0 +1,62 @@
+package com.ankurm.migration;
+
+import java.time.Instant;
+import java.util.Map;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class GreetingController {
+
+    private static final Logger log = LoggerFactory.getLogger(GreetingController.class);
+
+    private final GreetingService service;
+    private final JdbcTemplate jdbc;
+    private final Gateway gateway;
+
+    public GreetingController(GreetingService service, JdbcTemplate jdbc, Gateway gateway) {
+        this.service = service;
+        this.jdbc = jdbc;
+        this.gateway = gateway;
+    }
+
+    @GetMapping("/greetings/{id}")
+    public Greeting greeting(@PathVariable long id) {
+        log.info("served greeting {} ........................................", id);
+        return new Greeting(id, service.title(id), Instant.parse("2026-01-02T03:04:05Z"), "ankur");
+    }
+
+    /** Serialised by Jackson's default record handling (no custom serializer). */
+    @GetMapping("/summary")
+    public Summary summary() {
+        Summary s = new Summary();
+        s.setId(1);
+        s.setTitle("Hello");
+        s.setCreatedAt(Instant.parse("2026-01-02T03:04:05Z"));
+        s.setAuthor("ankur");
+        return s;
+    }
+
+    /** Reads the table that the Flyway migration V1 creates. */
+    @GetMapping("/greetings/count")
+    public Map<String, Object> count() {
+        Integer n = jdbc.queryForObject("select count(*) from greeting", Integer.class);
+        return Map.of("rows", n);
+    }
+
+    /** How many times the @Aspect has intercepted GreetingService. */
+    @GetMapping("/aspect")
+    public Map<String, Object> aspect() {
+        return Map.of("interceptions", TimingAspect.COUNT.get());
+    }
+
+    @GetMapping("/gateway")
+    public Map<String, Object> gateway() {
+        return Map.of("client", gateway.describe());
+    }
+}
@@ -0,0 +1,10 @@
+package com.ankurm.migration;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public class GreetingService {
+    public String title(long id) {
+        return "Hello #" + id;
+    }
+}
@@ -0,0 +1,26 @@
+package com.ankurm.migration;
+
+import org.springframework.boot.jackson.JacksonComponent;
+import tools.jackson.core.JacksonException;
+import tools.jackson.core.JsonGenerator;
+import tools.jackson.databind.SerializationContext;
+import tools.jackson.databind.ser.std.StdSerializer;
+
+/** Boot 4: Jackson 3 (tools.jackson), @JacksonComponent, and no checked IOException. */
+@JacksonComponent
+public class JsonConfig extends StdSerializer<Greeting> {
+
+    public JsonConfig() {
+        super(Greeting.class);
+    }
+
+    @Override
+    public void serialize(Greeting g, JsonGenerator gen, SerializationContext ctxt) throws JacksonException {
+        gen.writeStartObject();
+        gen.writeNumberProperty("id", g.id());
+        gen.writeStringProperty("title", g.title());
+        gen.writeStringProperty("createdAt", g.createdAt().toString());
+        gen.writeStringProperty("author", g.author());
+        gen.writeEndObject();
+    }
+}
@@ -0,0 +1,23 @@
+package com.ankurm.migration;
+
+import org.springframework.boot.security.autoconfigure.web.servlet.SecurityFilterProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.Order;
+import org.springframework.security.config.Customizer;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.web.SecurityFilterChain;
+
+@Configuration
+public class SecurityConfig {
+
+    @Bean
+    @Order(SecurityFilterProperties.BASIC_AUTH_ORDER)
+    SecurityFilterChain chain(HttpSecurity http) throws Exception {
+        http.authorizeHttpRequests(a -> a
+                .requestMatchers("/actuator/health/**", "/greetings/**", "/aspect", "/gateway").permitAll()
+                .anyRequest().authenticated())
+            .httpBasic(Customizer.withDefaults());
+        return http.build();
+    }
+}
@@ -0,0 +1,24 @@
+package com.ankurm.migration;
+
+import java.time.Instant;
+
+/**
+ * A plain bean (not a record) whose properties are deliberately NOT in alphabetical order.
+ * Jackson 2 wrote them in declaration order; Jackson 3 sorts bean properties alphabetically by default.
+ * (Records are unaffected: creator parameters are always written first, in constructor order.)
+ */
+public class Summary {
+    private long id;
+    private String title;
+    private Instant createdAt;
+    private String author;
+
+    public long getId() { return id; }
+    public void setId(long id) { this.id = id; }
+    public String getTitle() { return title; }
+    public void setTitle(String title) { this.title = title; }
+    public Instant getCreatedAt() { return createdAt; }
+    public void setCreatedAt(Instant createdAt) { this.createdAt = createdAt; }
+    public String getAuthor() { return author; }
+    public void setAuthor(String author) { this.author = author; }
+}
@@ -0,0 +1,21 @@
+package com.ankurm.migration;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.aspectj.lang.ProceedingJoinPoint;
+import org.aspectj.lang.annotation.Around;
+import org.aspectj.lang.annotation.Aspect;
+import org.springframework.stereotype.Component;
+
+/** Needs AspectJ weaving support on the classpath: spring-boot-starter-aop in Boot 3. */
+@Aspect
+@Component
+public class TimingAspect {
+    static final AtomicInteger COUNT = new AtomicInteger();
+
+    @Around("execution(* com.ankurm.migration.GreetingService.*(..))")
+    public Object count(ProceedingJoinPoint pjp) throws Throwable {
+        COUNT.incrementAndGet();
+        return pjp.proceed();
+    }
+}
@@ -0,0 +1,7 @@
+spring.datasource.url=jdbc:h2:mem:demo;DB_CLOSE_DELAY=-1
+management.endpoints.web.exposure.include=health,metrics
+management.endpoint.health.show-details=always
+logging.file.name=${LOG_DIR:target/logs}/app.log
+# Boot 4.1 removed the old logging.file.* rolling keys; these are the replacements
+logging.logback.rollingpolicy.max-file-size=2KB
+logging.logback.rollingpolicy.max-history=50
@@ -0,0 +1,2 @@
+create table greeting (id bigint primary key, title varchar(100) not null);
+insert into greeting values (1, 'first'), (2, 'second'), (3, 'third');
@@ -0,0 +1,24 @@
+package com.ankurm.migration;
+
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.httpBasic;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.webmvc.test.autoconfigure.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.web.servlet.MockMvc;
+
+/** Prints the status of a Basic-authenticated POST without a CSRF token (to compare 3.5 with 4.1). */
+@SpringBootTest(properties = "spring.security.user.password=pw")
+@AutoConfigureMockMvc
+class CsrfProbeTest {
+
+    @Autowired MockMvc mvc;
+
+    @Test
+    void postWithoutCsrfToken() throws Exception {
+        int status = mvc.perform(post("/anything").with(httpBasic("user", "pw"))).andReturn().getResponse().getStatus();
+        System.out.println("CSRFPROBE status=" + status);
+    }
+}
@@ -0,0 +1,27 @@
+package com.ankurm.migration;
+
+import static org.mockito.BDDMockito.given;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.webmvc.test.autoconfigure.AutoConfigureMockMvc;
+import org.springframework.test.context.bean.override.mockito.MockitoBean;
+import org.springframework.test.web.servlet.MockMvc;
+
+@SpringBootTest
+@AutoConfigureMockMvc
+class GreetingControllerTest {
+
+    @Autowired MockMvc mvc;
+    @MockitoBean GreetingService service;
+
+    @Test
+    void greetingUsesService() throws Exception {
+        given(service.title(7)).willReturn("mocked");
+        mvc.perform(get("/greetings/7")).andExpect(status().isOk()).andExpect(jsonPath("$.title").value("mocked"));
+    }
+}
@@ -0,0 +1,22 @@
+package com.ankurm.migration;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.boot.test.context.SpringBootTest;
+
+/** Boot 4 fix: Mockito's own extension initialises @Mock fields. */
+@SpringBootTest
+@ExtendWith(MockitoExtension.class)
+class MockFieldTest {
+
+    @Mock Runnable task;
+
+    @Test
+    void mockFieldIsInitialised() {
+        assertNotNull(task, "@Mock field was never initialised");
+    }
+}
@@ -0,0 +1,50 @@
+package com.ankurm.migration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.user;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.webmvc.test.autoconfigure.AutoConfigureMockMvc;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.test.web.servlet.MockMvc;
+
+/** Pins the runtime behaviour the "breaks at runtime" checklist is about, so a regression fails the build. */
+@SpringBootTest
+@AutoConfigureMockMvc
+class RuntimeFactsTest {
+
+    @Autowired MockMvc mvc;
+    @Autowired JdbcTemplate jdbc;
+
+    @Test
+    void flywayMigrationRan() {
+        assertThat(jdbc.queryForObject("select count(*) from greeting", Integer.class)).isEqualTo(3);
+    }
+
+    @Test
+    void aspectIntercepts() throws Exception {
+        mvc.perform(get("/greetings/1")).andExpect(status().isOk());
+        assertThat(TimingAspect.COUNT.get()).isPositive();
+    }
+
+    @Test
+    void restClientBuilderIsAutoConfigured() throws Exception {
+        mvc.perform(get("/gateway")).andExpect(status().isOk());
+    }
+
+    @Test
+    void metricsEndpointExists() throws Exception {
+        mvc.perform(get("/actuator/metrics").with(user("u")))
+                .andExpect(status().isOk());
+    }
+
+    @Test
+    void serializerIsTheJacksonComponent() throws Exception {
+        mvc.perform(get("/greetings/2")).andExpect(content().json("{\"id\":2,\"title\":\"Hello #2\"}"));
+    }
+}