Add openrewrite module: Boot 2.7 to 3.5 to 4.0 upgrade with OpenRewrite recipes, leftovers and CI gate

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Gth99spB1CzQmBFofXmU4Z

openrewrite/README.md

@@ -0,0 +1,27 @@
+# openrewrite
+
+Companion module for the ankurm.com post *Automating javax → jakarta and Boot 3 → 4 Upgrades with OpenRewrite*.
+
+`legacy-app/` is a small Spring Boot 2.7.18 application (JPA, validation, security, a servlet filter, `RestTemplate`, a JUnit 4 test, a `spring.factories` auto-configuration). `scripts/run-all.sh` copies it to a scratch directory outside this checkout, runs two OpenRewrite recipes in sequence, builds and tests after each, and records everything under `output/`.
+
+| Tool | Version |
+|---|---|
+| rewrite-maven-plugin | 6.46.1 |
+| rewrite-spring | 6.37.1 |
+| rewrite-migrate-java | 3.42.1 |
+| JDK / Maven | 17 / 3.9 |
+
+```bash
+export JAVA_HOME=/path/to/jdk17
+./scripts/run-all.sh
+```
+
+| Output | Shows |
+|---|---|
+| `00-gotcha-gitignore.txt` | OpenRewrite silently skips sources that git ignores |
+| `01-baseline.txt` | Legacy app builds and passes on Boot 2.7.18 |
+| `02-step1-diff.txt` / `03-step1-build.txt` | `UpgradeSpringBoot_3_5`: diff and build |
+| `04-step2-diff.txt` / `05-step2-build.txt` | `UpgradeSpringBoot_4_0`: diff and build |
+| `06-what-it-left-behind.txt` | What the recipes did not change |
+| `07-step3-boot-4.1.1.txt` | Hand bump from 4.0.x to 4.1.1, build and test |
+| `08-ci-gate.txt` | `rewrite:dryRun` exit codes, including a property-name trap |

openrewrite/legacy-app/pom.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.springframework.boot</groupId>
+    <artifactId>spring-boot-starter-parent</artifactId>
+    <version>2.7.18</version>
+    <relativePath/>
+  </parent>
+  <groupId>com.ankurm</groupId>
+  <artifactId>legacy-app</artifactId>
+  <version>1.0.0</version>
+  <properties>
+    <java.version>17</java.version>
+  </properties>
+  <dependencies>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-validation</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-security</artifactId></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency>
+    <dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency>
+    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
+    <dependency><groupId>org.junit.vintage</groupId><artifactId>junit-vintage-engine</artifactId><scope>test</scope></dependency>
+    <dependency><groupId>org.springframework.security</groupId><artifactId>spring-security-test</artifactId><scope>test</scope></dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin>
+    </plugins>
+  </build>
+</project>

openrewrite/legacy-app/src/main/java/com/ankurm/legacy/AuditAutoConfiguration.java

@@ -0,0 +1,7 @@
+package com.ankurm.legacy;
+
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class AuditAutoConfiguration {
+}

openrewrite/legacy-app/src/main/java/com/ankurm/legacy/Customer.java

@@ -0,0 +1,26 @@
+package com.ankurm.legacy;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.validation.constraints.Email;
+import javax.validation.constraints.NotBlank;
+
+@Entity
+public class Customer {
+	@Id
+	@GeneratedValue
+	private Long id;
+	@NotBlank
+	private String name;
+	@Email
+	private String email;
+
+	protected Customer() {}
+	public Customer(String name, String email) { this.name = name; this.email = email; }
+	public Long getId() { return id; }
+	public String getName() { return name; }
+	public String getEmail() { return email; }
+	public void setName(String name) { this.name = name; }
+	public void setEmail(String email) { this.email = email; }
+}

openrewrite/legacy-app/src/main/java/com/ankurm/legacy/CustomerController.java

@@ -0,0 +1,28 @@
+package com.ankurm.legacy;
+
+import java.util.List;
+import javax.annotation.PostConstruct;
+import javax.validation.Valid;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/customers")
+public class CustomerController {
+
+	private final CustomerRepository repository;
+
+	public CustomerController(CustomerRepository repository) { this.repository = repository; }
+
+	@PostConstruct
+	void seed() {
+		repository.save(new Customer("Ada", "[email protected]"));
+	}
+
+	@GetMapping
+	List<Customer> all() { return repository.findAll(); }
+
+	@PostMapping
+	@ResponseStatus(HttpStatus.CREATED)
+	Customer create(@Valid @RequestBody Customer c) { return repository.save(c); }
+}

openrewrite/legacy-app/src/main/java/com/ankurm/legacy/CustomerRepository.java

@@ -0,0 +1,14 @@
+package com.ankurm.legacy;
+
+import javax.persistence.LockModeType;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Lock;
+import org.springframework.data.jpa.repository.QueryHints;
+import javax.persistence.QueryHint;
+
+public interface CustomerRepository extends JpaRepository<Customer, Long> {
+
+	@Lock(LockModeType.PESSIMISTIC_WRITE)
+	@QueryHints(@QueryHint(name = "javax.persistence.lock.timeout", value = "3000"))
+	Customer findFirstByName(String name);
+}

openrewrite/legacy-app/src/main/java/com/ankurm/legacy/LegacyApplication.java

@@ -0,0 +1,11 @@
+package com.ankurm.legacy;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class LegacyApplication {
+	public static void main(String[] args) {
+		SpringApplication.run(LegacyApplication.class, args);
+	}
+}

openrewrite/legacy-app/src/main/java/com/ankurm/legacy/RemoteClient.java

@@ -0,0 +1,13 @@
+package com.ankurm.legacy;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestTemplate;
+
+@Component
+public class RemoteClient {
+	private final RestTemplate rest = new RestTemplate();
+
+	public String fetch(String url) {
+		return rest.getForObject(url, String.class);
+	}
+}

openrewrite/legacy-app/src/main/java/com/ankurm/legacy/RequestLogFilter.java

@@ -0,0 +1,19 @@
+package com.ankurm.legacy;
+
+import java.io.IOException;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import org.springframework.stereotype.Component;
+import org.springframework.web.filter.OncePerRequestFilter;
+
+@Component
+public class RequestLogFilter extends OncePerRequestFilter {
+	@Override
+	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
+			throws ServletException, IOException {
+		response.setHeader("X-Seen-By", "RequestLogFilter");
+		chain.doFilter(request, response);
+	}
+}

openrewrite/legacy-app/src/main/java/com/ankurm/legacy/SecurityConfig.java

@@ -0,0 +1,17 @@
+package com.ankurm.legacy;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+
+@Configuration
+@EnableWebSecurity
+public class SecurityConfig extends WebSecurityConfigurerAdapter {
+	@Override
+	protected void configure(HttpSecurity http) throws Exception {
+		http.csrf().disable()
+			.authorizeRequests().antMatchers("/actuator/health").permitAll()
+			.anyRequest().permitAll();
+	}
+}

openrewrite/legacy-app/src/main/resources/META-INF/spring.factories

@@ -0,0 +1 @@
+org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.ankurm.legacy.AuditAutoConfiguration

openrewrite/legacy-app/src/main/resources/application.properties

@@ -0,0 +1,6 @@
+spring.redis.host=localhost
+spring.redis.port=6379
+management.metrics.export.prometheus.enabled=true
+spring.jpa.hibernate.ddl-auto=create-drop
+server.max-http-header-size=16KB
+spring.jpa.properties.javax.persistence.validation.mode=none

openrewrite/legacy-app/src/test/java/com/ankurm/legacy/CustomerControllerTest.java

@@ -0,0 +1,26 @@
+package com.ankurm.legacy;
+
+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.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@AutoConfigureMockMvc
+public class CustomerControllerTest {
+
+	@Autowired MockMvc mvc;
+
+	@Test
+	public void listsSeededCustomer() throws Exception {
+		mvc.perform(get("/customers")).andExpect(status().isOk()).andExpect(jsonPath("$[0].name").value("Ada"));
+	}
+}

openrewrite/output/00-gotcha-gitignore.txt

@@ -0,0 +1,3 @@
+# 00-gotcha-gitignore: same recipe, same project, sources under a .gitignore'd directory
+[INFO] Project [legacy-app] Parsing source files
+[INFO] Applying recipes would make no changes. No patch file generated.

openrewrite/output/01-baseline.txt

@@ -0,0 +1,3 @@
+# 01-baseline: legacy app, Spring Boot 2.7.18, JDK 17
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
+[INFO] BUILD SUCCESS

openrewrite/output/02-step1-diff.txt

@@ -0,0 +1,173 @@
+# 02-step1-diff: recipe org.openrewrite.java.spring.boot3.UpgradeSpringBoot_3_5 on the legacy app (52 s)
+diff -ru -x target legacy-app/pom.xml step1/pom.xml
+--- legacy-app/pom.xml
++++ step1/pom.xml
+@@ -4,7 +4,7 @@
+   <parent>
+     <groupId>org.springframework.boot</groupId>
+     <artifactId>spring-boot-starter-parent</artifactId>
+-    <version>2.7.18</version>
++    <version>3.5.16</version>
+     <relativePath/>
+   </parent>
+   <groupId>com.ankurm</groupId>
+@@ -14,6 +14,10 @@
+     <java.version>17</java.version>
+   </properties>
+   <dependencies>
++    <dependency>
++      <groupId>jakarta.servlet</groupId>
++      <artifactId>jakarta.servlet-api</artifactId>
++    </dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-validation</artifactId></dependency>
+@@ -21,7 +25,6 @@
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency>
+     <dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
+-    <dependency><groupId>org.junit.vintage</groupId><artifactId>junit-vintage-engine</artifactId><scope>test</scope></dependency>
+     <dependency><groupId>org.springframework.security</groupId><artifactId>spring-security-test</artifactId><scope>test</scope></dependency>
+   </dependencies>
+   <build>
+diff -ru -x target legacy-app/src/main/java/com/ankurm/legacy/AuditAutoConfiguration.java step1/src/main/java/com/ankurm/legacy/AuditAutoConfiguration.java
+--- legacy-app/src/main/java/com/ankurm/legacy/AuditAutoConfiguration.java
++++ step1/src/main/java/com/ankurm/legacy/AuditAutoConfiguration.java
+@@ -1,7 +1,7 @@
+ package com.ankurm.legacy;
+ 
+-import org.springframework.context.annotation.Configuration;
++import org.springframework.boot.autoconfigure.AutoConfiguration;
+ 
+-@Configuration
++@AutoConfiguration
+ public class AuditAutoConfiguration {
+ }
+diff -ru -x target legacy-app/src/main/java/com/ankurm/legacy/Customer.java step1/src/main/java/com/ankurm/legacy/Customer.java
+--- legacy-app/src/main/java/com/ankurm/legacy/Customer.java
++++ step1/src/main/java/com/ankurm/legacy/Customer.java
+@@ -1,10 +1,10 @@
+ package com.ankurm.legacy;
+ 
+-import javax.persistence.Entity;
+-import javax.persistence.GeneratedValue;
+-import javax.persistence.Id;
+-import javax.validation.constraints.Email;
+-import javax.validation.constraints.NotBlank;
++import jakarta.persistence.Entity;
++import jakarta.persistence.GeneratedValue;
++import jakarta.persistence.Id;
++import jakarta.validation.constraints.Email;
++import jakarta.validation.constraints.NotBlank;
+ 
+ @Entity
+ public class Customer {
+diff -ru -x target legacy-app/src/main/java/com/ankurm/legacy/CustomerController.java step1/src/main/java/com/ankurm/legacy/CustomerController.java
+--- legacy-app/src/main/java/com/ankurm/legacy/CustomerController.java
++++ step1/src/main/java/com/ankurm/legacy/CustomerController.java
+@@ -1,8 +1,8 @@
+ package com.ankurm.legacy;
+ 
+ import java.util.List;
+-import javax.annotation.PostConstruct;
+-import javax.validation.Valid;
++import jakarta.annotation.PostConstruct;
++import jakarta.validation.Valid;
+ import org.springframework.http.HttpStatus;
+ import org.springframework.web.bind.annotation.*;
+ 
+diff -ru -x target legacy-app/src/main/java/com/ankurm/legacy/CustomerRepository.java step1/src/main/java/com/ankurm/legacy/CustomerRepository.java
+--- legacy-app/src/main/java/com/ankurm/legacy/CustomerRepository.java
++++ step1/src/main/java/com/ankurm/legacy/CustomerRepository.java
+@@ -1,10 +1,10 @@
+ package com.ankurm.legacy;
+ 
+-import javax.persistence.LockModeType;
++import jakarta.persistence.LockModeType;
+ import org.springframework.data.jpa.repository.JpaRepository;
+ import org.springframework.data.jpa.repository.Lock;
+ import org.springframework.data.jpa.repository.QueryHints;
+-import javax.persistence.QueryHint;
++import jakarta.persistence.QueryHint;
+ 
+ public interface CustomerRepository extends JpaRepository<Customer, Long> {
+ 
+diff -ru -x target legacy-app/src/main/java/com/ankurm/legacy/RequestLogFilter.java step1/src/main/java/com/ankurm/legacy/RequestLogFilter.java
+--- legacy-app/src/main/java/com/ankurm/legacy/RequestLogFilter.java
++++ step1/src/main/java/com/ankurm/legacy/RequestLogFilter.java
+@@ -1,10 +1,10 @@
+ package com.ankurm.legacy;
+ 
+ import java.io.IOException;
+-import javax.servlet.FilterChain;
+-import javax.servlet.ServletException;
+-import javax.servlet.http.HttpServletRequest;
+-import javax.servlet.http.HttpServletResponse;
++import jakarta.servlet.FilterChain;
++import jakarta.servlet.ServletException;
++import jakarta.servlet.http.HttpServletRequest;
++import jakarta.servlet.http.HttpServletResponse;
+ import org.springframework.stereotype.Component;
+ import org.springframework.web.filter.OncePerRequestFilter;
+ 
+diff -ru -x target legacy-app/src/main/java/com/ankurm/legacy/SecurityConfig.java step1/src/main/java/com/ankurm/legacy/SecurityConfig.java
+--- legacy-app/src/main/java/com/ankurm/legacy/SecurityConfig.java
++++ step1/src/main/java/com/ankurm/legacy/SecurityConfig.java
+@@ -1,17 +1,19 @@
+ package com.ankurm.legacy;
+ 
++import org.springframework.context.annotation.Bean;
+ import org.springframework.context.annotation.Configuration;
+ import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+ import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+-import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
++import org.springframework.security.web.SecurityFilterChain;
+ 
+ @Configuration
+ @EnableWebSecurity
+-public class SecurityConfig extends WebSecurityConfigurerAdapter {
+-	@Override
+-	protected void configure(HttpSecurity http) throws Exception {
+-		http.csrf().disable()
+-			.authorizeRequests().antMatchers("/actuator/health").permitAll()
+-			.anyRequest().permitAll();
++public class SecurityConfig {
++	@Bean
++	SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
++		http.csrf(csrf -> csrf.disable())
++			.authorizeHttpRequests(requests -> requests.requestMatchers("/actuator/health").permitAll()
++				.anyRequest().permitAll());
++		return http.build();
+ 	}
+ }
+Only in step1/src/main/resources/META-INF: spring
+diff -ru -x target legacy-app/src/main/resources/application.properties step1/src/main/resources/application.properties
+--- legacy-app/src/main/resources/application.properties
++++ step1/src/main/resources/application.properties
+@@ -3,4 +3,4 @@
+ management.metrics.export.prometheus.enabled=true
+ spring.jpa.hibernate.ddl-auto=create-drop
+ server.max-http-header-size=16KB
+-spring.jpa.properties.javax.persistence.validation.mode=none
++spring.jpa.properties.jakarta.persistence.validation.mode=none
+diff -ru -x target legacy-app/src/test/java/com/ankurm/legacy/CustomerControllerTest.java step1/src/test/java/com/ankurm/legacy/CustomerControllerTest.java
+--- legacy-app/src/test/java/com/ankurm/legacy/CustomerControllerTest.java
++++ step1/src/test/java/com/ankurm/legacy/CustomerControllerTest.java
+@@ -4,15 +4,12 @@
+ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+ 
+-import org.junit.Test;
+-import org.junit.runner.RunWith;
++import org.junit.jupiter.api.Test;
+ import org.springframework.beans.factory.annotation.Autowired;
+ import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+ import org.springframework.boot.test.context.SpringBootTest;
+-import org.springframework.test.context.junit4.SpringRunner;
+ import org.springframework.test.web.servlet.MockMvc;
+ 
+-@RunWith(SpringRunner.class)
+ @SpringBootTest
+ @AutoConfigureMockMvc
+ public class CustomerControllerTest {
+Only in step1/src/main/resources/META-INF: spring

openrewrite/output/03-step1-build.txt

@@ -0,0 +1,3 @@
+# 03-step1-build: after step 1, JDK 17
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
+[INFO] BUILD SUCCESS

openrewrite/output/04-step2-diff.txt

@@ -0,0 +1,65 @@
+# 04-step2-diff: recipe org.openrewrite.java.spring.boot4.UpgradeSpringBoot_4_0 applied on top of step 1 (32 s)
+diff -ru -x target step1/pom.xml step2/pom.xml
+--- step1/pom.xml
++++ step2/pom.xml
+@@ -4,7 +4,7 @@
+   <parent>
+     <groupId>org.springframework.boot</groupId>
+     <artifactId>spring-boot-starter-parent</artifactId>
+-    <version>3.5.16</version>
++    <version>4.0.8</version>
+     <relativePath/>
+   </parent>
+   <groupId>com.ankurm</groupId>
+@@ -18,14 +18,23 @@
+       <groupId>jakarta.servlet</groupId>
+       <artifactId>jakarta.servlet-api</artifactId>
+     </dependency>
+-    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency>
++    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-webmvc</artifactId></dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency>
++    <dependency>
++      <groupId>org.springframework.boot</groupId>
++      <artifactId>spring-boot-starter-restclient</artifactId>
++    </dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-validation</artifactId></dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-security</artifactId></dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency>
+     <dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency>
+     <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
+-    <dependency><groupId>org.springframework.security</groupId><artifactId>spring-security-test</artifactId><scope>test</scope></dependency>
++    <dependency>
++      <groupId>org.springframework.boot</groupId>
++      <artifactId>spring-boot-starter-webmvc-test</artifactId>
++      <scope>test</scope>
++    </dependency>
++    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-security-test</artifactId><scope>test</scope></dependency>
+   </dependencies>
+   <build>
+     <plugins>
+diff -ru -x target step1/src/main/resources/application.properties step2/src/main/resources/application.properties
+--- step1/src/main/resources/application.properties
++++ step2/src/main/resources/application.properties
+@@ -1,6 +1,6 @@
+-spring.redis.host=localhost
+-spring.redis.port=6379
+-management.metrics.export.prometheus.enabled=true
++spring.data.redis.host=localhost
++spring.data.redis.port=6379
++management.prometheus.metrics.export.enabled=true
+ spring.jpa.hibernate.ddl-auto=create-drop
+-server.max-http-header-size=16KB
++server.max-http-request-header-size=16KB
+ spring.jpa.properties.jakarta.persistence.validation.mode=none
+diff -ru -x target step1/src/test/java/com/ankurm/legacy/CustomerControllerTest.java step2/src/test/java/com/ankurm/legacy/CustomerControllerTest.java
+--- step1/src/test/java/com/ankurm/legacy/CustomerControllerTest.java
++++ step2/src/test/java/com/ankurm/legacy/CustomerControllerTest.java
+@@ -6,7 +6,7 @@
+ 
+ import org.junit.jupiter.api.Test;
+ import org.springframework.beans.factory.annotation.Autowired;
+-import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
++import org.springframework.boot.webmvc.test.autoconfigure.AutoConfigureMockMvc;
+ import org.springframework.boot.test.context.SpringBootTest;
+ import org.springframework.test.web.servlet.MockMvc;
+ 

openrewrite/output/05-step2-build.txt

@@ -0,0 +1,3 @@
+# 05-step2-build: after step 2, JDK 17
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
+[INFO] BUILD SUCCESS

openrewrite/output/06-what-it-left-behind.txt

@@ -0,0 +1,13 @@
+# 06-what-it-left-behind (in /tmp/or-work/step2, after both recipes)
+--- leftover 'javax.' string literals or keys in source and resources:
+src/main/java/com/ankurm/legacy/CustomerRepository.java:12:	@QueryHints(@QueryHint(name = "javax.persistence.lock.timeout", value = "3000"))
+--- META-INF files:
+./spring.factories
+./spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports
+--- explicit jakarta.servlet-api dependency added to the pom:
+1
+--- RestTemplate usages (recipe does not touch them):
+src/main/java/com/ankurm/legacy/RemoteClient.java:4:import org.springframework.web.client.RestTemplate;
+src/main/java/com/ankurm/legacy/RemoteClient.java:8:	private final RestTemplate rest = new RestTemplate();
+--- Spring Boot version the recipe stopped at:
+    <version>4.0.8</version>

openrewrite/output/07-step3-boot-4.1.1.txt

@@ -0,0 +1,4 @@
+# 07-step3-boot-4.1.1: parent bumped by hand from the recipe's 4.0.x to 4.1.1, JDK 17
+    <version>4.1.1</version>
+[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
+[INFO] BUILD SUCCESS

openrewrite/output/08-ci-gate.txt

@@ -0,0 +1,4 @@
+# 08-ci-gate (mvn rewrite:dryRun, exit code decides the CI job)
+legacy app,   -Drewrite.failOnDryRunResults=true (the name you would guess): exit code 0
+legacy app,   -DfailOnDryRunResults=true (the real user property):          exit code 1
+migrated app, -DfailOnDryRunResults=true:                                   exit code 0

openrewrite/scripts/rewrite.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# usage: rewrite.sh <from-dir> <to-dir> <recipe-fqn>   (copies from-dir to to-dir and runs the recipe there)
+set -uo pipefail
+RW=6.46.1; SPRING=6.37.1; MIGRATE=3.42.1
+rm -rf "$2"; mkdir -p "$(dirname "$2")"; cp -r "$1" "$2"; rm -rf "$2/target"
+cd "$2"
+mvn -B -q org.openrewrite.maven:rewrite-maven-plugin:$RW:run \
+  -Drewrite.recipeArtifactCoordinates=org.openrewrite.recipe:rewrite-spring:$SPRING,org.openrewrite.recipe:rewrite-migrate-java:$MIGRATE \
+  -Drewrite.activeRecipes="$3" -Drewrite.exportDatatables=false 2>&1

openrewrite/scripts/run-all.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+# Regenerates output/. Needs JDK 17 on JAVA_HOME (the legacy app targets 17), Maven 3.9, network access to Maven Central.
+# Work happens in $WORK (default /tmp/or-work) OUTSIDE this git checkout, because OpenRewrite honours .gitignore
+# and ignores files git ignores (see output/00-gotcha-gitignore.txt).
+set -uo pipefail
+cd "$(dirname "$0")/.."
+WORK=${WORK:-/tmp/or-work}; OUT=$PWD/output; mkdir -p "$OUT"
+R1=org.openrewrite.java.spring.boot3.UpgradeSpringBoot_3_5
+R2=org.openrewrite.java.spring.boot4.UpgradeSpringBoot_4_0
+tests() { (cd "$1" && mvn -B test 2>&1 | grep -E "Tests run:.*Fail|BUILD|ERROR" | grep -v "Time elapsed" | head -${2:-8}); }
+difff() { diff -ru -x target "$1" "$2" | sed -E 's/\t20[0-9-]+ [0-9:.]+ \+0000$//; s#'"$WORK"'/##g'; }
+
+{ echo "# 01-baseline: legacy app, Spring Boot 2.7.18, JDK 17"; tests legacy-app; } > "$OUT/01-baseline.txt"
+
+s=$(date +%s); ./scripts/rewrite.sh legacy-app "$WORK/step1" $R1 >/dev/null 2>&1; e=$(date +%s)
+{ echo "# 02-step1-diff: recipe $R1 on the legacy app ($((e-s)) s)"; difff legacy-app "$WORK/step1"; diff -rq legacy-app "$WORK/step1" -x target | grep '^Only in' | sed "s#$WORK/##"; } > "$OUT/02-step1-diff.txt"
+{ echo "# 03-step1-build: after step 1, JDK 17"; tests "$WORK/step1"; } > "$OUT/03-step1-build.txt"
+
+s=$(date +%s); ./scripts/rewrite.sh "$WORK/step1" "$WORK/step2" $R2 >/dev/null 2>&1; e=$(date +%s)
+{ echo "# 04-step2-diff: recipe $R2 applied on top of step 1 ($((e-s)) s)"; difff "$WORK/step1" "$WORK/step2"; } > "$OUT/04-step2-diff.txt"
+{ echo "# 05-step2-build: after step 2, JDK 17"; tests "$WORK/step2"; } > "$OUT/05-step2-build.txt"
+
+{
+  echo "# 06-what-it-left-behind (in $WORK/step2, after both recipes)"
+  echo "--- leftover 'javax.' string literals or keys in source and resources:"
+  grep -rn 'javax\.' "$WORK/step2/src" | sed "s#$WORK/step2/##" || true
+  echo "--- META-INF files:"; (cd "$WORK/step2/src/main/resources/META-INF" && find . -type f | sort)
+  echo "--- explicit jakarta.servlet-api dependency added to the pom:"; grep -c '<artifactId>jakarta.servlet-api</artifactId>' "$WORK/step2/pom.xml"
+  echo "--- RestTemplate usages (recipe does not touch them):"; grep -rn 'RestTemplate' "$WORK/step2/src" | sed "s#$WORK/step2/##"
+  echo "--- Spring Boot version the recipe stopped at:"; grep -A1 '<artifactId>spring-boot-starter-parent' "$WORK/step2/pom.xml" | grep version
+} > "$OUT/06-what-it-left-behind.txt"
+
+rm -rf "$WORK/step3"; cp -r "$WORK/step2" "$WORK/step3"; rm -rf "$WORK/step3/target"
+sed -i 's#<version>4.0.[0-9]*</version>#<version>4.1.1</version>#' "$WORK/step3/pom.xml"
+{ echo "# 07-step3-boot-4.1.1: parent bumped by hand from the recipe's 4.0.x to 4.1.1, JDK 17"; grep -A1 '<artifactId>spring-boot-starter-parent' "$WORK/step3/pom.xml" | grep version; tests "$WORK/step3"; } > "$OUT/07-step3-boot-4.1.1.txt"
+
+# CI gate: dryRun with failOnDryRunResults. Fails on the legacy app, passes once migrated.
+gate() { (cd "$1" && rm -rf target && mvn -B -q org.openrewrite.maven:rewrite-maven-plugin:6.46.1:dryRun \
+  -Drewrite.recipeArtifactCoordinates=org.openrewrite.recipe:rewrite-spring:6.37.1,org.openrewrite.recipe:rewrite-migrate-java:3.42.1 \
+  -Drewrite.activeRecipes="$2" -D"$3"=true >/dev/null 2>&1; echo "exit code $?"); }
+
+rm -rf "$WORK/g1" "$WORK/g2"; cp -r legacy-app "$WORK/g1"; cp -r "$WORK/step2" "$WORK/g2"
+{ echo "# 08-ci-gate (mvn rewrite:dryRun, exit code decides the CI job)"
+  echo "legacy app,   -Drewrite.failOnDryRunResults=true (the name you would guess): $(gate "$WORK/g1" $R1 rewrite.failOnDryRunResults)"
+  echo "legacy app,   -DfailOnDryRunResults=true (the real user property):          $(gate "$WORK/g1" $R1 failOnDryRunResults)"
+  echo "migrated app, -DfailOnDryRunResults=true:                                   $(gate "$WORK/g2" $R1 failOnDryRunResults)"; } > "$OUT/08-ci-gate.txt"
+
+{ echo "# 00-gotcha-gitignore: same recipe, same project, sources under a .gitignore'd directory"
+  rm -rf "$WORK/ign"; mkdir -p "$WORK/ign"; (cd "$WORK/ign" && git init -q && echo 'legacy/' > .gitignore && cp -r "$OLDPWD/legacy-app" legacy && cd legacy \
+   && mvn -B org.openrewrite.maven:rewrite-maven-plugin:6.46.1:dryRun -Drewrite.recipeArtifactCoordinates=org.openrewrite.recipe:rewrite-spring:6.37.1,org.openrewrite.recipe:rewrite-migrate-java:3.42.1 -Drewrite.activeRecipes=$R1 2>&1 | grep -E "Applying recipes|Parsing|patch file" )
+} > "$OUT/00-gotcha-gitignore.txt"
+ls -1 "$OUT"