S3 Backend Behaves Differently With Multiple Application Names

[dmarmugi]

Describe the bug
Given

• Spring Cloud Config Server Version 4.1.3
• spring.application.name: appA,appB
• spring.profiles.active: dummy

---

When

• Resulting Request: http://<config server>/appA,appB/dummy (the profile name doesn't matter here, just the app names)

---

Then

• Against Git and Vault backends (Multiple spring application name for Vault #1356), this will return appB as propertySources[0] and appA as propertySources[1]
• Against the S3 backend, this will return appA as propertySources[0] and appB as propertySources[1]

---

This is a problem because:
This affects the override behavior in cases where the same value exists in both appA and appB's responses

[dmarmugi]

Searching with regex for \.findOne\("\w+,\w+ turned up these tests:
Vault and Spring Vault have tests asserting precedence:

• spring-cloud-config/spring-cloud-config-server/src/test/java/org/springframework/cloud/config/server/environment/VaultEnvironmentRepositoryTests.java

  Lines 133 to 152 in ae2e244

  	public void findOneWithDefaultKeyAndMultipleApplicationNames() {
  	stubRestTemplate("secret/myapp", toEntityResponse("myapp-foo", "myapp-bar"));
  	stubRestTemplate("secret/yourapp", toEntityResponse("yourapp-foo", "yourapp-bar"));
  	stubRestTemplate("secret/mydefaultkey", toEntityResponse("def-foo", "def-bar"));
  	var properties = new VaultEnvironmentProperties();
  	properties.setDefaultKey("mydefaultkey");
  	var e = vaultEnvironmentRepository(properties).findOne("myapp,yourapp", null, null);
  	assertThat(e.getName()).isEqualTo("myapp,yourapp");
  	assertThat(e.getPropertySources().size()).isEqualTo(3);
  	assertThat(e.getPropertySources().get(0).getSource()).isEqualTo(Map.of("yourapp-foo", "yourapp-bar"));
  	assertThat(e.getPropertySources().get(0).getName()).isEqualTo("vault:yourapp");
  	assertThat(e.getPropertySources().get(1).getSource()).isEqualTo(Map.of("myapp-foo", "myapp-bar"));
  	assertThat(e.getPropertySources().get(1).getName()).isEqualTo("vault:myapp");
  	assertThat(e.getPropertySources().get(2).getSource()).isEqualTo(Map.of("def-foo", "def-bar"));
  	assertThat(e.getPropertySources().get(2).getName()).isEqualTo("vault:mydefaultkey");
  	}

• spring-cloud-config/spring-cloud-config-server/src/test/java/org/springframework/cloud/config/server/environment/vault/SpringVaultEnvironmentRepositoryTests.java

  Lines 142 to 161 in ae2e244

  	public void findOneWithDefaultKeyAndMultipleApplicationNames() {
  	when(keyValueTemplate.get("myapp")).thenReturn(withVaultResponse("myapp-foo", "myapp-bar"));
  	when(keyValueTemplate.get("yourapp")).thenReturn(withVaultResponse("yourapp-foo", "yourapp-bar"));
  	when(keyValueTemplate.get("mydefaultkey")).thenReturn(withVaultResponse("def-foo", "def-bar"));
  	var properties = new VaultEnvironmentProperties();
  	properties.setDefaultKey("mydefaultkey");
  	var e = springVaultEnvironmentRepository(properties).findOne("myapp,yourapp", null, "lbl");
  	assertThat(e.getName()).isEqualTo("myapp,yourapp");
  	assertThat(e.getPropertySources()).hasSize(3);
  	assertThat(e.getPropertySources().get(0).getName()).isEqualTo("vault:yourapp");
  	assertThat(e.getPropertySources().get(0).getSource()).isEqualTo(Map.of("yourapp-foo", "yourapp-bar"));
  	assertThat(e.getPropertySources().get(1).getName()).isEqualTo("vault:myapp");
  	assertThat(e.getPropertySources().get(1).getSource()).isEqualTo(Map.of("myapp-foo", "myapp-bar"));
  	assertThat(e.getPropertySources().get(2).getName()).isEqualTo("vault:mydefaultkey");
  	assertThat(e.getPropertySources().get(2).getSource()).isEqualTo(Map.of("def-foo", "def-bar"));
  	}

So, too, CredHub:

• spring-cloud-config/spring-cloud-config-server/src/test/java/org/springframework/cloud/config/server/environment/CredhubEnvironmentRepositoryTests.java

  Lines 147 to 164 in ae2e244

  	public void shouldRetrieveGivenMultipleApplicationNames() {
  	stubCredentials("/app1/default/myLabel", credential("c1", "k1", "v1"));
  	stubCredentials("/app2/default/myLabel", credential("c2", "k2", "v2"));
  	Environment environment = this.credhubEnvironmentRepository.findOne("app1,app2", null, "myLabel");
  	assertThat(environment.getName()).isEqualTo("app1,app2");
  	assertThat(environment.getProfiles()).containsExactly("default");
  	assertThat(environment.getLabel()).isEqualTo("myLabel");
  	assertThat(environment.getPropertySources()).hasSize(2);
  	assertThat(environment.getPropertySources().get(0).getName()).isEqualTo("credhub-app2-default-myLabel");
  	assertThat(environment.getPropertySources().get(0).getSource()).isEqualTo(Map.of("k2", "v2"));
  	assertThat(environment.getPropertySources().get(1).getName()).isEqualTo("credhub-app1-default-myLabel");
  	assertThat(environment.getPropertySources().get(1).getSource()).isEqualTo(Map.of("k1", "v1"));
  	}

Unfortunately, AWSS3 and Git seem to just assert on size of response:

• spring-cloud-config/spring-cloud-config-server/src/test/java/org/springframework/cloud/config/server/environment/AwsS3EnvironmentRepositoryTests.java

  Lines 259 to 267 in ae2e244

  	public void findWithMultipleApplicationAllFound() throws UnsupportedEncodingException {
  	putFiles("foo-profile1.yml", jsonContent);
  	String versionId = putFiles("bar-profile1.yml", jsonContent);
  	final Environment env = envRepo.findOne("foo,bar", "profile1", null);
  	assertExpectedEnvironment(env, "foo,bar", null, versionId, 2, "profile1");
  	}

• spring-cloud-config/spring-cloud-config-server/src/test/java/org/springframework/cloud/config/server/environment/JGitEnvironmentRepositoryIntegrationTests.java

  Lines 228 to 237 in ae2e244

  	public void nestedWithApplicationPlaceholders() throws IOException {
  	String uri = ConfigServerTestUtils.prepareLocalRepo("nested-repo");
  	this.context = new SpringApplicationBuilder(TestConfiguration.class).web(WebApplicationType.NONE)
  	// TODO: why didn't .properties() work for me?
  	.run("--spring.cloud.config.server.git.uri=" + uri,
  	"--spring.cloud.config.server.git.searchPaths={application}");
  	EnvironmentRepository repository = this.context.getBean(EnvironmentRepository.class);
  	Environment environment = repository.findOne("foo,bar", "staging", "master");
  	assertThat(environment.getPropertySources()).hasSize(3);
  	}