Gradle compileOnly and Maven provided

问题

I have a simple project with the retrofit dependency.

dependencies {
    ...
    implementation 'com.squareup.retrofit2:retrofit:2.8.1'
}

If i check the retrofit pom.xml I can find the OkHttp dependency as a compile maven scope that means the old compile gradle configuration as well.

<?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 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>com.squareup.retrofit2</groupId>
    <artifactId>parent</artifactId>
    <version>2.8.1</version>
    <relativePath>../pom.xml</relativePath>
  </parent>

  <artifactId>retrofit</artifactId>
  <name>Retrofit</name>

  <dependencies>
    <dependency>
      <groupId>com.squareup.okhttp3</groupId>
      <artifactId>okhttp</artifactId>
    </dependency>

    <dependency>
      <groupId>com.google.android</groupId>
      <artifactId>android</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.jetbrains.kotlin</groupId>
      <artifactId>kotlin-stdlib</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.jetbrains.kotlinx</groupId>
      <artifactId>kotlinx-coroutines-core</artifactId>
      <optional>true</optional>
    </dependency>

    <dependency>
      <groupId>org.codehaus.mojo</groupId>
      <artifactId>animal-sniffer-annotations</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>com.google.code.findbugs</groupId>
      <artifactId>jsr305</artifactId>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.assertj</groupId>
      <artifactId>assertj-core</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>com.google.guava</groupId>
      <artifactId>guava</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>com.squareup.okhttp3</groupId>
      <artifactId>mockwebserver</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.robolectric</groupId>
      <artifactId>robolectric</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.jetbrains.kotlin</groupId>
        <artifactId>kotlin-maven-plugin</artifactId>
        <executions>
          <execution>
            <id>compile</id>
            <phase>process-sources</phase>
            <goals>
              <goal>compile</goal>
            </goals>
          </execution>
          <execution>
            <id>test-compile</id>
            <phase>test-compile</phase>
            <goals>
              <goal>test-compile</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <configuration>
          <archive>
            <manifestEntries>
              <Automatic-Module-Name>retrofit2</Automatic-Module-Name>
            </manifestEntries>
          </archive>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
        <version>2.10.4</version>
        <configuration>
          <excludePackageNames>retrofit2.internal</excludePackageNames>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

And here comes the part that mess my mind. After check the okhttp pom.xml I don't understand why in Project -> External Libraries I can't find conscrypt, roboelectric, nor mojo except jsr305. Why?

<?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 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>parent</artifactId>
    <version>3.14.7</version>
  </parent>

  <artifactId>okhttp</artifactId>
  <name>OkHttp</name>

  <dependencies>
    <dependency>
      <groupId>com.squareup.okio</groupId>
      <artifactId>okio</artifactId>
    </dependency>
    <dependency>
      <groupId>org.conscrypt</groupId>
      <artifactId>conscrypt-openjdk-uber</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.robolectric</groupId>
      <artifactId>android-all</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>com.google.code.findbugs</groupId>
      <artifactId>jsr305</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.codehaus.mojo</groupId>
      <artifactId>animal-sniffer-annotations</artifactId>
      <version>1.17</version>
      <scope>provided</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>templating-maven-plugin</artifactId>
        <version>1.0.0</version>
        <executions>
          <execution>
            <goals>
              <goal>filter-sources</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
        <version>3.0.1</version>
        <configuration>
          <excludePackageNames>okhttp3.internal:okhttp3.internal.*</excludePackageNames>
          <links>
            <link>http://square.github.io/okio/</link>
          </links>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>3.1.1</version>
        <configuration>
          <archive>
            <manifestEntries>
              <Automatic-Module-Name>okhttp3</Automatic-Module-Name>
            </manifestEntries>
          </archive>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

Question

If maven provide is like gradle compileOnly why I can't access to the code of conscrypt, roboelectric, or mojo?

回答1:

In Maven, provided and test dependencies are not transitively inherited:

If you have a dependency on A, and A has a provided or test dependency on B, then B is not on your classpath.

来源：https://stackoverflow.com/questions/61699706/gradle-compileonly-and-maven-provided