Maven reactor的构建顺序并不满足所有依赖关系

Question

我在使用Maven的SNAPSHOT构建中的构建顺序有问题。Reactor正在以无效的顺序构建所有罐子。

下面是一个重新创建问题的示例结构（我遇到问题的项目要大得多，

pom.xml        [reactor]
parent/pom.xml [parent]
jar1/pom.xml
jar2/pom.xml
jar3/pom.xml

波姆。xml[Reactor]

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <packaging>pom</packaging>
  <groupId>com.test.buildorder</groupId>
  <artifactId>reactor</artifactId>
  <version>1.0</version>
  <modules>
    <module>jar3</module>
    <module>jar2</module>
    <module>jar1</module>
  </modules>
</project>

家长/家长。xml

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.test.buildorder</groupId>
  <artifactId>parent</artifactId>
  <version>1.1</version>
  <packaging>pom</packaging>

  <dependencyManagement>
  <dependencies>
      <dependency>
        <groupId>com.test.buildorder</groupId>
        <artifactId>jar1</artifactId>
        <version>1.1</version>
      </dependency>
      <dependency>
        <groupId>com.test.buildorder</groupId>
        <artifactId>jar2</artifactId>
        <version>1.0</version>
      </dependency>
      <dependency>
        <groupId>com.test.buildorder</groupId>
        <artifactId>jar3</artifactId>
        <version>1.1</version>
      </dependency>
    </dependencies>
  </dependencyManagement>
</project>

JAR1/pom.xml

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.test.buildorder</groupId>
  <artifactId>jar1</artifactId>
  <version>1.1</version>
  <parent>
    <groupId>com.test.buildorder</groupId>
    <artifactId>parent</artifactId>
    <version>1.1</version>
  </parent>
</project>

JAR2/pom.xml

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.test.buildorder</groupId>
  <artifactId>jar2</artifactId>
  <version>1.1</version>
  <parent>
    <groupId>com.test.buildorder</groupId>
    <artifactId>parent</artifactId>
    <version>1.0</version>
  </parent>

  <dependencies>
    <dependency>
      <groupId>com.test.buildorder</groupId>
      <artifactId>jar1</artifactId>
    </dependency>
  </dependencies>
</project>

JAR3/pom.xml

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.test.buildorder</groupId>
  <artifactId>jar3</artifactId>
  <version>1.1</version>
  <parent>
    <groupId>com.test.buildorder</groupId>
    <artifactId>parent</artifactId>
    <version>1.1</version>
  </parent>

  <dependencies>
    <dependency>
      <groupId>com.test.buildorder</groupId>
      <artifactId>jar2</artifactId>
    </dependency>
  </dependencies>
</project>

我的存储库（在本例中是本地的）只有每个jar的1.0版本，jar3-1.0依赖于jar2-1.0，jar2-1.0依赖于jar1-1.0，每个jar2-1.0都有parent-1.0（如果需要，我可以发布这段代码，但我的问题已经很长了，所以除非有人问我，否则我会推迟）。

我现在安装上面的1.1父pom，然后尝试在反应器上运行安装，并得到以下结果。

[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for com.test.buildorder:jar3:jar:1.1
[WARNING] 'parent.relativePath' points at com.test.buildorder:reactor instead of com.test.buildorder:parent, please verify your project structure @ line 6, column 11
[WARNING]
[WARNING] Some problems were encountered while building the effective model for com.test.buildorder:jar2:jar:1.1
[WARNING] 'parent.relativePath' points at com.test.buildorder:reactor instead of com.test.buildorder:parent, please verify your project structure @ line 6, column 11
[WARNING]
[WARNING] Some problems were encountered while building the effective model for com.test.buildorder:jar1:jar:1.1
[WARNING] 'parent.relativePath' points at com.test.buildorder:reactor instead of com.test.buildorder:parent, please verify your project structure @ line 6, column 11
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] jar3
[INFO] jar2
[INFO] jar1
[INFO] reactor
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building jar3 1.1
[INFO] ------------------------------------------------------------------------
Downloading: https://repo.maven.apache.org/maven2/com/test/buildorder/jar1/1.1/jar1-1.1.jar
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] jar3 ............................................... FAILURE [  0.645 s]
[INFO] jar2 ............................................... SKIPPED
[INFO] jar1 ............................................... SKIPPED
[INFO] reactor ............................................ SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.775 s
[INFO] Finished at: 2015-06-03T16:56:04-05:00
[INFO] Final Memory: 4M/15M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project jar3: Could not resolve dependencies for project com.test.buildorder:jar3:jar:1.1: Could not find artifact com.test.buildorder:jar1:jar:1.1 in central (https://repo.maven.apache.org/maven2) -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException

当我构建1.0版本时，Reactor足够聪明，可以实现依赖树jar3-1.0-

现在，由于jar3-1.1依赖于jar2-1.0（在repo中），反应器并不认为需要首先构建jar1，但调试（使用-X参数）显示依赖关系树为：

[DEBUG] com.test.buildorder:jar3:jar:1.1
[DEBUG]    com.test.buildorder:jar2:jar:1.0:compile
[DEBUG]       com.test.buildorder:jar1:jar:1.1:compile (version managed from 1.0 by com.test.buildorder:parent:1.1)

所以我对这个场景有几个问题：
1。为什么maven认为jar3-1.1对jar1-1.1有一个可传递的依赖关系
2。为什么Reactor没有意识到这种可传递的依赖性，并按照要求的顺序进行构建以满足它
3。我能做些什么来防止这个问题的发生？（最好不重写超过100个POM。）

编辑：找到了第一个问题的答案和第三个问题的一个解决方案。但是仍然想听听第二个问题。

1.因为我从来没有定义依赖项的作用域，maven确定分配了compile的默认作用域。因此，从jar2到jar1的依赖项将显示为依赖于jar2（例如jar3）的jar的传递依赖项。（由com.test.buildorder管理的版本从1.0：父：1.1）通知我依赖项是从jar2-1.0到jar1-1.0，但是因为父为jar 1（1.1）指定了另一个版本，所以需要它。

3.如果我将依赖关系的范围从jar2更改为jar1，并将其更改为provided，则依赖关系不再是可传递的。这假设在运行时所需的JAR都会出现，所以这可能不是每个遇到这个问题的人的解决方案。以下是Maven中可用范围的指南

Answer 1

关于问题2：MavenReactor排序不适用于可传递依赖项，它只计算直接依赖项：

>

jar3-1.1依赖于jar2-1.0（不在反应器中）

jar2-1.1依赖于jar1-1.1

JAR1-1.1

在这种情况下，jar3-1.1和jar1-1.1之间没有链接

预计您不会将反应器中的jar2-1.1与从属管理中的jar2-1.0混合使用

Answer 2

[警告]在为com.test.buildorder构建有效模型时遇到了一些问题： jar3： jar： 1.1[警告]'parent.relative路径'点com.test.buildorder：Reactor而不是com.test.buildorder：父，

因为你的反应器不是父对象，所以我假设你需要明确定义相对路径

<parent>
    <groupId>com.test.buildorder</groupId>
    <artifactId>parent</artifactId>
    <version>1.1</version>
    <relativePath>../parent</relativePath>
  </parent>

此外，您还有不同版本的jar21.0和1.1。对齐它们

Answer 3

我在这里安装了所有项目，所有版本都设置为1.0。然后我改变了你说的版本，得到了同样的错误。

将反应器POM更改为：

 <modules>
    <module>jar1</module>
    <module>jar2</module>
    <module>jar3</module>
</modules>

... 建造成功了。

我看了《使用多个模块、Reactor分拣的指南》，最后一个选项是：

• 在中声明的顺序

读完下一句：

请注意，仅使用“实例化”引用-dependencyManagement和pluginManagement元素不会导致反应器排序顺序的更改

• 我修复了ReactorPOM
• 我对

建造成功了：

[INFO] Reactor Build Order
[INFO]
[INFO] jar3
[INFO] jar1
[INFO] jar2
[INFO] reactor