在 leiningen 项目中使用 maven 的“LATEST”关键字

Question

我有两个 leiningen 项目。根据this question，maven 应该允许我使用“最新”作为依赖版本。它给了我一个错误，提示找不到版本“最新”的依赖项。 This answer 表示我如何在本地使用 leiningen 引用这个项目，如果这很重要的话。

如何让它工作？如果这不是您在项目中引用本地依赖项的方式，我愿意接受其他建议。

项目文件如下所示：

(defproject mongo-model "0.0.19-SNAPSHOT"
            :description "A simple way to create model templates for mongodb for write-time data validation"
            :dependencies [[org.clojure/clojure "1.3.0"]]
            :main mongo-model.core)

和

(defproject bayou "0.1.0-SNAPSHOT"
            :description "FIXME: write this!"
            :dependencies [[org.clojure/clojure "1.3.0"]
                           [mongo-model "LATEST"]]
            :main bayou.server)

在第二个项目中运行 lein deps 给我这个错误：

An error has occurred while processing the Maven artifact tasks.
 Diagnosis:

Unable to resolve artifact: Missing:
----------
1) mongo-model:mongo-model:jar:LATEST

  Try downloading the file manually from the project website.

  Then, install it using the command: 
      mvn install:install-file -DgroupId=mongo-model -DartifactId=mongo-model -Dversion=LATEST -Dpackaging=jar -Dfile=/path/to/file

  Alternatively, if you host your own repository you can deploy the file there: 
      mvn deploy:deploy-file -DgroupId=mongo-model -DartifactId=mongo-model -Dversion=LATEST -Dpackaging=jar -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id]

  Path to dependency: 
    1) org.apache.maven:super-pom:jar:2.0
    2) mongo-model:mongo-model:jar:LATEST

----------
1 required artifact is missing.

for artifact: 
  org.apache.maven:super-pom:jar:2.0

from the specified remote repositories:
  clojars (http://clojars.org/repo/),
  central (http://repo1.maven.org/maven2)



Exception in thread "main" Unable to resolve artifact: Missing:
----------
1) mongo-model:mongo-model:jar:LATEST

  Try downloading the file manually from the project website.

  Then, install it using the command: 
      mvn install:install-file -DgroupId=mongo-model -DartifactId=mongo-model -Dversion=LATEST -Dpackaging=jar -Dfile=/path/to/file

  Alternatively, if you host your own repository you can deploy the file there: 
      mvn deploy:deploy-file -DgroupId=mongo-model -DartifactId=mongo-model -Dversion=LATEST -Dpackaging=jar -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id]

  Path to dependency: 
    1) org.apache.maven:super-pom:jar:2.0
    2) mongo-model:mongo-model:jar:LATEST

----------
1 required artifact is missing.

for artifact: 
  org.apache.maven:super-pom:jar:2.0

from the specified remote repositories:
  clojars (http://clojars.org/repo/),
  central (http://repo1.maven.org/maven2)

 (NO_SOURCE_FILE:0)
    at clojure.lang.Compiler.eval(Compiler.java:5440)
    at clojure.lang.Compiler.eval(Compiler.java:5391)
    at clojure.core$eval.invoke(core.clj:2382)
    at clojure.main$eval_opt.invoke(main.clj:235)
    at clojure.main$initialize.invoke(main.clj:254)
    at clojure.main$script_opt.invoke(main.clj:270)
    at clojure.main$main.doInvoke(main.clj:354)
    at clojure.lang.RestFn.invoke(RestFn.java:457)
    at clojure.lang.Var.invoke(Var.java:377)
    at clojure.lang.AFn.applyToHelper(AFn.java:172)
    at clojure.lang.Var.applyTo(Var.java:482)
    at clojure.main.main(main.java:37)
Caused by: Unable to resolve artifact: Missing:
----------
1) mongo-model:mongo-model:jar:LATEST

  Try downloading the file manually from the project website.

  Then, install it using the command: 
      mvn install:install-file -DgroupId=mongo-model -DartifactId=mongo-model -Dversion=LATEST -Dpackaging=jar -Dfile=/path/to/file

  Alternatively, if you host your own repository you can deploy the file there: 
      mvn deploy:deploy-file -DgroupId=mongo-model -DartifactId=mongo-model -Dversion=LATEST -Dpackaging=jar -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id]

  Path to dependency: 
    1) org.apache.maven:super-pom:jar:2.0
    2) mongo-model:mongo-model:jar:LATEST

----------
1 required artifact is missing.

for artifact: 
  org.apache.maven:super-pom:jar:2.0

from the specified remote repositories:
  clojars (http://clojars.org/repo/),
  central (http://repo1.maven.org/maven2)


    at org.apache.maven.artifact.ant.DependenciesTask.doExecute(DependenciesTask.java:175)
    at org.apache.maven.artifact.ant.AbstractArtifactTask.execute(AbstractArtifactTask.java:678)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at clojure.lang.Reflector.invokeMatchingMethod(Reflector.java:90)
    at clojure.lang.Reflector.invokeNoArgInstanceMember(Reflector.java:265)
    at leiningen.deps$do_deps.invoke(deps.clj:131)
    at leiningen.deps$deps.doInvoke(deps.clj:195)
    at clojure.lang.RestFn.invoke(RestFn.java:410)
    at clojure.lang.Var.invoke(Var.java:365)
    at clojure.lang.AFn.applyToHelper(AFn.java:161)
    at clojure.lang.Var.applyTo(Var.java:482)
    at clojure.core$apply.invoke(core.clj:542)
    at leiningen.core$apply_task.invoke(core.clj:228)
    at leiningen.core$_main.doInvoke(core.clj:294)
    at clojure.lang.RestFn.invoke(RestFn.java:410)
    at clojure.lang.AFn.applyToHelper(AFn.java:161)
    at clojure.lang.RestFn.applyTo(RestFn.java:132)
    at clojure.core$apply.invoke(core.clj:542)
    at leiningen.core$_main.invoke(core.clj:297)
    at user$eval42.invoke(NO_SOURCE_FILE:1)
    at clojure.lang.Compiler.eval(Compiler.java:5424)
    ... 11 more
Caused by: org.apache.maven.artifact.resolver.MultipleArtifactsNotFoundException: Missing:
----------
1) mongo-model:mongo-model:jar:LATEST

  Try downloading the file manually from the project website.

  Then, install it using the command: 
      mvn install:install-file -DgroupId=mongo-model -DartifactId=mongo-model -Dversion=LATEST -Dpackaging=jar -Dfile=/path/to/file

  Alternatively, if you host your own repository you can deploy the file there: 
      mvn deploy:deploy-file -DgroupId=mongo-model -DartifactId=mongo-model -Dversion=LATEST -Dpackaging=jar -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id]

  Path to dependency: 
    1) org.apache.maven:super-pom:jar:2.0
    2) mongo-model:mongo-model:jar:LATEST

----------
1 required artifact is missing.

for artifact: 
  org.apache.maven:super-pom:jar:2.0

from the specified remote repositories:
  clojars (http://clojars.org/repo/),
  central (http://repo1.maven.org/maven2)


    at org.apache.maven.artifact.resolver.DefaultArtifactResolver.resolveTransitively(DefaultArtifactResolver.java:324)
    at org.apache.maven.artifact.ant.DependenciesTask.doExecute(DependenciesTask.java:170)
    ... 34 more

Answer 1

这里有两件事在起作用：标准依赖解析和checkouts 目录的便利性。

checkouts 目录

checkouts 目录的功能非常简单：Leiningen 期望在那里找到一个或多个目录，每个目录都包含另一个 Leiningen 项目。通常，您在这里创建指向其他项目的符号链接。对于每个链接的项目，源路径、编译路径和资源路径都添加到类路径中。 （默认情况下 - 可以配置目录列表。）

这意味着链接项目的命名空间在父项目中可用，无论它们是否包含在依赖项中。不过，您仍应将它们包含在依赖项中，以便其他人可以使用您的代码库。

依赖关系

依赖解析机制不关心checkouts 目录。它尝试在本地和远程 Maven 存储库中查找所有依赖项。如果您对从未安装在存储库中的本地项目有依赖关系，则无法找到它，即使项目在checkouts 中链接，Leiningen 也会出现类似问题中所示的错误目录。

您需要在本地存储库中至少安装一次您所依赖的工件。这就像拨打lein install 一样简单。您无需在每次更改后都执行此操作，因为您始终通过 checkouts 符号链接使用最新代码。

关于LATEST 的使用：我会说鼓励对依赖项使用固定版本号。这是防止曾经成功的构建由于依赖关系的变化而突然中断的唯一方法。另请参阅此问题：How do I tell Maven to use the latest version of a dependency?