探究完，我都想抽自己嘴巴子了~

背景

父级pom.xml：

...
GOF

...

子模块pom.xml:

...
GOF
...

异常

”[ERROR] Child module /data/git/java-demo/GOF of /data/git/java-demo/pom.xml does not exist @ “

[root@devops java-demo]mvn clean install -e -Dmaven.test.skip=true -f pom.xml
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 13, column 21
[ERROR] Child module /data/git/java-demo/GOF of /data/git/java-demo/pom.xml does not exist @ @ 
[ERROR] The build could not read 1 project -> [Help 1]
org.apache.maven.project.ProjectBuildingException: Some problems were encountered while processing the POMs:
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 13, column 21
[ERROR] Child module /data/git/java-demo/GOF of /data/git/java-demo/pom.xml does not exist @ at org.apache.maven.project.DefaultProjectBuilder.build (DefaultProjectBuilder.java:397)at org.apache.maven.graph.DefaultGraphBuilder.collectProjects (DefaultGraphBuilder.java:414)at org.apache.maven.graph.DefaultGraphBuilder.getProjectsForMavenReactor (DefaultGraphBuilder.java:405)at org.apache.maven.graph.DefaultGraphBuilder.build (DefaultGraphBuilder.java:82)at org.apache.maven.DefaultMaven.buildGraph (DefaultMaven.java:507)at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:219)at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke (Method.java:498)at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
[ERROR]   
[ERROR]   The project com.dongle:practice:1.0.0 (/data/git/java-demo/pom.xml) has 1 error
[ERROR]     Child module /data/git/java-demo/GOF of /data/git/java-demo/pom.xml does not exist
[ERROR] 
[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/ProjectBuildingException

说明

• 模块有大写字符Linux下Maven打包就会失败，Windows无异常
• 模块修改成小写字符，打包成功。

探究

跟进异常栈信息：

• org.codehaus.plexus.classworlds.launcher.Launcher.main mvn命令入口
• org.apache.maven.DefaultMaven.execute 执行mvn命令
• org.apache.maven.DefaultMaven.buildGraph 构建项目图谱
• org.apache.maven.graph.DefaultGraphBuilder.getProjectsForMavenReactor 生成maven项目执行/执行器
• org.apache.maven.graph.DefaultGraphBuilder.collectProjects 收集验证项目信息
• org.apache.maven.project.DefaultProjectBuilder.build 生成MavenProject项目信息，每个Module也是一个MavenProject
  在build内部执行逻辑有这样一段逻辑：

        if (recursive) {File basedir = pomFile.getParentFile();List moduleFiles = new ArrayList<>();for (String module : model.getModules()) {if (StringUtils.isEmpty(module)) {continue;}module = module.replace('\\', File.separatorChar).replace('/', File.separatorChar);File moduleFile = new File(basedir, module);if (moduleFile.isDirectory()) {moduleFile = modelProcessor.locatePom(moduleFile);}if (!moduleFile.isFile()) {ModelProblem problem = new DefaultModelProblem("Child module " + moduleFile + " of " + pomFile + " does not exist",ModelProblem.Severity.ERROR,ModelProblem.Version.BASE,model,-1,-1,null);result.getProblems().add(problem);noErrors = false;continue;}if (Os.isFamily(Os.FAMILY_WINDOWS)) {// we don't canonicalize on unix to avoid interfering with symlinkstry {moduleFile = moduleFile.getCanonicalFile();} catch (IOException e) {moduleFile = moduleFile.getAbsoluteFile();}} else {moduleFile = new File(moduleFile.toURI().normalize());}if (aggregatorFiles.contains(moduleFile)) {StringBuilder buffer = new StringBuilder(256);for (File aggregatorFile : aggregatorFiles) {buffer.append(aggregatorFile).append(" -> ");}buffer.append(moduleFile);ModelProblem problem = new DefaultModelProblem("Child module " + moduleFile + " of " + pomFile + " forms aggregation cycle " + buffer,ModelProblem.Severity.ERROR,ModelProblem.Version.BASE,model,-1,-1,null);result.getProblems().add(problem);noErrors = false;continue;}moduleFiles.add(moduleFile);}

好吧，找到这里我好像知道哪里问题了，真是干脆！
忘了windows文件系统不区分大小写了，linux文件系统命名时区分大小写的！！！

定位

项目的GOF模块的目录名是gof！Linux区分到消息，导致module找不到对应的module目录。这时间浪费的，毫无意义，奇葩行为！

解决

• 保险方案：模块名和目录名一致，建议还是都小写吧，不要奇葩行为了！