Updating invalid pom.xml is skipped silently

[justinedelson]

I ran into a situation today where a module's pom.xml file had a leading space, i.e. the first line was:

 <?xml version="1.0" encoding="UTF-8"?>

Maven's XML parser happily ignored this and built the project. However, when the versions-maven-plugin was used on the aggregator, the module was silently skipped and no debug information indicated the source of the problem (sanitized debug information is below) -- based on the debug information, both the aggregator and its two child modules (core and react-app) should have been updated, but only the aggregator and core was. I had to run a debugger to see the problem.

This is (I hope) a rare occurrence, but I do think it would be useful if something was output in this case.

Debug log:

[INFO] Searching for local aggregator root...
[DEBUG] Checking to see if /Users/jedelson/workspaces/projects/testbed is an aggregator parent
[DEBUG] Local aggregation root is /Users/jedelson/workspaces/projects/testbed/buggy-project
[INFO] Local aggregation root: /Users/jedelson/workspaces/projects/testbed/buggy-project
[DEBUG] Finding child modules...
[DEBUG] Child modules:
[DEBUG]   core
[DEBUG]   react-app
[DEBUG] Removing child modules which are missing...
[DEBUG] After removing missing
[DEBUG]   core
[DEBUG]   react-app
[DEBUG] Finding child modules...
[DEBUG] Child modules:
[DEBUG] None.
[DEBUG] Removing child modules which are missing...
[DEBUG] After removing missing
[DEBUG] None.
[DEBUG] Finding child modules...
[DEBUG] Child modules:
[DEBUG] None.
[DEBUG] Removing child modules which are missing...
[DEBUG] After removing missing
[DEBUG] None.
[INFO] Processing change of *:*:* -> 2018.11.0.test1
[DEBUG] Applying change com.testco:buggy-project: -> 2018.11.0.test1
[DEBUG] Processing root module as parent
[DEBUG] Looking for modules which use com.testco:buggy-project as their parent
[DEBUG] Module:
[DEBUG]     parent is com.testco:buggy-project:
[DEBUG]     will become com.testco:buggy-project:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project:2018.11.0.test1
[DEBUG] Module: core
[DEBUG]     parent is com.testco:buggy-project:0.0.1-SNAPSHOT
[DEBUG]     will become com.testco:buggy-project:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project.core:0.0.1-SNAPSHOT
[DEBUG]     will become com.testco:buggy-project.core:2018.11.0.test1
[DEBUG] Module: react-app
[DEBUG]     parent is com.testco:buggy-project:0.0.1-SNAPSHOT
[DEBUG]     will become com.testco:buggy-project:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project.react:0.0.1-SNAPSHOT
[DEBUG]     will become com.testco:buggy-project.react:2018.11.0.test1
[DEBUG] Processing core as a parent.
[DEBUG] Looking for modules which use com.testco:buggy-project.core as their parent
[DEBUG] Module:
[DEBUG]     parent is com.testco:buggy-project.core:
[DEBUG]     will become com.testco:buggy-project.core:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project:2018.11.0.test1
[DEBUG] Module: core
[DEBUG]     parent is com.testco:buggy-project.core:0.0.1-SNAPSHOT
[DEBUG]     will become com.testco:buggy-project.core:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project.core:2018.11.0.test1
[DEBUG] Module: react-app
[DEBUG]     parent is com.testco:buggy-project.core:0.0.1-SNAPSHOT
[DEBUG]     will become com.testco:buggy-project.core:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project.react:2018.11.0.test1
[DEBUG] Processing react-app as a parent.
[DEBUG] Looking for modules which use com.testco:buggy-project.react as their parent
[DEBUG] Module:
[DEBUG]     parent is com.testco:buggy-project.react:
[DEBUG]     will become com.testco:buggy-project.react:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project:2018.11.0.test1
[DEBUG] Module: core
[DEBUG]     parent is com.testco:buggy-project.react:0.0.1-SNAPSHOT
[DEBUG]     will become com.testco:buggy-project.react:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project.core:2018.11.0.test1
[DEBUG] Module: react-app
[DEBUG]     parent is com.testco:buggy-project.react:0.0.1-SNAPSHOT
[DEBUG]     will become com.testco:buggy-project.react:2018.11.0.test1
[DEBUG]     module is com.testco:buggy-project.react:2018.11.0.test1
[INFO] Processing com.testco:buggy-project
[INFO]     Updating project com.testco:buggy-project
[INFO]         from version  to 2018.11.0.test1
[INFO]
[DEBUG] Skipping generation of backup file
[INFO] Processing com.testco:buggy-project.core
[INFO]     Updating parent com.testco:buggy-project
[INFO]         from version  to 2018.11.0.test1
[INFO]
[DEBUG] Skipping generation of backup file

[fmarot]

+1
I just ran into this weird issue where a colleague had introduced a leading space in the file, and the versions plugin silently ignored this file.
More than a warning in logs, I think the whole build should fail if parsing a pom is impossible.

[stefanseifert]

i'm also of the opinion that a child POM with unparseable XML should not be skipped but fail the build.
PR #399 provides this including an integration tests that validated the failure.