[jira] [Comment Edited] (MNG-7033) Excluded projects through -pl should not need to be in the reactor

["Marcel Stör (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MNG-7033?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17418111#comment-17418111 ] 

Marcel Stör edited comment on MNG-7033 at 9/21/21, 8:16 PM:
------------------------------------------------------------

Just hit this and thought "Gee, Maven...if I explicitly tell you NOT to build module-X you shouldn't complain if module-X isn't there".

I see that, although not explicitly mentioned, with https://github.com/apache/maven/pull/446/files#diff-47ee27138d1f3dc574d6b9bdb7e15ea07a541336a8bfda4aa050af4272cbf118R135 (stemming from MNG-6511) I can _exclude optional modules_ which is sort of brain twister: {{!?test4}} -> ignore it if it's there, I guess.

Q1: can this be closed now?
Q2: [~agentgt], [~martinkanters] in your opinion, what is an acceptable workaround for Maven 3.6+ to have Maven not fail on missing excluded modules? I can't resort to profiles.

I am currently using something hellishly ugly like this that is maintainable because there are only two modules/folders we need to check against.

{code}
MVN_CMD="mvn ..."

if [ -d "module-x" ] && [ -d "module-y" ]; then
    MVN_CMD="$MVN_CMD -pl !module-x,!module-y"
elif [ -d "module-x" ]; then
    MVN_CMD="$MVN_CMD -pl !module-x"
elif [ -d "module-y" ]; then
    MVN_CMD="$MVN_CMD -pl !module-y"
fi

echo "$MVN_CMD"
...
{code}


was (Author: marcelstoer):
Just hit this and thought "Gee, Maven...if I explicitly tell you NOT to build module-X you shouldn't complain if module-X isn't there".

I see that, although not explicitly mentioned, with https://github.com/apache/maven/pull/446/files#diff-47ee27138d1f3dc574d6b9bdb7e15ea07a541336a8bfda4aa050af4272cbf118R135 (stemming from MNG-6511) I can _exclude optional modules_ which is sort of brain twister: {{!?test4}} -> ignore it if it's there, I guess.

Q1: can this be closed now?
Q2: [~agentgt], [~martinkanters] in your opinion, what is an acceptable workaround for Maven 3.6+ to have Maven not fail on missing excluded modules? I can't resort to profiles.

> Excluded projects through -pl should not need to be in the reactor
> ------------------------------------------------------------------
>
>                 Key: MNG-7033
>                 URL: https://issues.apache.org/jira/browse/MNG-7033
>             Project: Maven
>          Issue Type: Improvement
>          Components: Command Line
>    Affects Versions: 3.6.0, 3.6.1, 3.6.3
>            Reporter: Adam Gent
>            Priority: Major
>
> TLDR if you exclude a module using {{!module}} or {{-module}} with {{-pl}} that module needs to somehow be in the resolved reactor.
> We have custom build scripts (e.g. shells scripts or makes) that will make a certain subset of the project using {{-pl}}. However some modules we want to always exclude. (Yes we could use profiles but the maintenance of that solution is unacceptable to us).
> Thus if we do something like this:
> {code:sh}
> mvn install -pl "snaphop-cache,-snaphop-http" -amd
> {code}
> We may or not may not get the following depending on whether snaphop-cache has a downstream dependency on snaphop-http:
> {code}
> [INFO] Scanning for projects...
> [ERROR] [ERROR] Could not find the selected project in the reactor: snaphop-http @
> [ERROR] Could not find the selected project in the reactor: snaphop-http -> [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/MavenExecutionException
> {code}
> Thus it becomes nontrivial to exclude a module. One has to know whether or not {{snaphop-cache}} will trigger {{snaphop-http}} to be in the reactor.
> Furthermore the command may fail if some one changes dependencies (not project structure or modules). 
> I find that to be alarming. {{-pl}} shouldn't fail if dependencies change. 
> Its notable that the following is completely fine:
> {code:sh}
> mvn install -pl "snaphop-cache,snaphop-http" -amd
> {code}
> Which is confusing and inconsistent that one can't then add {{-}}.
> My recommendation is if -pl can't find the exclusion module in the currently selected reactor is just ignores it or perhaps issues a warning.



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