Quite honestly this is a horrendous abuse of configuration, not to mention
design and security principles, and thoroughly inelegant.
It brings to mind a Go proverb "A little copying is better than a little
dependency."
I've had my say though. If you want to set a property and not have it
inherited in other repos, put it in .\.mvn\maven.config
Delany
On Thu, 3 Aug 2023 at 03:45, Garret Wilson <gar...@globalmentor.com> wrote:
> On 8/1/2023 7:42 PM, Garret Wilson wrote:
> > …
> > Now the child POMs can turn off deployment by simply setting
> > `maven.deploy.skip` to `false`, and kill two birds with one stone:
> > deployment will be disabled whether the Nexus Staging Plugin or the
> > Maven Deploy Plugin was used.
>
> In my previous message I explained how to set up the Nexus Staging
> Plugin so that it can easily be disabled in child projects (along with
> the Maven Build Plugin) using one simple property: `maven.deploy.skip`.
> Now for the next step, the grand finale.
>
> In my original question, I asked if there was a way to keep the Nexus
> Staging Plugin from being inherited in child POMs by default. Really
> "inherited" is an implementation detail. What I really wanted to know is
> if there was to configure the Nexus Staging Plugin to be enabled by
> default in the parent POM, but be disabled by default in the child POM.
> The semantic distinction is subtle, but important; it turns out that
> there's no way to turn off inheritance, but with a few tricks (i.e.
> quite a few very ugly hacks), we can change the default configuration
> based upon whether the plugin is being invoked in the parent POM (here
> `com.globalmentor:globalmentor-root`) or from some child POM.
>
> If Maven supported expressions (oh, if only), this would be rather
> straightforward. Since it doesn't we'll use
> `org.codehaus.mojo:build-helper-maven-plugin` to do things that no one
> should ever have to do (or even consider) in a POM; it looks like this:
>
> ```xml
> <plugin>
> <groupId>org.codehaus.mojo</groupId>
> <artifactId>build-helper-maven-plugin</artifactId>
> <executions>
> <execution>
> <id>set-is-skip-deploy-false-or-prefixed</id>
> <phase>validate</phase>
> <goals>
> <goal>regex-property</goal>
> </goals>
> <configuration>
> <name>maven.deploy.skip</name>
> <value>_${project.groupId}_${project.artifactId}</value>
> <regex>^_com\.globalmentor_globalmentor-root$</regex>
> <replacement>false</replacement>
> <failIfNoMatch>false</failIfNoMatch>
> </configuration>
> </execution>
> <execution>
> <id>set-is-skip-deploy</id>
> <phase>initialize</phase>
> <goals>
> <goal>regex-property</goal>
> </goals>
> <configuration>
> <name>maven.deploy.skip</name>
> <value>${maven.deploy.skip}</value>
> <regex>^_.*</regex>
> <replacement>true</replacement>
> <failIfNoMatch>false</failIfNoMatch>
> </configuration>
> </execution>
> </executions>
> </plugin>
> ```
>
> I won't explain here what's going on; I intend to write a blog post
> about it some day. The end result is that if the
> `com.globalmentor:globalmentor-root` POM is in effect, the
> `maven.deploy.skip` property is set to `true`; for any other descendant
> project, the `maven.deploy.skip` property is set to `false`. It works
> like this pseudocode:
>
> ```xml
> <properties>
>
> <maven.deploy.skip>$("${project.groupId}:${project.artifactId}}"!="com.globalmentor:globalmentor-root)</maven.deploy.skip>
> ```
>
> (Wouldn't it be nice to have expressions like this.)
>
> I succeeded in pulling off effectively what I asked for. But in reality
> I would like the `maven.deploy.skip` property to be determined by
> whether `nexus.host` is set to some value, and I want `nexus.host` to be
> set to a default value in `com.globalmentor:globalmentor-root` but not
> in child POMs. But that sort of two-layered logic (although simple if
> Maven supported expressions) is too much for the ugly kludge I'm using
> (and more than my mind wants to deal with).
>
> So in the end I settled for a sort of compromise: I made the value of
> `maven.deploy.skip` dependent on whether `nexus.host` is set to a
> non-empty string. Thus the Nexus Staging Plugin is enabled by default,
> but in any child POM I can easily turn off deployment by setting the
> `nexus.host` to the empty string, like this:
>
> ```xml
> <properties>
> <nexus.host></nexus.host>
> ```
>
> This automatically turns off `maven.deploy.skip` via this ugly kludge:
>
> ```xml
> <plugin>
> <groupId>org.codehaus.mojo</groupId>
> <artifactId>build-helper-maven-plugin</artifactId>
> <executions>
> <execution>
> <id>set-is-skip-deploy-true-or-prefixed</id>
> <phase>validate</phase>
> <goals>
> <goal>regex-property</goal>
> </goals>
> <configuration>
> <name>maven.deploy.skip</name>
> <value>_${nexus.host}</value>
> <regex>^_$</regex>
> <replacement>true</replacement>
> <failIfNoMatch>false</failIfNoMatch>
> </configuration>
> </execution>
> <execution>
> <id>set-is-skip-deploy</id>
> <phase>initialize</phase>
> <goals>
> <goal>regex-property</goal>
> </goals>
> <configuration>
> <name>maven.deploy.skip</name>
> <value>${maven.deploy.skip}</value>
> <regex>^_.*</regex>
> <replacement>false</replacement>
> <failIfNoMatch>false</failIfNoMatch>
> </configuration>
> </execution>
> </executions>
> </plugin>
> ```
>
> I'll live with this for now. I'll probably wind up writing a Maven
> set-property-from-expression plugin at some point, when I can't digest
> this sort of nasty workaround any more.
>
> Garret
>
>
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