Is 2.7.0-M1 a valid product version?

[basilevs]

Following error looks suspicious to me. Was minus sign unescaped because it was supposed to be interpreted as a literal at the end of character class expression?

java.lang.IllegalArgumentException: Format "format(n[.n=0;[.n=0;[.S=[A-Za-z0-9_-];='';]]])" was unable to parse 2.7.0-M1
    at org.eclipse.equinox.internal.p2.metadata.VersionFormat.parse (VersionFormat.java:307)
    at org.eclipse.equinox.internal.p2.metadata.VersionParser.parse (VersionParser.java:79)
    at org.eclipse.equinox.p2.metadata.Version.create (Version.java:96)
    at org.eclipse.tycho.p2maven.actions.ProductDependenciesAction.getVersion (ProductDependenciesAction.java:41)
    at org.eclipse.tycho.p2maven.actions.AbstractDependenciesAction.perform (AbstractDependenciesAction.java:79)
    at org.eclipse.equinox.p2.publisher.Publisher$ArtifactProcess.run (Publisher.java:228)
    at org.eclipse.equinox.p2.publisher.Publisher.publish (Publisher.java:258)
    at org.eclipse.tycho.p2.publisher.AbstractMetadataGenerator.publish (AbstractMetadataGenerator.java:121)
    at org.eclipse.tycho.p2.publisher.AbstractMetadataGenerator.generateMetadata (AbstractMetadataGenerator.java:58)
    at org.eclipse.tycho.p2resolver.DefaultDependencyMetadataGenerator.generateMetadata (DefaultDependencyMetadataGenerator.java:39)
    at org.eclipse.tycho.p2resolver.DefaultDependencyMetadataGenerator.generateMetadata (DefaultDependencyMetadataGenerator.java:27)
    at org.eclipse.tycho.p2resolver.P2DependencyResolver.getDependencyMetadata (P2DependencyResolver.java:187)
    at org.eclipse.tycho.p2resolver.P2DependencyResolver.setupProjects (P2DependencyResolver.java:162)
    at org.eclipse.tycho.core.resolver.DefaultTychoResolver.setupProject (DefaultTychoResolver.java:80)
    at org.eclipse.tycho.core.maven.TychoMavenLifecycleParticipant.afterProjectsRead (TychoMavenLifecycleParticipant.java:145)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:223)

Context: eclipse-tycho/tycho#5142 (comment)

[merks]

No that is not a valid OSGi version. The error message shows the syntax. The four parts of an OSGi version are separated by dot. So the - is a syntax error.