What are the steps to reproduce the error?

What does the project structure look like? (Multi-module? inter-dependencies?)

Does a forced build work correctly?

Does a release work if you change the goals to 'clean install' instead of 'clean integration-test'?

It is a big multi-module project with many interdependencies.
Forced build work perfectly
The structure is ear -type (but not all modules are in the ear, there is batches which are not in), and a packaging module (in fact an ANT script)

Steps:

1. Import the parent pom -> OK
2. "clean compile install" all (non-recursive) -> OK (or Build the parent(recursive) OK too, but it is another test )
3. release: "clean install" or "clean integration-test"

TAG: HEAD (I also tried with the tag i want to use for the release...)
3a. update-working-copy -> OK
3b. generate-reactor-projects -> ERROR:

[INFO] Updating local copy against the scm...
[ERROR] org.apache.maven.shared.release.ReleaseExecutionException: Unable to get reactor projects: Failed to build project.
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.execute(GenerateReactorProjectsPhase.java:82)
at org.apache.maven.shared.release.DefaultReleaseManager.prepare(DefaultReleaseManager.java:194)
at org.apache.maven.shared.release.DefaultReleaseManager.prepareWithResult(DefaultReleaseManager.java:107)
at org.apache.maven.continuum.release.executors.PrepareReleaseTaskExecutor.execute(PrepareReleaseTaskExecutor.java:43)
at org.apache.maven.continuum.release.executors.AbstractReleaseTaskExecutor.executeTask(AbstractReleaseTaskExecutor.java:67)
at org.codehaus.plexus.taskqueue.execution.ThreadedTaskQueueExecutor$ExecutorRunnable$1.run(ThreadedTaskQueueExecutor.java:116)
at edu.emory.mathcs.backport.java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:442)
at edu.emory.mathcs.backport.java.util.concurrent.FutureTask.run(FutureTask.java:176)
at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:665)
at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:690)
at java.lang.Thread.run(Thread.java:595)
Caused by: org.apache.maven.continuum.release.ContinuumReleaseException: Failed to build project.
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.addModules(GenerateReactorProjectsPhase.java:169)
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.getReactorProjects(GenerateReactorProjectsPhase.java:109)
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.execute(GenerateReactorProjectsPhase.java:78)
... 10 more
Caused by: org.apache.maven.artifact.resolver.MultipleArtifactsNotFoundException: Missing:
----------
1) commons-net:commons-net:jar:1.2.1

Try downloading the file manually from the project website.

Then, install it using the command:
mvn install:install-file -DgroupId=commons-net -DartifactId=commons-net \
-Dversion=1.2.1 -Dpackaging=jar -Dfile=/path/to/file

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
same message
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

17) ehcache:ehcache:jar:1.3.0

Try downloading the file manually from the project website.

Then, install it using the command:
mvn install:install-file -DgroupId=ehcache -DartifactId=ehcache \
-Dversion=1.3.0 -Dpackaging=jar -Dfile=/path/to/file

Path to dependency:
1) *******:jar:1.0-SNAPSHOT
2) ehcache:ehcache:jar:1.3.0

----------
17 required artifacts are missing.

for artifact:
******-common:jar:1.0-SNAPSHOT

from the specified remote repositories:
central (http://repo1.maven.org/maven2)

at org.apache.maven.artifact.resolver.DefaultArtifactResolver.resolveTransitively(DefaultArtifactResolver.java:305)
at org.apache.maven.artifact.resolver.DefaultArtifactResolver.resolveTransitively(DefaultArtifactResolver.java:272)
at org.apache.maven.artifact.resolver.DefaultArtifactResolver.resolveTransitively(DefaultArtifactResolver.java:253)
at org.apache.maven.project.DefaultMavenProjectBuilder.buildWithDependencies(DefaultMavenProjectBuilder.java:367)
at org.apache.maven.project.DefaultMavenProjectBuilder.buildWithDependencies(DefaultMavenProjectBuilder.java:315)
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.addModules(GenerateReactorProjectsPhase.java:151)
... 12 more

We are seeing the exact same behavior with 1.2.2. Our project structure sounds very similar to gulu's.

Were you using the default local repository in your project group?

I have the same situation as described above. I use continuum 1.2 (Build Number: 697023).
If using goal 'release:prepare', with arguments '-DdryRun=true -DdevelopmentVersion=0.2.0-SNAPSHOT -DreleaseVersion=0.1.0 --batch-mode' it ends success.
When I try do release: "clean install" or "clean integration-test" I have the same error.

I suppose we have same problem, by prepare release using goals: clean install
[INFO] Updating local copy against the scm...
[ERROR] org.apache.maven.shared.release.ReleaseExecutionException: Unable to get reactor projects: Failed to build project.
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.execute(GenerateReactorProjectsPhase.java:82)
at org.apache.maven.shared.release.DefaultReleaseManager.prepare(DefaultReleaseManager.java:194)
at org.apache.maven.shared.release.DefaultReleaseManager.prepareWithResult(DefaultReleaseManager.java:107)
at org.apache.maven.continuum.release.executors.PrepareReleaseTaskExecutor.execute(PrepareReleaseTaskExecutor.java:43)
at org.apache.maven.continuum.release.executors.AbstractReleaseTaskExecutor.executeTask(AbstractReleaseTaskExecutor.java:67)
at org.codehaus.plexus.taskqueue.execution.ThreadedTaskQueueExecutor$ExecutorRunnable$1.run(ThreadedTaskQueueExecutor.java:116)
at edu.emory.mathcs.backport.java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:442)
at edu.emory.mathcs.backport.java.util.concurrent.FutureTask.run(FutureTask.java:178)
at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1061)
at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:575)
at java.lang.Thread.run(Thread.java:619)
Caused by: org.apache.maven.continuum.release.ContinuumReleaseException: Failed to build project.
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.addModules(GenerateReactorProjectsPhase.java:169)
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.getReactorProjects(GenerateReactorProjectsPhase.java:109)
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.execute(GenerateReactorProjectsPhase.java:78)
... 10 more
Caused by: org.apache.maven.artifact.resolver.MultipleArtifactsNotFoundException: Missing:
----------
1) it.bz.prov.egov.common:Common:jar:1.0.5-SNAPSHOT

Try downloading the file manually from the project website.

Then, install it using the command:
mvn install:install-file -DgroupId=it.bz.prov.egov.common -DartifactId=Common -Dversion=1.0.5-SNAPSHOT -Dpackaging=jar -Dfile=/path/to/file

Alternatively, if you host your own repository you can deploy the file there:
mvn deploy:deploy-file -DgroupId=it.bz.prov.egov.common -DartifactId=Common -Dversion=1.0.5-SNAPSHOT -Dpackaging=jar -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id]

Path to dependency:
1) it.bz.prov.egov.common:AnagraficaUnificata:car:1.0.5-SNAPSHOT
2) it.bz.prov.egov.common:Common:jar:1.0.5-SNAPSHOT

----------
1 required artifact is missing.

for artifact:
it.bz.prov.egov.common:AnagraficaUnificata:car:1.0.5-SNAPSHOT

from the specified remote repositories:
egov-default (http://localhost/artifactory/repo/),
central (http://repo1.maven.org/maven2)

at org.apache.maven.artifact.resolver.DefaultArtifactResolver.resolveTransitively(DefaultArtifactResolver.java:324)
at org.apache.maven.artifact.resolver.DefaultArtifactResolver.resolveTransitively(DefaultArtifactResolver.java:288)
at org.apache.maven.artifact.resolver.DefaultArtifactResolver.resolveTransitively(DefaultArtifactResolver.java:269)
at org.apache.maven.project.DefaultMavenProjectBuilder.buildWithDependencies(DefaultMavenProjectBuilder.java:395)
at org.apache.maven.project.DefaultMavenProjectBuilder.buildWithDependencies(DefaultMavenProjectBuilder.java:343)
at org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase.addModules(GenerateReactorProjectsPhase.java:151)
... 12 more

Please, add more informations:

• directory used for local repository
• project group configuration
• POM(s)
  -...

and eventually a small project to reproduce it

Hi,
I had this error as well, on a multi project set up, when trying to relese any child project. I am using continuum standalone. I DL the source and debugged the continuum server, it seems in org.apache.maven.continuum.release.phase.GenerateReactorProjectsPhase:getLocalRepository the arguments string (which correctly contains the local repo location) is split on a " ". So as my repo was in C:\Documents and Settings[me]\.m2\repository the repo was being mangled to:- -Dmaven.repo.local=C:\Documents.

I changed my local repo location in settings.xml to one without a space, re built everything and I can use the release correctly now.

Fixed parsing of local repo with spaces in it in revision 764682.

James Gustards advice works for me on windows with continuum 1.2.3 / svn 1.5.0 / mvn 2.1.0.

The default local maven repository is C:\Documents and Settings\Administrator\.m2\repository

I have tried various things like changing the maven settings.xml files but this did not work.

The following works: I have defined a Local Repository via the GUI (C:\maven\m2\repository).

Next, I edited the my project groups "local repository" to use the new location (via group actions, edit).

I can build, prepare and perform releases with this setup.