Same issue after upgrading to Matrix Project Plugin 1.7, on:

• Jenkins 1.656 (Windows Server 2008 R2, JRE Server 1.8.0_71), and
• Subversion Plugin 2.5.7

IMHO, bumped priority to Critical, because this issue breaks jobs.

Best regards,
Markus

I have the same issue, but with the branch parameters of the Git plugin. This makes it completely impossible to build Gitlab merge requests with Jenkins. It seems the more general problem is inability to pass on parameters from parent build to child builds.

• Jenkins 2.6
• Matrix plugin 1.7
• Git plugin 2.4.4

How many Jenkins-Variable are in use in these cases?
I have a complex test environment.
My jobs have about 70 Variable to describe the different test environments of the slaves and the different test steps to execute for the slaves.
If I try to use Matrix plugin 1.7 I see only 49 of the variables in the matrix jobs after the split.
If I go back to version 1.6 of the matrix project plugin I see all the variables in matrix job after the split

I'm using

• Jenkins 2.10 with define -Dhudson.model.ParametersAction.keepUndefinedParameters=true set

I added two attachments with harcopys of the different varaible listing with the diferent plugin versions

Yesterday I mixed the names of the pdf.

The smaller PDF with 1_6 in the name, a hardcopy of job #593, was done with plugin version 1.7 active.
The larger PDF with 1_7 in the name, a hardcopy of job #594, was done with plugin version 1.6 active.

Beg your pardon for my mistake.

Same issue fully reproducible with SVN in our build environment (started also after upgrading to newer Matrix plugin 1.7.1):
Jeknins 1.656
Matrix Configuration Parameter Plugin 1.0.9
Matrix Groovy Execution Strategy Plugin 1.0.4
Matrix Project Plugin 1.7.1
Matrix Reloaded Plugin 1.1.3
Matrix sorter plugin 1.1
Matrix Tie Parent plugin 1.2