Jenkins workflow job: Use parameter as branch specifier - jenkins

Question

I want to migrate our old free style dev builds, in which we use the branch name as a build parameter, to workflow builds.
This works fine so far, the only thing we are really missing is the ability to use the parameter, e.g. "branch_name", as the branch specifier for the Workflow script from SCM section.
On a free style build this works fine.
Any ideas how this could be achieved? We don't want a dev to change the configuration all the time before starting a build.

Answer 1

Try to disable "Lightweight checkout" checkbox.
This behavior is noted when clicking the help question mark for the "Lightweight checkout" option:
Also build parameters will not be substituted into SCM configuration in this mode.
Found that in latest comments of JENKINS-28447

Answer 2

Sounds like JENKINS-28447:
When selecting the "Groovy CPS DSL from SCM" option for a worflow job,
the SCM plugins do not appear to resolve build parameters or
environment variables. I am using the git plugin and when I use it
from other jobs I can specify a build parameter, like "BuildBranch",
and use that when specifying what branch should be built
The workaround would be to use an inline bootstrap script that calls load after checkout, as described in the tutorial.

Answer 3

Alternately, go further by creating a multibranch workflow project, so that each branch is built automatically with its own history.

Answer 4

I have a workflow DSL script described here: https://groups.google.com/forum/#!msg/jenkinsci-users/jSKwSKbaXq8/dG2mn6iyDQAJ
In that script, I have a build parameter called FREEBSD_SRC_URL , which is
passed down to the workflow. Based on different parameters in that URL,
a different branch can be checked out.
If you are using git, you can still use the same technique for passing a build parameter down to the script, but you would need to do things slightly differently. For example, you could define a parameter BRANCH_NAME in your job and do something like this in your workflow script:
String checkout_url = "https://github.com/jenkinsci/jenkins"
String branch_name = "master"
if (getBinding().hasVariable("CHECKOUT_URL")) {
// override default URL from build parameter
checkout_url = CHECKOUT_URL
}
if (getBinding().hasVariable("BRANCH_NAME")) {
// override default branch from build parameter
branch_name = BRANCH_NAME
}
node {
// Do the git checkout
git branch: "${branch_name}", url: "${checkout_url}"
}