Jenkins: set a parameter defaultValue dynamically - jenkins

Question

I'm trying to set up a multibranch pipeline configuration where the "Deploy" boolean checkbox is defaulted to true on non-production branches, and false on the production build.
pipeline {
parameters{
booleanParam(defaultValue: true, description: 'Do deploy after build', name: 'DEPLOY')
Is there some method to conditionally set defaultValue=false when $BRANCH_NAME == "production"?

Answer 1

I think I might have answered my own question through a bunch of experimentation. This seems crazy simple, but my test between two branches shows the Deploy parameter is properly defaulted on/off depending on the $BRANCH_NAME
def defaultDeploy = true
if ( BRANCH_NAME == "production" )
{
defaultDeploy = false
}
pipeline {
parameters{
booleanParam(defaultValue: defaultDeploy,
description: 'Do deploy after build', name: 'DEPLOY')

Answer 2

Answering the question of the poster in a more generic way, the parameters default values can also be set dynamically injecting properties with EnvInject plugin. Also Extended Choice Parameter plugin is needed to run the example. Create a declarative pipeline project with the following content:
pipeline {
agent any
parameters {
extendedChoice(
name: 'ArchitecturesCh',
defaultValue: "${env.BUILD_ARCHS}",
multiSelectDelimiter: ',',
type: 'PT_CHECKBOX',
value: 'linux-x86_64,android-x86_64,android-arm,android-arm64,ios-arm64,Win32,Win64'
)
string(name: 'ArchitecturesStr', defaultValue: "${env.BUILD_ARCHS}", description: "")
}
stages {
stage('Test') {
steps {
echo params.ArchitecturesCh
echo params.ArchitecturesStr
echo "${env.BUILD_ARCHS}"
}
}
}
}
Then prepare an environment with the EnvInject plugin. NOTE: Be careful not to clash with other environment variables. In my case I lost much time thinking the method was not working because an ARCHITECTURES variable is set somewhere else. In the same pipeline project GUI:
Save and build the pipeline, refresh the page. The default parameters will be available in the following build.

Answer 3

In your question, it's a bit unclear whether BRANCH_NAME refers to an environment variable (as in env.BRANCH_NAME) or to another parameter (as in params.BRANCH_NAME).
If former, then there's some environment variables, meaning that there's an environment, and so a node must have been allocated with its environment set. To allocate a node, the pipeline needs to start running. To start running, the user needs to select the parameters to run the pipeline. So it's a chicken-and-egg problem: you can't have environment variable before running pipelines, and you need to determine the parameters before running the pipeline.
If latter, and you are thinking of a case where, maybe, there's a String parameter that goes by the name of BRANCH_NAME, and a Boolean parameter that goes by the name of DEPLOY, and on the parameters page the checkbox DEPLOY is unchecked when you type maste into BRANCH_NAME, but once you press the r it magically becomes checked ... then it could be done — with a lot of pain — by using the Active Choice plugin.
Finally, if what you want is to prevent any deploying from the master branch, you may check for both the parameter and the branch name before deploying, and refuse to deploy if the parameter is false or if the branch is master.