Why do different parts of my build scripts see different values for the project.version property? - gradle

Question

I do the following in gradle in allprojects section...
if (project.hasProperty('myVersion')) {
project.ext.realVersion = project.myVersion
project.version = project.myVersion
println("project version set")
} else {
project.ext.realVersion = 'Developer-Build'
project.version = 'Developer-Build'
println("project version set to devbuild")
}
Now, I have some code that correctly uses project.version and it works, BUT then there is other code that is ALSO using the same property project.versoin and the result is 'unspecified'. If I change both to project.realVersion, they both work. version seems to be this nasty special property that doesn't always seem to work.
The code using the properties is below....(notice where I use realVersion, version does NOT work, but it works fine in the other location :( )....how weird.
task versionFile() << {
File f = new File('output/version');
f.mkdirs()
File v = new File(f, 'version'+project.ext.realVersion)
println('v='+v.getAbsolutePath())
v.createNewFile()
}
task myZip(type: Zip) {
archiveName 'dashboard-'+project.version+'.zip'
from('..') {
include 'webserver/run*.sh'
include 'webserver/app/**'
include 'webserver/conf/**'
include 'webserver/play-1.2.4/**'
include 'webserver/public/**'
include 'webserver/lib/**'
}
from('output/version') {
include '**'
}
}
myZip.dependsOn('versionFile')
assemble.dependsOn('myZip')

Answer 1

The problem has nothing to do with the version property in particular. Build scripts are evaluated sequentially. If you can't guarantee that you are setting the version property before you are reading it, you have to defer reading the property until the end of the configuration phase. Otherwise you'll inevitably run into problems. One way to do this is to put the configuration code that reads the property into a gradle.projectsEvaluated {} block. task.doFirst {} is another way, but has the limitation that the configured value won't be considered for up-to-date checking.
Sometimes there is an easier solution. For example, in the case of archive tasks like Zip, you can just set baseName and extension instead of archiveName. As always, I encourage you to study the DSL reference.

Answer 2

Place the following in doFirst like below:
allprojects {
doFirst {
if (project.hasProperty('myVersion')) {
project.ext.realVersion = project.myVersion
project.version = project.myVersion
println("project version set")
} else {
project.ext.realVersion = 'Developer-Build'
project.version = 'Developer-Build'
println("project version set to devbuild")
}
}
}