Jenkins Shared Library Recursive Function Calls - jenkins

Question

I have declarative pipeline and uses jenkins shared library. I am trying to make recursive function call within jenkins shared library.
My shared lib structure is something similar to below :
vars/xyz.groovy
Inside xyz.groovy I have method foo, to whom I call xyz.foo from my pipeline which works.
However recursive call from
foo(){
foo() // says No such DSL method
xyz.foo() //says no signature of method: java.lang.class.foo
}
I am trying to understand how to calls functions within jenkins shared library.

Answer 1

this.methodName is rightway to call function recursively inside shared library. All though method is not a part of class. But using this.foo() worked for me.

Answer 2

I was trying something similar to invoke a recursive function with a method declared in the same file .groovy
At the end, the option #Sagar gave didn't work for me
As a workaround, I created the recursive function in a new file (b.groovy) and invoke it from the original file (a.groovy). it worked like a charm :)
example.
b.groovy
/**
* recursive function to compare semantic version form package.json and tag version, only evaluate x.x.x version
* 0 same version
* 1 package.json version is GREATER than repo tag version
* -1 package.json version is SMALLER than repo tag version
*/
int call(ArrayList versionPackageJsonSplit, ArrayList versionTagRepoSplit, Integer iteration) {
if (versionPackageJsonSplit[iteration].toInteger() == versionTagRepoSplit[iteration].toInteger()) {
if (iteration == 2) {
println 'return 0'
return 0
}
return utility_cdkCompareVersions (versionPackageJsonSplit, versionTagRepoSplit, iteration+1) // --> recursive invocation
} else if (versionPackageJsonSplit[iteration].toInteger() > versionTagRepoSplit[iteration].toInteger()) {
println 'return 1'
return 1
} else if (versionPackageJsonSplit[iteration].toInteger() < versionTagRepoSplit[iteration].toInteger()) {
println 'return -1'
return -1
}
}
a.groovy
.
.
.
compareVersionsResult = b (versionPackageJsonSplit, versionTagRepoSplit, 0)
println compareVersionsResult
.
.
.
.
```

Answer 3

So far the least awful way I've found to do this reliably is to create a top-level wrapper method with a recursive closure inside it:
def recursiveMethod(args) {
Closure rec
rec = { arg ->
if (recursiveCase) {
return rec(…)
}
else {
return baseCase
}
}
return rec(…)
}
The upside is that you can reference method args or method-scoped state variables from within the closure without having to pass them around the recursive stack, so recursive calls may look a little cleaner. The downside is a little extra boilerplate to do the wrapping, and also that the closure args have to be named differently than the method args or Groovy raises an error.