Build Gradle: git branch retuns null

Question

I am trying to fetch the branch the current git head is in as:

String branchName = gitBranchName().toLowerCase()

String gitBranchName() {
    def branch = System.env.GIT_BRANCH
    if (!branch){
        // For local build
        def proc = "git rev-parse --abbrev-ref HEAD".execute()
        proc.in.eachLine { line -> branch = line }
        proc.err.eachLine { line -> println line }
        proc.waitFor()
    }
    return branch
}

on running this it always returns null and hence code breaks when executing gitBranchName().toLowerCase() as toLowerCase() throws error on running for null.

* What went wrong:
Execution failed for task ':init_env'.
> Cannot invoke method toLowerCase() on null object

I guess it is sending the value of branch returned from System.env.GIT_BRANCH which is not set on local machine and it is not waiting for the if block to complete.

Any idea what is wrong and why?

'I guess it is sending the value of branch returned from System.env.GIT_BRANCH which is not set on local machine and it is not waiting for the if block to complete.'- Looks like you answered your own question. — Ashutosh Vaish, Sep 05 '22 at 13:53
@AshutoshVaish yeah may be, but then how do I make it work? I am already using proc.waitFor() — Varun Sukheja, Sep 05 '22 at 14:40
Try restarting your IDE and system after you have set the environment variable. — Ashutosh Vaish, Sep 05 '22 at 15:17
This has almost nothing to do with Git (except that you're running a Git command to produce some output) and almost everything to do with Groovy, which is a downright weird language. See [Groovy executing shell commands](https://stackoverflow.com/q/159148/1256452). — torek, Sep 05 '22 at 15:36

score 0 · Answer 1 · answered Sep 05 '22 at 15:40

I'm using org.ajoberstar.grgit Gradle plugin with success:

plugins {
  id 'org.ajoberstar.grgit' version '5.0.0' apply false
}

import org.ajoberstar.grgit.Grgit

Grgit git = Grgit.open currentDir:project.rootDir
String commit = git.head().abbreviatedId

Build Gradle: git branch retuns null

1 Answers1