Gradle Script to Automate Android Versioning by git tags

Question

I got stuck on a Problem with this script. I want to achieve 3 things:

1. fetch the latest tag from git and split the string up into 3 values (Major, Mino, Patch) - Every tag will have that format. Save the fetched data to the properties ext.versionMajor etc.
2. generate a versionCode
3. generate a versionNumber

My goal is to never care about versioning manually my builds. By just keep setting tags via git, this gradle script should automatically update the versionCode and versionNumber.

The Problem When I let gradle compile that script it fails with an Error on Line 77 and the Error just says 0.

 ext.versionMajor = Integer.parseInt(v[0]);

I don´t get it, why does it fail there? Am I assigning the value wrong to the properties?

Im not a gradle pro, I would be really happy if someone has an idea what I am doing wrong.

Link to script 1 link to script 2

Here is the code of the build.gradle file in the app folder of my Adnroid Project.

apply plugin: 'com.android.application'

ext.versionMajor = 0
ext.versionMinor = 0
ext.versionPatch = 0
ext.versionClassifier = null
ext.isSnapshot = true
ext.minimumSdkVersion = 21

//fetch version tag
setVersionNumberByTag()

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.webdesign.crf.eins"
        minSdkVersion minimumSdkVersion
        targetSdkVersion 25
        versionCode generateVersionCode()
        versionName generateVersionName()
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.android.support:design:25.3.1'
    compile 'com.android.support:cardview-v7:25.3.1'
    compile 'com.android.support:support-v4:25.3.1'
    compile 'com.android.volley:volley:1.0.0'
    testCompile 'junit:junit:4.12'
}


private Integer generateVersionCode() {
    return minimumSdkVersion * 10000000 + versionMajor;
}

private String generateVersionName() {
    String versionName = "${versionMajor}.${versionMinor}.${versionPatch}"
    if (ext.versionClassifier == null) {
        if (isSnapshot) {
            versionClassifier = "SNAPSHOT"
        }
    }

    if (ext.versionClassifier != null) {
        versionName += "-" + versionClassifier
    }
    return versionName;
}

private String setVersionNumberByTag() {
    /*
 * Gets the version name from the latest Git tag
 */
    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine 'git', 'describe', '--tags'
        standardOutput = stdout
    }
    String verByGit = stdout.toString().trim()
    String[] v = new String[3];
    v = verByGit.split(".");
    ext.versionMajor = Integer.parseInt(v[0]);
    ext.versionMinor = Integer.parseInt(v[1]);
    ext.versionPatch = Integer.parseInt(v[2]);
}

Answer 1

found a solution

apply plugin: 'com.android.application'

ext.versionMajor = null
ext.versionMinor = 0
ext.versionPatch = 1
ext.versionClassifier = null
ext.isSnapshot = true
ext.minimumSdkVersion = 21


android {
    //fetch version tag
    setVersionNumberByTag()
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.webdesign.crf.eins"
        minSdkVersion minimumSdkVersion
        targetSdkVersion 25
        versionCode generateVersionCode()
        versionName generateVersionName()
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.android.support:design:25.3.1'
    compile 'com.android.support:cardview-v7:25.3.1'
    compile 'com.android.support:support-v4:25.3.1'
    compile 'com.android.volley:volley:1.0.0'
    testCompile 'junit:junit:4.12'
}


private Integer generateVersionCode() {
    return ext.minimumSdkVersion * 10000000 + ext.versionMajor * 10000 + ext.versionMinor * 100 + ext.versionPatch
}

private String generateVersionName() {
    String versionName = "${versionMajor}.${versionMinor}.${versionPatch}"
    if (ext.versionClassifier == null) {
        if (isSnapshot) {
            versionClassifier = "SNAPSHOT"
        }
    }

    if (ext.versionClassifier != null) {
        versionName += "-" + versionClassifier
    }
    return versionName;
}

private String setVersionNumberByTag() {
    /*
 * Gets the version name from the latest Git tag
 */
    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine 'git', 'describe', '--tags'
        standardOutput = stdout
    }
    def String verByGit = stdout.toString().trim()
    def (major, minor, patch) = verByGit.tokenize(".");
    ext.versionMajor = Integer.parseInt(major);
    ext.versionMinor = Integer.parseInt(minor);
    ext.versionPatch = Integer.parseInt(patch);
}

In gradle files groovy is used. That means its not possible to use someString.split("."); like normal in java. I found out, that def (major, minor, patch) = verByGit.tokenize("."); did the trick.