Optional keystore properties

app/build.gradle

@@ -9,6 +9,7 @@ def getReleaseName = { -> return "Vallibonavenatrix" }
 // https://en.wikipedia.org/wiki/List_of_dinosaur_genera
 
 def keystoreProperties = new Properties()
+if (rootProject.file("keystore.properties").exists())
     keystoreProperties.load(new FileInputStream(rootProject.file("keystore.properties")))
 
 Properties localProperties = new Properties()
@@ -135,9 +136,10 @@ android {
         }
     }
 
-    // https://google.github.io/android-gradle-dsl/current/com.android.build.gradle.internal.dsl.SigningConfig.html
+    // https://developer.android.com/reference/tools/gradle-api/4.2/com/android/build/api/dsl/SigningConfig
     signingConfigs {
         release {
+            if (rootProject.file("keystore.properties").exists()) {
                 storeFile file(keystoreProperties['storeFile'])
                 storePassword keystoreProperties['storePassword']
                 keyAlias keystoreProperties['keyAlias']
@@ -146,6 +148,7 @@ android {
                 v2SigningEnabled true
             }
         }
+    }
 
     buildFeatures {
         buildConfig = true