Ignore git diff errors when there's no origin branch

Signed-off-by: Daniel Widdis <[email protected]>

build.gradle

@@ -228,21 +228,22 @@ task updateVersion {
 ext.createDiffFile = { ->
     def file = Files.createTempFile(URLEncoder.encode(project.name, 'UTF-8'), '.diff').toFile()
     def diffBase = 'refs/remotes/origin/main'
-    // Only run locally
-    if (!System.getenv('CI')) {
-        file.withOutputStream { out ->
-            exec {
-                commandLine 'git', 'diff', '--no-color', '--minimal', diffBase
-                standardOutput = out
-            }
+    file.withOutputStream { out ->
+        exec {
+            ignoreExitValue true
+            commandLine 'git', 'diff', '--no-color', '--minimal', diffBase
+            standardOutput = out
         }
     }
     return file
 }
 
 diffCoverageReport {
     afterEvaluate {
-        diffSource.file = createDiffFile()
+        // For local runs, ignore this on GitHub Actions
+        if (!System.getenv('CI')) {
+            diffSource.file = createDiffFile()
+        }
     }
 
     // View report at build/reports/jacoco/diffCoverage/html/index.html