fix: ensure baseBranchSha is set

lib/workers/repository/init/base.ts

@@ -9,6 +9,7 @@ export async function checkBaseBranch(
   logger.debug(`config.repoIsOnboarded=${config.repoIsOnboarded}`);
   let error = [];
   let baseBranchSha: string;
+  // istanbul ignore else
   if (config.baseBranch) {
     // Read content and target PRs here
     if (await platform.branchExists(config.baseBranch)) {
@@ -24,6 +25,8 @@ export async function checkBaseBranch(
       ];
       logger.warn(message);
     }
+  } else {
+    baseBranchSha = await platform.setBaseBranch();
   }
   return { ...config, errors: config.errors.concat(error), baseBranchSha };
 }

lib/workers/repository/init/index.ts

@@ -21,6 +21,7 @@ export async function initRepo(input: RenovateConfig): Promise<RenovateConfig> {
   config.global = config.global || {};
   config = await initApis(config);
   config.semanticCommits = await detectSemanticCommits(config);
+  config.baseBranchSha = await platform.setBaseBranch(config.baseBranch);
   config = await checkOnboardingBranch(config);
   config = await mergeRenovateConfig(config);
   checkIfConfigured(config);