diff --git a/lib/platform/azure/index.js b/lib/platform/azure/index.js
index faf580239ec1ce764da3178c00fb5f0f1294fb4f..d3ea47deba4bc40d0f1a9d00aadd744d9290afc3 100644
--- a/lib/platform/azure/index.js
+++ b/lib/platform/azure/index.js
@@ -153,15 +153,13 @@ function getRepoForceRebase() {
 }
 
 // istanbul ignore next
-async function setBaseBranch(branchName) {
-  if (branchName) {
-    logger.debug(`Setting baseBranch to ${branchName}`);
-    config.baseBranch = branchName;
-    delete config.baseCommitSHA;
-    delete config.fileList;
-    await config.storage.setBaseBranch(branchName);
-    await getFileList(branchName);
-  }
+async function setBaseBranch(branchName = config.baseBranch) {
+  logger.debug(`Setting baseBranch to ${branchName}`);
+  config.baseBranch = branchName;
+  delete config.baseCommitSHA;
+  delete config.fileList;
+  await config.storage.setBaseBranch(branchName);
+  await getFileList(branchName);
 }
 
 // Search
diff --git a/lib/platform/bitbucket/index.js b/lib/platform/bitbucket/index.js
index ce23b84ff00d986f41ed421e89e9333f995359a9..5ddca0466006a226d5c7971b81d8f9c7474591fc 100644
--- a/lib/platform/bitbucket/index.js
+++ b/lib/platform/bitbucket/index.js
@@ -140,15 +140,13 @@ function getRepoForceRebase() {
   return false;
 }
 
-async function setBaseBranch(branchName) {
-  if (branchName) {
-    logger.debug(`Setting baseBranch to ${branchName}`);
-    config.baseBranch = branchName;
-    delete config.baseCommitSHA;
-    delete config.fileList;
-    config.storage.setBaseBranch(branchName);
-    await getFileList(branchName);
-  }
+async function setBaseBranch(branchName = config.baseBranch) {
+  logger.debug(`Setting baseBranch to ${branchName}`);
+  config.baseBranch = branchName;
+  delete config.baseCommitSHA;
+  delete config.fileList;
+  await config.storage.setBaseBranch(branchName);
+  await getFileList(branchName);
 }
 
 // Search
diff --git a/lib/platform/github/index.js b/lib/platform/github/index.js
index dcf61511fd97a0de07fef92492cb982e4421fe65..e8f20ad2780bf5bb2541dd28a3a2586c2e279576 100644
--- a/lib/platform/github/index.js
+++ b/lib/platform/github/index.js
@@ -376,14 +376,12 @@ async function getBranchProtection(branchName) {
   return res.body;
 }
 
-async function setBaseBranch(branchName) {
-  if (branchName) {
-    logger.debug(`Setting baseBranch to ${branchName}`);
-    config.baseBranch = branchName;
-    config.baseCommitSHA = null;
-    config.storage.setBaseBranch(branchName);
-    await getFileList(branchName);
-  }
+async function setBaseBranch(branchName = config.baseBranch) {
+  logger.debug(`Setting baseBranch to ${branchName}`);
+  config.baseBranch = branchName;
+  config.baseCommitSHA = null;
+  await config.storage.setBaseBranch(branchName);
+  await getFileList(branchName);
 }
 
 // Search
diff --git a/lib/platform/gitlab/index.js b/lib/platform/gitlab/index.js
index f08ba719ea1f9dbdae4544b46ea3a15bedfe4b03..842abde7d8e710ae0700a1e3f98b4cf66fc2d887 100644
--- a/lib/platform/gitlab/index.js
+++ b/lib/platform/gitlab/index.js
@@ -164,12 +164,10 @@ function getRepoForceRebase() {
   return false;
 }
 
-async function setBaseBranch(branchName) {
-  if (branchName) {
-    logger.debug(`Setting baseBranch to ${branchName}`);
-    config.baseBranch = branchName;
-    await config.storage.setBaseBranch(branchName);
-  }
+async function setBaseBranch(branchName = config.baseBranch) {
+  logger.debug(`Setting baseBranch to ${branchName}`);
+  config.baseBranch = branchName;
+  await config.storage.setBaseBranch(branchName);
 }
 
 // Search