From 7b80b0c914e78f75fdceba63886ed446606d2666 Mon Sep 17 00:00:00 2001
From: Shane da Silva <shane@dasilva.io>
Date: Fri, 3 Jan 2020 17:37:30 -0800
Subject: [PATCH] Gracefully handle case where no standard input is provided

Fixes #700.
---
 CHANGELOG.md                                  |  4 ++++
 lib/overcommit/hook_context/pre_push.rb       |  4 ++--
 spec/overcommit/hook_context/pre_push_spec.rb | 10 +++++++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2ed9a5ac..16498f95 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Overcommit Changelog
 
+## master (unreleased)
+
+* Fix case where no standard input is provided to `pre-push` hooks
+
 ## 0.52.0
 
 * Fix `Mdl` to properly parse JSON output from `mdl`
diff --git a/lib/overcommit/hook_context/pre_push.rb b/lib/overcommit/hook_context/pre_push.rb
index 1f37db43..0b2e72a1 100644
--- a/lib/overcommit/hook_context/pre_push.rb
+++ b/lib/overcommit/hook_context/pre_push.rb
@@ -17,8 +17,8 @@ def remote_ref_deletion?
       return @remote_ref_deletion if defined?(@remote_ref_deletion)
 
       @remote_ref_deletion ||= input_lines.
-                               first.
-                               split(' ').
+                               first&.
+                               split(' ')&.
                                first == '(deleted)'
     end
 
diff --git a/spec/overcommit/hook_context/pre_push_spec.rb b/spec/overcommit/hook_context/pre_push_spec.rb
index 8f0a07a2..101e0f1a 100644
--- a/spec/overcommit/hook_context/pre_push_spec.rb
+++ b/spec/overcommit/hook_context/pre_push_spec.rb
@@ -26,8 +26,10 @@
   describe '#remote_ref_deletion?' do
     subject { context.remote_ref_deletion? }
 
+    let(:standard_input) { "#{local_ref} #{local_sha1} #{remote_ref} #{remote_sha1}\n" }
+
     before do
-      input.stub(:read).and_return("#{local_ref} #{local_sha1} #{remote_ref} #{remote_sha1}\n")
+      input.stub(:read).and_return(standard_input)
     end
 
     context 'when pushing new branch to remote ref' do
@@ -56,6 +58,12 @@
 
       it { should == true }
     end
+
+    context 'when no standard input is provided' do
+      let(:standard_input) { '' }
+
+      it { should == false }
+    end
   end
 
   describe '#pushed_refs' do