diff --git a/arrow.gd b/arrow.gd
index 0415efe..c38ac30 100644
--- a/arrow.gd
+++ b/arrow.gd
@@ -7,7 +7,7 @@ var repository: Container
 func _ready():
 	pass
 
-func _process(delta):
+func _process(_delta):
 	if repository and repository.objects.has(target):
 		var t = repository.objects[target]
 		#print(t)
diff --git a/main.gd b/main.gd
index a508f7d..c1695fb 100644
--- a/main.gd
+++ b/main.gd
@@ -87,11 +87,11 @@ func construct_repo(script, path):
 	shell.run("mkdir " + path)
 	shell.cd(path)
 	shell.run("git init")
-	var output = shell.run("source "+script_path)
+	var o = shell.run("source "+script_path)
 	if game.debug:
-		print(output)
+		print(o)
 	
-func _process(delta):
+func _process(_delta):
 	if server.is_connection_available():
 		client_connection = server.take_connection()
 		read_commit_message()
diff --git a/node.gd b/node.gd
index c93715f..766ab8a 100644
--- a/node.gd
+++ b/node.gd
@@ -14,7 +14,7 @@ var arrow = preload("res://arrow.tscn")
 func _ready():
 	pass
 
-func _process(delta):
+func _process(_delta):
 	if held:
 		global_position = get_global_mouse_position()
 		
@@ -83,7 +83,7 @@ func _on_unhover():
 		$Content.visible = false
 		$ID.visible = false
   
-func _input_event(viewport, event, shape_idx):
+func _input_event(_viewport, event, _shape_idx):
 	if event is InputEventMouseButton:
 		if event.button_index == BUTTON_LEFT:
 			held = event.pressed
diff --git a/repository.gd b/repository.gd
index cd53c9f..5da5de7 100644
--- a/repository.gd
+++ b/repository.gd
@@ -11,7 +11,7 @@ var objects = {}
 func _ready():
 	pass
 
-func _process(delta):
+func _process(_delta):
 	if path:
 		apply_forces()
 		
@@ -184,9 +184,10 @@ func commit_parents(id):
 
 func all_refs():
 	var refs = []
-	for line in git("show-ref", true):
+	# If there are no refs, show-ref will have exit code 1. We don't care.
+	for line in git("show-ref || true", true):
 		line = line.split(" ")
-		var id = line[0]
+		var _id = line[0]
 		var name = line[1]
 		refs.push_back(name)
 	return refs
diff --git a/shell.gd b/shell.gd
index 9e67ea3..564370f 100644
--- a/shell.gd
+++ b/shell.gd
@@ -46,9 +46,12 @@ func _exec(command, args=[]):
 		print("exec: %s [%s]" % [command, PoolStringArray(args).join(", ")])
 		
 	var output = []
-	OS.execute(command, args, true, output, true)
+	var exit_code = OS.execute(command, args, true, output, true)
 	output = output[0]
 	
+	if exit_code != 0:
+		push_error("OS.execute failed: %s [%s] Output: %s" % [command, PoolStringArray(args).join(", "), output])
+	
 	if debug:
 		print(output)