exit cpplint only after completing all files

hooks/cpplint.py

@@ -19,9 +19,14 @@ def __init__(self, args: List[str]):
 
     def run(self):
         """Run cpplint"""
+        error_occurred = False
         for filename in self.files:
-            self.run_command(self.args + [filename])  # cpplint is unique in requiring args before filename
-            self.exit_on_error()
+            self.run_command_cpplint(self.args + [filename])  # cpplint is unique in requiring args before filename
+            if self.returncode != 0:
+                error_occurred = True
+
+        if error_occurred:
+            sys.exit(1)
 
 
 def main(argv: List[str] = sys.argv):

hooks/utils.py

@@ -143,6 +143,15 @@ def run_command(self, args: List[str]):
         self.stderr += sp_child.stderr
         self.returncode = sp_child.returncode
 
+    def run_command_cpplint(self, args: List[str]):
+        """Run the command and check for errors. Args includes options and filepaths"""
+        args = [self.command, *args]
+        sp_child = sp.run(args, stdout=sp.PIPE, stderr=sp.PIPE)
+        self.returncode = sp_child.returncode
+
+        if self.returncode != 0:
+            sys.stderr.buffer.write(sp_child.stderr + sp_child.stdout)
+
     def exit_on_error(self):
         if self.returncode != 0:
             sys.stderr.buffer.write(self.stdout + self.stderr)