support to print --dry-run output

Author: shenxianpeng

cpp_linter_hooks/clang_format.py

@@ -6,27 +6,24 @@
 
 def run_clang_format(args) -> int:
     if expect_version:
-        dry_run_cmd = [f'clang-format-{expect_version}', '-dry-run', '--Werror']
-        edit_cmd = [f'clang-format-{expect_version}', '-i']
+        command = [f'clang-format-{expect_version}', '-i']
     else:
-        dry_run_cmd = ['clang-format', '-dry-run', '--Werror']
-        edit_cmd = ["clang-format", '-i']
+        command = ["clang-format", '-i']
     for arg in args:
         if arg == expect_version or arg.startswith("--version"):
             continue
-        dry_run_cmd.append(arg)
-        edit_cmd.append(arg)
+        command.append(arg)
 
-    retval = 0
     try:
-        sp = subprocess.run(dry_run_cmd, stdout=subprocess.PIPE)
-        retval = sp.returncode
-        output = sp.stdout.decode("utf-8")
-        if retval != 0:
-            subprocess.run(edit_cmd, stdout=subprocess.PIPE)
+        if "--dry-run" in command:
+            sp = subprocess.run(command, stdout=subprocess.PIPE)
+            retval = -1  # Not a fail just identify it's a dry-run.
+            output = sp.stdout.decode("utf-8")
+        retval = subprocess.run(command, stdout=subprocess.PIPE)
         return retval, output
     except FileNotFoundError as e:
-        return 1, e
+        retval = 1
+        return retval, e
 
 
 def main() -> int:

cpp_linter_hooks/clang_tidy.py

@@ -19,7 +19,8 @@ def run_clang_tidy(args) -> int:
         output = sp.stdout.decode("utf-8")
         return retval, output
     except FileNotFoundError as e:
-        return 1, e
+        retval = 1
+        return retval, e
 
 
 def main() -> int: