feat(commit): add '--allow-empty' flag to commit command

Signed-off-by: Adrian DC <radian.dc@gmail.com>

Author: Dranaxel

commitizen/cli.py

@@ -162,6 +162,11 @@ def __call__(
                         "default": 0,
                         "help": "length limit of the commit message; 0 for no limit",
                     },
+                    {
+                        "name": "--allow-empty",
+                        "action": "store_true",
+                        "help": "Allow to create a commit without staging changes",
+                    },
                 ],
             },
             {

commitizen/commands/commit.py

@@ -73,14 +73,15 @@ def prompt_commit_questions(self) -> str:
         return message
 
     def __call__(self):
+        allow_empty: bool = self.arguments.get("allow_empty")
         dry_run: bool = self.arguments.get("dry_run")
         write_message_to_file: bool = self.arguments.get("write_message_to_file")
 
         is_all: bool = self.arguments.get("all")
         if is_all:
             c = git.add("-u")
 
-        if git.is_staging_clean() and not dry_run:
+        if git.is_staging_clean() and not (dry_run or allow_empty):
             raise NothingToCommitError("No files added to staging!")
 
         if write_message_to_file is not None and write_message_to_file.is_dir():
@@ -125,6 +126,11 @@ def __call__(self):
                 extra_args += " "
             extra_args += "-s"
 
+        if allow_empty:
+            if extra_args:
+                extra_args += " "
+            extra_args += "--allow-empty"
+
         c = git.commit(m, args=extra_args)
 
         if c.return_code != 0: