Provide shell completion for cz

commitizen/cli.py

@@ -3,6 +3,7 @@
 import sys
 from functools import partial
 
+import argcomplete
 from decli import cli
 
 from commitizen import commands, config
@@ -265,6 +266,7 @@ def main():
     conf = config.read_cfg()
     parser = cli(data)
 
+    argcomplete.autocomplete(parser)
     # Show help if no arg provided
     if len(sys.argv) == 1:
         parser.print_help(sys.stderr)

docs/README.md

@@ -144,6 +144,32 @@ commands:
                         current project (default: installed commitizen)
 ```
 
+## Setting up bash completion
+
+When using bash as your shell (limited support for zsh, fish, and tcsh is available), Commitizen can use [argcomplete](https://kislyuk.github.io/argcomplete/) for auto-completion. For this argcomplete needs to be enabled.
+
+argcomplete is installed when you install Commitizen since it's a dependency.
+
+If Commitizen is installed globally, global activation can be executed:
+
+```bash
+sudo activate-global-python-argcomplete
+```
+
+For permanent (but not global) Commitizen activation, use:
+
+```bash
+register-python-argcomplete cz >> ~/.bashrc
+```
+
+For one-time activation of argcomplete for Commitizen only, use:
+
+```bash
+eval "$(register-python-argcomplete cz)"
+```
+
+For further information on activation, please visit the [argcomplete website](https://kislyuk.github.io/argcomplete/).
+
 ## Third-Party Commitizen Templates
 
 See [Third-Party Commitizen Templates](third-party-commitizen.md).

pyproject.toml

@@ -53,6 +53,7 @@ packaging = ">=19,<21"
 tomlkit = "^0.5.3"
 jinja2 = "^2.10.3"
 pyyaml = ">=3.08"
+argcomplete = "^1.12.1"
 
 [tool.poetry.dev-dependencies]
 ipython = "^7.2"

tests/test_cli.py

@@ -1,3 +1,4 @@
+import subprocess
 import sys
 
 import pytest
@@ -78,3 +79,16 @@ def test_commitizen_debug_excepthook(capsys):
     assert excinfo.type == SystemExit
     assert excinfo.value.code == NotAGitProjectError.exit_code
     assert "NotAGitProjectError" in str(excinfo.traceback[0])
+
+
+def test_argcomplete_activation():
+    """
+    This function is testing the one-time activation of argcomplete for
+    commitizen only.
+
+    Equivalent to run:
+    $ eval "$(register-python-argcomplete pytest)"
+    """
+    output = subprocess.run(["register-python-argcomplete", "cz"])
+
+    assert output.returncode == 0