✨ Add typer.set_rich_*() to allow Rich formatting to be disabled

docs/tutorial/printing.md

@@ -140,6 +140,16 @@ In general, **Typer** tends to be the entry point to your program, taking the fi
 
 The best results for your command line application would be achieved combining both **Typer** and **Rich**.
 
+### If you don't want to use Rich formated output
+
+In case you'd rather like to use the simple text ouput, but need **Rich** to be installed in your environment for any other reason, you can disable the use of **Rich** by **Typer**.
+There are two functions in the **Typer** module to control the output format globally, affecting all `typer.Typer()` instances:
+
+ 1. `typer.enable_rich_help`
+ 2. `typer.enable_rich_traceback`
+
+The first one controls all help and **Click's** exception messages. The second one controls the format of the stack trace.
+
 ## "Standard Output" and "Standard Error"
 
 The way printing works underneath is that the **operating system** (Linux, Windows, macOS) treats what we print as if our CLI program was **writing text** to a "**virtual file**" called "**standard output**".

tests/assets/enable_rich.py

@@ -0,0 +1,14 @@
+import typer
+
+typer.enable_rich_help(False)
+
+app = typer.Typer()
+
+
+@app.command()
+def main(arg: str):  # pragma: no cover
+    pass
+
+
+if __name__ == "__main__":
+    app()

tests/assets/enable_rich_traceback_false.py

@@ -0,0 +1,14 @@
+import typer
+
+typer.enable_rich_traceback(False)
+
+app = typer.Typer()
+
+
+@app.command()
+def raise_():
+    raise ValueError  # raise some error to test traceback output
+
+
+if __name__ == "__main__":
+    app()

tests/test_enable_rich.py

@@ -0,0 +1,27 @@
+import subprocess
+import sys
+from pathlib import Path
+
+
+def test_enable_rich_help_is_false():
+    file_path = Path(__file__).parent / "assets/enable_rich.py"
+    result = subprocess.run(
+        [sys.executable, "-m", "coverage", "run", str(file_path), "--help"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf-8",
+    )
+    # assert simple help text
+    assert "─" not in result.stdout
+
+
+def test_enable_rich_traceback_is_false():
+    file_path = Path(__file__).parent / "assets/enable_rich_traceback_false.py"
+    result = subprocess.run(
+        [sys.executable, "-m", "coverage", "run", str(file_path)],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf-8",
+    )
+    # assert simple help text
+    assert "─" not in result.stderr

typer/__init__.py

@@ -28,6 +28,8 @@
 
 from . import colors as colors
 from .main import Typer as Typer
+from .main import enable_rich_help as enable_rich_help
+from .main import enable_rich_traceback as enable_rich_traceback
 from .main import run as run
 from .models import CallbackParam as CallbackParam
 from .models import Context as Context

typer/core.py

@@ -41,13 +41,20 @@
 except ImportError:  # pragma: nocover
     rich = None  # type: ignore
 
+_is_rich_enabled = True
+
 if TYPE_CHECKING:  # pragma: no cover
     if _get_click_major() == 7:
         import click.shell_completion
 
 MarkupMode = Literal["markdown", "rich", None]
 
 
+def set_rich_output(rich_enable: bool) -> None:
+    global _is_rich_enabled
+    _is_rich_enabled = rich_enable
+
+
 # TODO: when deprecating Click 7, remove this
 def _typer_param_shell_complete(
     self: click.core.Parameter, ctx: click.Context, incomplete: str
@@ -232,7 +239,7 @@ def _main(
             if not standalone_mode:
                 raise
             # Typer override
-            if rich:
+            if rich and _is_rich_enabled:
                 rich_utils.rich_format_error(e)
             else:
                 e.show()
@@ -262,7 +269,7 @@ def _main(
         if not standalone_mode:
             raise
         # Typer override
-        if rich:
+        if rich and _is_rich_enabled:
             rich_utils.rich_abort_error()
         else:
             click.echo(_("Aborted!"), file=sys.stderr)
@@ -725,7 +732,7 @@ def main(
         )
 
     def format_help(self, ctx: click.Context, formatter: click.HelpFormatter) -> None:
-        if not rich:
+        if not (rich and _is_rich_enabled):
             return super().format_help(ctx, formatter)
         return rich_utils.rich_format_help(
             obj=self,
@@ -787,7 +794,7 @@ def main(
         )
 
     def format_help(self, ctx: click.Context, formatter: click.HelpFormatter) -> None:
-        if not rich:
+        if not (rich and _is_rich_enabled):
             return super().format_help(ctx, formatter)
         return rich_utils.rich_format_help(
             obj=self,

typer/main.py

@@ -14,7 +14,14 @@
 import click
 
 from .completion import get_completion_inspect_parameters
-from .core import MarkupMode, TyperArgument, TyperCommand, TyperGroup, TyperOption
+from .core import (
+    MarkupMode,
+    TyperArgument,
+    TyperCommand,
+    TyperGroup,
+    TyperOption,
+    set_rich_output,
+)
 from .models import (
     AnyType,
     ArgumentInfo,
@@ -49,6 +56,17 @@
 _original_except_hook = sys.excepthook
 _typer_developer_exception_attr_name = "__typer_developer_exception__"
 
+_is_rich_traceback_enabled = True
+
+
+def enable_rich_help(enable: bool) -> None:
+    set_rich_output(enable)
+
+
+def enable_rich_traceback(enable: bool) -> None:
+    global _is_rich_traceback_enabled
+    _is_rich_traceback_enabled = enable
+
 
 def except_hook(
     exc_type: Type[BaseException], exc_value: BaseException, tb: Optional[TracebackType]
@@ -68,7 +86,7 @@ def except_hook(
     click_path = os.path.dirname(click.__file__)
     supress_internal_dir_names = [typer_path, click_path]
     exc = exc_value
-    if rich:
+    if rich and _is_rich_traceback_enabled:
         rich_tb = Traceback.from_exception(
             type(exc),
             exc,