From 37837afbc88cc14528ea6f9cb197c54689b448dd Mon Sep 17 00:00:00 2001
From: Sebastiaan Huber <mail@sphuber.net>
Date: Wed, 22 Mar 2023 10:14:25 +0100
Subject: [PATCH] Raise `click.BadParameter` if config contains unknown keys

Before, any keys in the configuration file that did not match any
parameters of the command would be silently ignored. This could lead to
confusion with users if they accidentally mistyped a parameter in the
configuration file.

Here, the `configuration_callback` method is updated to cross-reference
the keys in the configuration file with the names of the command's
parameters. If any keys are not recognized a `click.BadParameter` is
raised indicating the unrecognized keys.
---
 click_config_file.py                        | 13 ++++++++++
 tests/test_configuration_option_explicit.py | 28 ++++++++++++++++++---
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/click_config_file.py b/click_config_file.py
index 6236801..aa4287e 100755
--- a/click_config_file.py
+++ b/click_config_file.py
@@ -90,6 +90,19 @@ def configuration_callback(cmd_name, option_name, config_file_name,
         except Exception as e:
             raise click.BadOptionUsage(option_name,
                 "Error reading configuration file: {}".format(e), ctx)
+
+        valid_params = [
+            p.name for p in ctx.command.params if p.name != option_name
+        ]
+        specified_params = list(config.keys())
+        unknown_params = set(specified_params).difference(set(valid_params))
+
+        if unknown_params:
+            raise click.BadParameter(
+                f'Invalid configuration file, the following keys are not '
+                f'supported: {unknown_params}', ctx, param
+            )
+
         ctx.default_map.update(config)
 
     return saved_callback(ctx, param, value) if saved_callback else value
diff --git a/tests/test_configuration_option_explicit.py b/tests/test_configuration_option_explicit.py
index d453d9b..dd7d27f 100644
--- a/tests/test_configuration_option_explicit.py
+++ b/tests/test_configuration_option_explicit.py
@@ -31,13 +31,14 @@ def cli(config):
 
 def test_custom_default_value(runner, cfgfile):
     @click.command()
+    @click.option('--who')
     @configuration_option(implicit=False, default=str(cfgfile), expose_value=True)
-    def cli(config):
+    def cli(who, config):
         assert config == str(cfgfile)
         click.echo(config)
 
     result = runner.invoke(cli)
-    assert not result.exception
+    assert not result.exception, result.output
     assert result.output == ''.join((
         str(cfgfile.realpath()),
         '\n',
@@ -60,9 +61,10 @@ def cli(who):
 def test_config_value_no_replacement(runner, cfgfile):
     """Test that config does not replace variable of other name."""
     @click.command()
+    @click.option('--who')
     @click.option('--whom', default='World', envvar='CLICK_TEST_WHO')
     @configuration_option(implicit=False)
-    def cli(whom):
+    def cli(who, whom):
         assert whom == "World"
         click.echo("Hello {}".format(whom))
 
@@ -73,6 +75,7 @@ def cli(whom):
     assert not result.exception
     assert result.output == 'Hello World\n'
 
+
 def test_broken_config(runner, tmpdir):
     @click.command()
     @configuration_option(implicit=False)
@@ -92,6 +95,25 @@ def cli():
     assert result.exit_code != 0
 
 
+def test_config_unknown_parameters(runner, cfgfile):
+    """Test that the command fails if the configuration file contains unknown parameters."""
+    @click.command()
+    @configuration_option(implicit=False)
+    def cli():
+        pass
+
+    result = runner.invoke(cli, (
+        '--config',
+        str(cfgfile),
+    ))
+    assert re.search(
+        r"Invalid configuration file, the following keys are not supported: {'who'}",
+        result.output
+    ) is not None
+    assert result.exception
+    assert result.exit_code != 0
+
+
 
 def test_config_precedence_override_default(runner, cfgfile):
     @click.command()