Mypy Does Not Return Non-Zero Exit Code for Invalid mypy.ini Values Followed by Comments, including 'strict'

Bug Report

Description

When using a comment in an mypy.ini file, it interferes with the parsing of boolean values, leading to unintended behavior. Specifically, if a boolean value is followed by a comment, mypy does not return a non-zero exit code, even if the value is invalid. This can lead to unexpected configuration changes and, in the example provided, turns off the 'strict' mode.

To Reproduce

[mypy]
strict = true # this comment turns strict off

Expected Behavior

Mypy should return a non-zero exit code when encountering invalid configuration values, even if they are followed by a comment.

Actual Behavior

Mypy outputs a warning but does not return a non-zero exit code, allowing the invalid configuration to take effect.

mypy.ini: [mypy]: strict: Not a boolean: true # this comment turns strict off

Your Environment

• Mypy version used: 1.7.0, 1.8.0
• Mypy command-line flags: ''
• Mypy configuration options from mypy.ini (and other config files): n/a
• Python version used: Python 3.10.11

Start by reproducing the behavior with the provided mypy.ini configuration and trace mypy's configuration parsing and validation entry point. Add coverage for a boolean value followed by a comment, and verify that invalid values produce a non-zero exit code while valid values remain unchanged.