Kconfiglib

Warnings

• breaking Kconfiglib 2.x is not backwards-compatible with Kconfiglib 1.x. The API changed significantly, replacing functions with properties for accessing symbol values and menu structures. Code written for Kconfiglib 1.x will break.
  Fix: Refer to the Kconfiglib 2.x documentation and `kconfiglib-2-changes.txt` for migration details. Update code to use properties (e.g., `symbol.str_value` instead of `symbol.get_value()`).
• breaking Starting with Kconfiglib 13.0.0, the `windows-curses` package is no longer automatically installed on Windows. This dependency is required for the terminal `menuconfig` interface to function.
  Fix: Manually install `windows-curses` on Windows if you intend to use the terminal `menuconfig`: `pip install windows-curses`.
• deprecated The old syntax for referencing environment variables as `$FOO` is deprecated. The new syntax is `$(FOO)`. While the old syntax is currently supported for compatibility with older Linux kernels, it might be removed in a future major version.
  Fix: Update Kconfig files to use `$(FOO)` for environment variable references.
• gotcha Assignments to hidden (promptless) symbols in configuration files are ignored. These symbols derive their values indirectly from other symbols via `default` or `select`. It's a common mistake to assume such assignments in a `.config` file will be respected when read back by Kconfiglib.
  Fix: Avoid direct assignments to hidden symbols in `.config` files. Configure their controlling symbols instead.
• gotcha Overusing `select` statements in Kconfig can lead to complex and hard-to-debug dependency issues. Changes to a selected symbol's dependencies often require propagating those changes to all symbols that select it, which is easily overlooked.
  Fix: Consider using `depends on` instead of `select` where appropriate to make dependencies explicit and local. Avoid long chains of `select` statements.
• gotcha Kconfiglib may fail to correctly parse `Kconfig.include` files from Linux kernel versions 5.12.1 and newer, leading to `ValueError: invalid literal for int() with base 10: 'error-if'` during parsing.
  Fix: This is an active issue (as of the last check). Check Kconfiglib's GitHub issues for potential patches or workarounds. Ensure your Kconfiglib version is up-to-date, as this might be resolved in newer releases.
• gotcha Within Kconfig files, all hexadecimal literals must be prefixed with `0x` or `0X` to be correctly distinguished from symbol references by the parser.
  Fix: Ensure all hex values in Kconfig files adhere to the `0x...` or `0X...` format.

Install

• pip install kconfiglib Install latest version

Imports

• Kconfig

  from kconfiglib import Kconfig

• Symbol

  from kconfiglib import Symbol

• Kconfiglib 1.x API
  Kconfiglib 2.x (current) replaced functions with properties for accessing symbol values and other object attributes. The Kconfiglib 1.x API is not backwards-compatible.

Quickstart

This quickstart demonstrates how to load a Kconfig file, access symbols, query their properties, and programmatically set their values. It showcases how symbol values are affected by their dependencies.

import os
from kconfiglib import Kconfig

# Create a dummy Kconfig file for demonstration
kconfig_content = """
menu "My Application Configuration"

config MY_FEATURE_ENABLED
    bool "Enable My Feature"
    default y

config MY_STRING_SETTING
    string "My String Setting"
    default "default_value"
    depends on MY_FEATURE_ENABLED

endmenu
"""
with open("Kconfig_example", "w") as f:
    f.write(kconfig_content)

# Load the Kconfig file
kconf = Kconfig("Kconfig_example")

# Access a symbol by its name
feature_symbol = kconf.syms["MY_FEATURE_ENABLED"]
string_symbol = kconf.syms["MY_STRING_SETTING"]

# Print symbol information
print(f"Symbol: {feature_symbol.name}, Prompt: '{feature_symbol.prompt}', Value: {feature_symbol.str_value}")
print(f"Symbol: {string_symbol.name}, Prompt: '{string_symbol.prompt}', Value: {string_symbol.str_value}")

# Set a symbol value
feature_symbol.set_value(0) # Set to 'n'
print(f"Updated {feature_symbol.name} value: {feature_symbol.str_value}")

# Try to set string_symbol, which now depends on MY_FEATURE_ENABLED being 'y'
# This will fail silently or yield an 'n' if the dependency is not met
string_symbol.set_value("new_value")
print(f"Updated {string_symbol.name} value: {string_symbol.str_value} (expected empty if feature disabled)")

# Re-enable MY_FEATURE_ENABLED and set string_symbol
feature_symbol.set_value(2) # Set to 'y'
string_symbol.set_value("new_value_2")
print(f"Updated {string_symbol.name} value: {string_symbol.str_value} (expected 'new_value_2')")

# Clean up the dummy Kconfig file
os.remove("Kconfig_example")