Fixing 'Unknown Version' In Frozen Python Apps

Nov 15, 2025 by Alex Johnson 47 views

Fixing 'Unknown Version' in Frozen Python Applications

Hey everyone! 👋 Have you ever packaged your Python application into an executable (.exe) and noticed the version information suddenly displayed as "Unknown"? It's a common issue, and it's because the packaged app no longer has direct access to files like pyproject.toml or setup.py that contain the version details. But don't worry, there are several ways to fix this and get your version information showing up correctly again. Let's dive in and explore the solutions!

The Problem: Why Does the Version Become "Unknown"?

So, what's happening behind the scenes? When you "freeze" your Python application using tools like PyInstaller, cx_Freeze, or PyOxidizer, you're essentially creating a standalone executable. This executable bundles all your code and dependencies into a single file or a directory. The problem is that during this bundling process, the tool doesn't automatically include the version information from your project's configuration file. Because the application can't access pyproject.toml, setup.py, or similar files after being packaged, the version information, which is usually read from these files, defaults to "Unknown". This can be frustrating, especially if you rely on the version number for displaying information or for version-specific logic within your application.

Understanding the Root Cause

The root cause lies in how these freezing tools work. They primarily focus on packaging the code and dependencies to create a portable executable. They don’t inherently know to extract and embed the version information. This information is typically accessed dynamically when the application is running, which is no longer possible after the application is frozen. You might be asking, "Why doesn't the freezing tool just grab the version?" Well, it's a matter of the tools' design and their primary goal of creating executables, not necessarily managing metadata. The tools often provide mechanisms to include metadata, but it's not always done automatically.

The Impact of an "Unknown" Version

The impact of having an "Unknown" version can range from cosmetic to functional. Visually, it can make your application look less professional. Functionally, you might have features in your application that depend on the version number. For example, if you're checking for updates, displaying the version number in the UI, or using the version number for compatibility checks, an unknown version breaks this functionality. Imagine releasing an update and seeing "Unknown" everywhere – not a great look! The lack of version information can also complicate debugging and troubleshooting. When users report issues, you often need the version number to understand which version they're using, making it harder to replicate and fix the problem.

Solution 1: Embedding the Version During the Build Process

The most straightforward approach is to embed the version information directly into your executable during the build process. This ensures that the version is always available, even when the original configuration files are inaccessible. Here’s how you can do it.

Using `setuptools` with `pyproject.toml`

If you use setuptools and pyproject.toml, you can directly access the version during the build. First, make sure your pyproject.toml file contains the version field. For example:

[project]
name = "your_app"
version = "1.2.3"
...other config...

Then, in your Python code, you can use the importlib.metadata module to access this version:

from importlib.metadata import version

# Get the app's name to use when getting the version. 
# This name should match the name in your pyproject.toml file.
app_name = "your_app"

# Try to get the version from the metadata
try:
    version_number = version(app_name)
except Exception:
    version_number = "Unknown"

print(f"Version: {version_number}")

When you freeze your application, the version will be available. You might need to make a small adjustment in your setup.py or the configuration of your freezing tool to ensure that the pyproject.toml file is included in the build process. Most tools will include this by default, but it's a good idea to verify. If you're using PyInstaller, you can add the configuration file directly, or use the --add-data flag.

Using a Custom Version File

Another approach is to create a separate file to hold your version information. This file can be a simple text file, a Python file, or any format you choose. During your build process, you'll update this file with the correct version number.

Creating the Version File:

Create a file, such as version.py, in your project. Inside it, define a variable for the version:

# version.py
__version__ = "1.0.0"

Updating the Version File During Build:

Within your build process (e.g., using a script with setuptools or a build pipeline), you can read the version from your project configuration (e.g., pyproject.toml) and update the version.py file with the correct version number.

Accessing the Version in Your Application:

In your main application code, you can import this version.py file and access the version:

from .version import __version__

print(f"Version: {__version__}")

This method keeps your version information separate from your main code and makes it easy to update during the build process. It also gives you greater control over how the version is stored and accessed.

Custom Build Scripts and Hooks

Many build tools allow you to use custom scripts or hooks during the build process. This provides the most flexibility, allowing you to tailor the process to your specific needs.

Using Build Hooks:

If your freezing tool supports build hooks (like PyInstaller's hook files), you can write a script that runs before the application is packaged. This script can read the version from your configuration files (e.g., pyproject.toml) and inject it into your application.

Example with PyInstaller:

Create a .spec file for PyInstaller. In the .spec file, you can specify additional files and code to be included in the build. For example, you can write a script that updates the version.py file mentioned above. Include the script inside the .spec file by adding the following code:

# In your .spec file
from setuptools.config import read_configuration

config = read_configuration("pyproject.toml")
version = config["metadata"]["version"]

# Create a version file
with open("version.py", "w") as f:
    f.write(f'__version__ = "{version}"')

# Include the version.py file in the build
data = [('version.py', '.')] # Make sure it is in the same directory

exe = EXE(
    # your configuration...
    datas=data, # include our file with version
)

This approach ensures the version is always accessible by the application.

Solution 2: Reading the Version at Runtime

If you want to avoid modifying your build process or if you need more dynamic behavior, you can read the version at runtime. This means your application will try to determine its version every time it starts. It’s useful, particularly if you're frequently changing the version number. However, this method can be less reliable because the application relies on the presence of certain files.

Using the `importlib.metadata` Module

The importlib.metadata module is a powerful tool for reading package metadata. However, this module is most helpful when you have the pyproject.toml or setup.py file bundled in the executable.

Accessing Metadata:

Use importlib.metadata.version() to read the version.

from importlib.metadata import version, PackageNotFoundError

try:
    version_number = version("your_app")
except PackageNotFoundError:
    version_number = "Unknown"

print(f"Version: {version_number}")

Ensure that the name used in version("your_app") matches the name of your package as defined in pyproject.toml. You also might want to include error handling. If the package isn't found, you'll still get "Unknown", but at least the application won't crash.

Parsing Configuration Files at Runtime

Another approach is to parse your configuration files (e.g., pyproject.toml) at runtime. This is less common but can be useful if you need dynamic behavior and are comfortable with the risks of relying on file access. However, this method requires that the configuration file is present in the executable.

Loading the Configuration:

Use a library like toml or configparser to parse the file and extract the version.

import toml

try:
    with open("pyproject.toml", "r") as f:
        config = toml.load(f)
    version_number = config["project"]["version"]
except FileNotFoundError:
    version_number = "Unknown"
except Exception as e:
    version_number = f"Error: {e}"

print(f"Version: {version_number}")

This code tries to open and parse pyproject.toml to get the version. You must be careful to handle potential errors and ensure the file is included when the application is frozen.

Solution 3: Using Environment Variables

Environment variables provide a simple way to pass the version information to the application during runtime. This is particularly useful if you have a deployment pipeline that sets environment variables before the application starts.

Setting the Environment Variable

Before running the executable, set an environment variable with the version number. This can be done in your CI/CD pipeline, deployment scripts, or manually.

# Example in bash
export APP_VERSION="1.2.3"
./your_app.exe

Accessing the Environment Variable in Your Application

Inside your application, use the os.environ module to access the environment variable.

import os

version_number = os.environ.get("APP_VERSION", "Unknown")
print(f"Version: {version_number}")

This approach is simple and doesn't require modifying the build process. The version is passed directly to the application. It is useful for quickly modifying the version information without rebuilding the executable. However, this method makes it harder to track which version of the application is installed on a particular system. It also requires the deployment environment to configure the environment variable.

Choosing the Best Solution

The best solution depends on your specific needs and development workflow. Consider these factors:

Complexity: How much effort are you willing to put into the solution? Embedding the version information during the build process generally requires more setup, but it’s often more reliable.
Reliability: How critical is it that your application always knows its version? Reading from a configuration file at runtime can be less reliable if the file isn't included or accessible.
Maintainability: How easy is it to update the version number? Environment variables are great for dynamic updates, but embedding the version in a build process may be less error-prone.
Deployment Environment: If you use a CI/CD pipeline, environment variables might be the easiest option. If not, embedding the version during the build process may be better. However, the best option is often to embed version information during the build process, as this offers the most control and reliability. It ensures that the version is always available and prevents the "Unknown" issue.

Summary

Dealing with the "Unknown Version" issue when freezing Python applications is a common challenge. By embedding the version during the build process, reading the version at runtime, or using environment variables, you can ensure your application always displays the correct version information. Choose the solution that best fits your project’s needs, and you’ll have a professional-looking application with accurate version information. Happy coding! 🚀

For more in-depth information and best practices, check out these resources:

PyInstaller Documentation: https://pyinstaller.readthedocs.io/

This documentation is a great place to start! 📚