Code is unreachable warning in Python [Solved]

# Code is unreachable warning in Python [Solved]

The Python warning that code is unreachable occurs when you return a value from a function and try to run more code after the function has returned.

To resolve the issue, move your return statement to the bottom of the function and make sure your code is indented properly.

Here is an example of how the warning is caused.

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def example():
    a = 123
    return 'bobbyhadz.com'

    # ⛔️ Code is unreachable Pylance

    # Unreachable code pylint(unreachable)
    b = 456

example()

Notice that the b variable is declared after the function has returned, therefore the line of code is unreachable - it will never run.

In other words, once you return from a function, none of the remaining code in the function runs.

# Correct your indentation

If you meant to declare the variable outside the function, remove the indentation.

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# ✅ works as expected
def example():
    a = 123
    return 'bobbyhadz.com'

b = 456 # 👈️ Declared outside function
print(b)

example()

The variable is now declared outside the function because the indentation is removed, so the warning is no longer raised.

The indented block of code is considered a part of the function.

If you dedent the code, it is a part of the global scope and runs without any issues.

# Move the variable declaration above the return statement

You can also move the block of code or variable declaration above the return statement to resolve the issue.

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def example():
    a = 123
    b = 456 # 👈️ Moved above return statement

    return 'bobbyhadz.com'


example()

The return statement is not followed by any unreachable code, so the issue is resolved.

# Having a condition that always returns True

The warning is also caused if you have a block of code that follows a condition that always runs.

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def example():
    a = 123

    if 10 > 0:
        return 'bobbyhadz.com'

    # ⛔️ Code is unreachable Pylance

    # Unreachable code pylint(unreachable)
    b = 456

example()

The if block is always run because the condition is always met.

The if block returns a value, so the declaration of the b variable is unreachable.

To resolve the issue, make sure you don't have conditions that always return True and are followed by other blocks of code.

# Raising an extension within a function

The warning also occurs if you raise an exception in a function.

Raising an exception stops the execution of the function, so no code after the raise statement runs.

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def example():
    a = 123

    raise ValueError('invalid value')

    # code here is also unreachable



example()

# ⛔️ Code is unreachable Pylance

# Unreachable code pylint(unreachable)
print('This never runs') # 👈️ this line is also unreachable

The raise ValueError line raises an exception and stops the program.

When an exception is raised, the Python interpreter exits, so no additional code is run.

If you need to handle the exception, use a try/except statement.

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def example():
    a = 123

    raise ValueError('invalid value')



try:
    example()
except ValueError:
    # 👇️ This runs
    print('A ValueError occurred...')

We call the function in the try block, it raises an error that is then handled by the except block.

If you don't know the type of exception that might occur, use the generic Exception class.

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def example():
    a = 123

    raise ValueError('invalid value')



try:
    example()
except Exception as e:
    print('A ValueError occurred...', e)

The Exception class is the base class for all non-exit exceptions.

# Resolving the issue in Visual Studio Code

The warning is often caused mistakenly when using Pylance with Visual Studio Code.

If the issue is not in your code, try to solve it by disabling the editor.showUnused setting.

1. Press Ctrl + Shift + P (or Command + Shift + P on macOS).

2. Type user settings json.

3. Click on Preferences: Open User Settings (JSON)

4. Add the following lines of code to your settings.json file.

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"[python]": {
  "editor.showUnused": false
}

You can also add the setting to your .vscode/settings.json file if you only want to apply it to the current project.

1. In the root directory of your project, create a .vscode folder.

2. Create a settings.json file in the .vscode folder.

3. Add the following code to your settings.json file.

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{
  "[python]": {
    "editor.showUnused": false
  }
}

When a setting is set in your .vscode/settings.json file, it only applies to the current project and overrides any global configuration.

# Try to restart your IDE

If you still see the warning, try to restart your code editor.

PyCharm and Visual Studio Code often have issues with reporting stale, non-existent warnings long after they've been fixed.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• Linter pylint is not installed error in VS Code [Solved]
• Consider explicitly re-raising using 'raise Error from'
• How to disable/suppress Tensorflow warnings in Python