Upcoming changes

These changes are now available to our beta testers!

Sourcery 0.9.3

New option to permanently turn off a type of refactoring for a user

When a refactoring only uses one proposal, there will now be a menu option in VS Code and PyCharm to ;Never show me this refactoring', or 'Turn off this refactoring permanently'. This will permanently disable this proposal, and it will not be displayed to the user again on that machine. This configuration is stored in a .sourcery.yaml file in the user's config location (.config/sourcery) on linux. Other configuration can also be set up in this file, for example to configure the clone detection parameters.

When this option is taken a notification is displayed to the user asking for feedback and giving them the location of this config file if they wish to edit it and undo the action.

As part of these changes the 'skip all' menu option has been removed, to avoid having too many Sourcery options. Adding # sourcery: skip to a function definition will still work as before.

Note - in PyCharm this feature will not function until we do a new release of the PyCharm plugin - coming soon.

New refactorings

Merge Except Handler

Sourcery refactoring id: merge-except-handler

Description:

Merge except handlers with identical code blocks

Before:

try:
    connect(credentials)
except ConnectionError as e:
    log_error(e)
except RuntimeError as e:
    log_error(e)

After:

try:
    connect(credentials)
except (ConnectionError, RuntimeError) as e:
    log_error(e)

Explanation:

Reduce repetition across equivalent exception handlers by combining them into one with a tuple.

Extends the min-max-identity refactoring to the following case:

c = a if a < b else b

c = min(a, b)

Bug fixes

• No longer suggest comprehensions containing an await or yield
• Scan for refactoring and detect clones will now work correctly in VS Code on Windows
• Fix issue where Sourcery could incorrectly suggest removal of a variable used in a pandas query

Sourcery 0.9.2

Class level extract method (VS Code only)

Sourcery can now perform class-level refactorings. The first one is extracting duplicate code into methods at the class level.

Normally Sourcery scans for refactorings on every code change. Class-level ones need to do more analysis, so this will only run on file open and save.

Class-level extract method

Sourcery refactoring id: class-extract-method

Description:

Extract duplicate code from different methods into a new one

Requires Sourcery Pro

Before:

class TestClass:
  def extraction_example(self):
    self.speed_slider = Scale(
      self.master, from_=1, to=10, orient=HORIZONTAL, label='Speed')
    self.speed_slider.pack()
    self.speed_slider.set(DEFAULT_SPEED)
    self.speed_slider.configure(background='white')

  def intervening_function(self):
    if True:
      pass

  def next_example(self):
    self.force_slider = Scale(
      self.master, from_=1, to=10, orient=HORIZONTAL, label='Force')
    self.force_slider.pack()
    self.force_slider.set(DEFAULT_FORCE)
    self.force_slider.configure(background='white')

After:

class TestClass:
  def extraction_example(self):
    self.speed_slider = self._extracted_from_next_example_2('Speed', DEFAULT_SPEED)

  def intervening_function(self):
    if True:
      pass

  def next_example(self):
    self.force_slider = self._extracted_from_next_example_2('Force', DEFAULT_FORCE)

  def _extracted_from_next_example_2(self, label, arg1):
    result = Scale(self.master, from_=1, to=10, orient=HORIZONTAL, label=label)
    result.pack()
    result.set(arg1)
    result.configure(background='white')
    return result

Explanation:

Do not Repeat Yourself (DRY) is an important tenet of writing clean, maintainable code. Duplicated code bloats the code base, making it harder to read and understand. It often also leads to bugs. Where changes are made in only some of the duplicated areas unintended behaviour will often arise.

One of the main ways to remove duplication is to extract the common areas into another method and call that. Sourcery can detect areas of duplicate code that are in different methods in the same class and extract them. It is recommended that you then rename the extracted function and any arguments that have not been automatically named. In the above example a suitable method name would be create_slider, and arg1 would be default_value.

Class-level refactorigns such as this one run on file open and file save, rather than on every change to the code.