Open Source VS Code Python Language Server Dies, Replaced by Proprietary Pylance

Microsoft officially pounded the last nail into the open source Microsoft Python Language Server coffin, replacing it with the company's proprietary Pylance extension for coding with Python in Visual Studio Code.

The move affects millions of developers, as the Python extension is by far the most popular tool in the VS Code Marketplace, having been downloaded nearly 50 million times, about twice as much as the next most popular extension: Jupyter.

While the company isn't forcing users to switch to its new proprietary language server -- pointing to an open source alternative -- it's the new default.

"In September, we announced that the Microsoft Python Language Server would be reaching end of life as of the November 2021 release of the Python extension," said Savannah Ostrowski, program manager, Pylance, in a Nov. 4 blog post. "Since then, we've encouraged our remaining legacy language server users to switch to a supported language server -- either Pylance (our default and recommended language support) or Jedi.

"As of today's release, all remaining users who have not chosen a new language server have been flipped to the default language support for Python in Visual Studio Code -- Pylance. If at any point you want to try a different language server, you can do that by updating your settings."

Although Microsoft said the new language server is more performant and feature-rich, the move goes against the grain of the company's fairly recent embrace of the open source movement after years of being viewed by many as a proprietary corporate bully with a closed, tightly controlled development ecosystem.

The open source implications of the switch were brought to the fore in June 2020 when a GitHub issue in the Pylance repo was posted with this entreaty: "Please consider making Pylance open source so other editors can leverage it."

Ostrowski's reply read: "We appreciate your suggestion, but we are not planning to make Pylance open source at this moment.

"Pylance is a completely new language server implementation,  with significant enhancements, and is planned to be included in proprietary service offerings.  A large amount of the code that powers Pylance is available as open-source in the Pyright type checker."

The back-and-forth discussion continued for about a month and a half before Microsoft locked it as resolved.

Besides the announcement that the Microsoft Python Language Server had reached end of life, the post about the last dev cycle mostly concerns housekeeping, closing off a bunch of issues.

However, Ostrowski did say: "We would like to thank all participants of the Grace Hoper Celebration's Open Source Day who contributed to the Python extension last October."

About the Author

David Ramel is an editor and writer for Converge360.

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