languages: Fix Pyright ignoring toolchain when LSP settings are configured

[lingyaochu]

Objective

Closes #55936
Helps #57288

There is a strange behavior for Python users when using basedpyright or pyright as the language server. As reported in #55936, when no settings are configured in lsp.basedpyright.settings, the language server correctly receives toolchain information discovered by Zed:

{
  "venvPath": ".",
  "venv": ".venv",
  "python": {
    "pythonPath": "/home/xin/works/test/test_python/.venv/bin/python",
    "defaultInterpreterPath": "/home/xin/works/test/test_python/.venv/bin/python"
  },
  "basedpyright.analysis": {
    "typeCheckingMode": "standard"
  },
  "basedpyright.disableOrganizeImports": true
}

However, when the user configures any other settings in lsp.basedpyright.settings, the toolchain information is silently lost. For example, with the following settings.json:

{
  "lsp": {
    "basedpyright": {
      "settings": {
        "analysis": {
          "diagnosticMode": "workspace",
          "typeCheckingMode": "standard",
          "inlayHints.callArgumentNames": true,
          "inlayHints.variableTypes": true,
        },
      },
    }
  }
}

The final configuration sent to the language server becomes:

{
  "analysis": {
    "diagnosticMode": "workspace",
    "typeCheckingMode": "standard",
    "inlayHints.callArgumentNames": true,
    "inlayHints.variableTypes": true
  }
}

No toolchain information is passed, so the language server ignores the user's selected Python environment and falls back to whatever virtual environment it discovers on its own. To make toolchain selection work, users currently have to manually configure virtual environment settings themselves (as noted in #57288 (comment)).

This issue was introduced in #48262, which aimed to make the virtual environment used by basedpyright/pyright configurable. The core logic is the should_insert_toolchain closure, originally designed to check whether Zed should inject the detected toolchain into the language server configuration. The intent was: if the user has already configured a virtual environment in the language server settings, skip the injection.

zed/crates/languages/src/python.rs

Lines 2115 to 2128 in 2c346f6

	// If we have a detected toolchain, configure Pyright to use it
	let should_insert_toolchain = || {
	user_settings.as_object().is_none_or(|object| {
	[
	"venvPath",
	"venv",
	"python",
	"pythonPath",
	"defaultInterpreterPath",
	]
	.into_iter()
	.any(|known_key| object.contains_key(known_key))
	})
	};

However, the original logic was inverted — it injected the toolchain when the user had no settings at all or when they had configured virtual environment keys. This meant that when the user had LSP settings but no virtual environment configuration, toolchain injection was skipped, as reported in #55936.

Solution

Change the logic defined in should_insert_toolchain closure, instead of insert toolchain when detected virtual environment settings, now we insert toolchain when no virtual environment settings is detected.

Testing

Tested locally. The logic change is simple, should be easy for review.

Self-Review Checklist:

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content adheres to Zed's UI standards (UX/UI and icon guidelines)
• Tests cover the new/changed behavior
• Performance impact has been considered and is acceptable

---

Release Notes:

• Fixed toolchain selection being ignored when Pyright or Basedpyright settings are configured without specifying a Python interpreter path

[zed-industries-bot]

	Messages
📖	This PR includes links to the following GitHub Issues: #57288 If this PR aims to close an issue, please include a Closes #ISSUE line at the top of the PR body.

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[Veykril]

Thanks!