Initialization

diff-lsp initializes itself by reading the most recent file in /tmp that matches the pattern diff_lsp_*. This file contains the context for the current diff session.

Tempfile Format

The initialization tempfile supports the following fields:

Root: <path>: (Required) The absolute path to the project root.
Worktree: <subfolder>: (Optional) A subfolder within the root to use as the working directory for backend LSP clients.
modified <file>, new file <file>, deleted <file>: Used to detect which languages should be activated based on file extensions.
diff --git ...: Standard git diff headers are also parsed to detect active languages.

Worktree Integration

Worktree integration allows diff-lsp to start backend LSP clients (like rust-analyzer or gopls) in a specific subfolder of your project instead of the root.

How it works

When diff-lsp reads the initialization tempfile, it looks for the Worktree: field.
If Worktree: <subfolder> is present, diff-lsp joins this subfolder with the Root path.
If the resulting path exists, diff-lsp uses this path as the current working directory when spawning backend LSP clients.
If the worktree subfolder does not exist, diff-lsp gracefully falls back to using the Root path.

This is particularly useful for monorepos or projects where the LSP should be scoped to a specific part of the codebase.