feat: Add Experimental Option to Enable Window-Local Extmarks (#163)

* feat(diagnostic): Only show diagnostics on current window

Closes #127

* chore(extmarks): Move module-level function to proper location

This also adds a luadoc, like the other functions have

* fix(extmarks): Don't link window diagnostics on startup

This bug occured if the user initially has 2 windows with the same
buffer in them when the plugin starts up, resulting in "mirroring" the
diagnostics

* feat(config): Add flag to for enabling window-local extmarks

* docs(readme): Document how to use `use_window_local_extmarks`

Author: bramdelta

README.md

@@ -252,6 +252,13 @@ require("tiny-inline-diagnostic").setup({
 
         -- Automatically disable diagnostics when opening diagnostic float windows
         override_open_float = false,
+
+        -- Experimental options, subject to misbehave in future NeoVim releases
+        experimental = {
+          -- Make diagnostics not mirror across windows containing the same buffer
+          -- See: https://github.com/rachartier/tiny-inline-diagnostic.nvim/issues/127
+          use_window_local_extmarks = false,
+        },
     },
 })
 ```

lua/tiny-inline-diagnostic/autocmds.lua

@@ -91,13 +91,15 @@ end
 ---@param throttled_apply function
 ---@param direct_apply function
 ---@param on_diagnostic_change function
+---@param on_window_change function
 function M.setup_buffer_autocmds(
   autocmd_ns,
   opts,
   bufnr,
   throttled_apply,
   direct_apply,
-  on_diagnostic_change
+  on_diagnostic_change,
+  on_window_change
 )
   if not vim.api.nvim_buf_is_valid(bufnr) or attached_buffers[bufnr] then
     return
@@ -156,6 +158,14 @@ function M.setup_buffer_autocmds(
     end,
     desc = "Update diagnostics on window resize",
   })
+
+  if opts.options.experimental.use_window_local_extmarks then
+    vim.api.nvim_create_autocmd("WinEnter", {
+      group = autocmd_ns,
+      callback = on_window_change,
+      desc = "Sync namespace window on window change",
+    })
+  end
 end
 
 ---@return number

lua/tiny-inline-diagnostic/diagnostic.lua

@@ -2,6 +2,7 @@ local M = {}
 
 local autocmds = require("tiny-inline-diagnostic.autocmds")
 local cache = require("tiny-inline-diagnostic.cache")
+local extmarks = require("tiny-inline-diagnostic.extmarks")
 local filter = require("tiny-inline-diagnostic.filter")
 local handlers = require("tiny-inline-diagnostic.handlers")
 local renderer = require("tiny-inline-diagnostic.renderer")
@@ -50,14 +51,16 @@ function M.set_diagnostic_autocmds(opts)
 
       local on_diagnostic_change = handlers.build_diagnostic_change_handler(cache, opts)
       local on_mode_change = handlers.build_mode_change_handler(state, renderer, opts)
+      local on_window_change = extmarks.update_namespace_window
 
       autocmds.setup_buffer_autocmds(
         autocmd_ns,
         opts,
         event.buf,
         throttler.fn,
         direct_renderer,
-        on_diagnostic_change
+        on_diagnostic_change,
+        on_window_change
       )
       autocmds.setup_cursor_autocmds(autocmd_ns, opts, event.buf, throttler.fn, direct_renderer)
       autocmds.setup_mode_change_autocmds(autocmd_ns, event.buf, on_mode_change)
@@ -95,7 +98,6 @@ end
 
 function M.disable()
   state.user_disable()
-  local extmarks = require("tiny-inline-diagnostic.extmarks")
 
   vim.schedule(function()
     for _, bufnr in ipairs(vim.api.nvim_list_bufs()) do

lua/tiny-inline-diagnostic/extmarks.lua

@@ -80,6 +80,13 @@ function M.count_inlay_hints_characters(buf, linenr)
   return count
 end
 
+---Update the current namespace used for extmarks to only include the active window.
+---Note: this uses a currently experimental API call, and may break in future NeoVim releases.
+function M.update_namespace_window()
+  local current_window = vim.api.nvim_get_current_win()
+  vim.api.nvim__ns_set(DIAGNOSTIC_NAMESPACE, { wins = { current_window } })
+end
+
 -- Public API
 
 ---Clear extmarks from buffer

lua/tiny-inline-diagnostic/init.lua

@@ -7,6 +7,7 @@
 local M = {}
 
 local diag = require("tiny-inline-diagnostic.diagnostic")
+local extmarks = require("tiny-inline-diagnostic.extmarks")
 local hi = require("tiny-inline-diagnostic.highlights")
 local presets = require("tiny-inline-diagnostic.presets")
 
@@ -71,6 +72,9 @@ local default_config = {
     },
     override_open_float = false,
     overwrite_events = nil,
+    experimental = {
+      use_window_local_extmarks = false,
+    },
   },
   disabled_ft = {},
 }
@@ -135,6 +139,12 @@ function M.setup(opts)
 
   setup_colorscheme_handler(config)
   diag.set_diagnostic_autocmds(config)
+
+  -- Ensure the diagnostics are only linked to the current window on startup
+  -- This gets around a bug where having 2 windows with the same buffer on startup causes mirroring
+  if config.options.experimental.use_window_local_extmarks then
+    extmarks.update_namespace_window()
+  end
 end
 
 --- Change the blend and highlight settings dynamically.