From 7bc3616ed836abbdfd98dde9163b76248571ff80 Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Fri, 22 Dec 2023 19:58:20 +0100
Subject: [PATCH 01/11] fix(#2519): diagnostics overhaul

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/diagnostics.lua      | 76 ++++++++++++++++++------------
 lua/nvim-tree/node.lua             |  1 +
 lua/nvim-tree/renderer/builder.lua |  2 +
 3 files changed, 48 insertions(+), 31 deletions(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 93c689634a9..b6d511bf771 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -1,6 +1,5 @@
 local utils = require "nvim-tree.utils"
 local view = require "nvim-tree.view"
-local core = require "nvim-tree.core"
 local log = require "nvim-tree.log"
 
 local M = {}
@@ -12,6 +11,16 @@ local severity_levels = {
   Hint = 4,
 }
 
+--- A dictionary tree containing buffer-severity mappings.
+---@type table
+local buffer_severity_dict = {}
+
+---@param path string
+---@return string
+local function uniformize_path(path)
+  return utils.canonical_path(path:gsub("\\", "/"))
+end
+
 ---@return table
 local function from_nvim_lsp()
   local buffer_severity = {}
@@ -25,7 +34,7 @@ local function from_nvim_lsp()
     for _, diagnostic in ipairs(vim.diagnostic.get(nil, { severity = M.severity })) do
       local buf = diagnostic.bufnr
       if vim.api.nvim_buf_is_valid(buf) then
-        local bufname = vim.api.nvim_buf_get_name(buf)
+        local bufname = uniformize_path(vim.api.nvim_buf_get_name(buf))
         local lowest_severity = buffer_severity[bufname]
         if not lowest_severity or diagnostic.severity < lowest_severity then
           buffer_severity[bufname] = diagnostic.severity
@@ -67,7 +76,7 @@ local function from_coc()
   local buffer_severity = {}
   for bufname, severity in pairs(diagnostics) do
     if is_severity_in_range(severity, M.severity) then
-      buffer_severity[bufname] = severity
+      buffer_severity[uniformize_path(bufname)] = severity
     end
   end
 
@@ -79,47 +88,52 @@ local function is_using_coc()
 end
 
 function M.update()
-  if not M.enable or not core.get_explorer() or not view.is_buf_valid(view.get_bufnr()) then
+  if not M.enable then
     return
   end
   utils.debounce("diagnostics", M.debounce_delay, function()
     local profile = log.profile_start "diagnostics update"
-    log.line("diagnostics", "update")
-
-    local buffer_severity
     if is_using_coc() then
-      buffer_severity = from_coc()
+      buffer_severity_dict = from_coc()
     else
-      buffer_severity = from_nvim_lsp()
+      buffer_severity_dict = from_nvim_lsp()
     end
-
-    local nodes_by_line = utils.get_nodes_by_line(core.get_explorer().nodes, core.get_nodes_starting_line())
-    for _, node in pairs(nodes_by_line) do
-      node.diag_status = nil
+    log.node("diagnostics", buffer_severity_dict, "update")
+    log.profile_end(profile)
+    if view.is_buf_valid(view.get_bufnr()) then
+      require("nvim-tree.renderer").draw()
     end
+  end)
+end
+
+---@param node Node
+function M.update_node_severity_level(node)
+  if not M.enable then
+    return
+  end
 
-    for bufname, severity in pairs(buffer_severity) do
-      local bufpath = utils.canonical_path(bufname)
-      log.line("diagnostics", " bufpath '%s' severity %d", bufpath, severity)
-      if 0 < severity and severity < 5 then
-        for line, node in pairs(nodes_by_line) do
-          local nodepath = utils.canonical_path(node.absolute_path)
-          log.line("diagnostics", "  %d checking nodepath '%s'", line, nodepath)
-
-          local node_contains_buf = vim.startswith(bufpath:gsub("\\", "/"), nodepath:gsub("\\", "/") .. "/")
-          if M.show_on_dirs and node_contains_buf and (not node.open or M.show_on_open_dirs) then
-            log.line("diagnostics", " matched fold node '%s'", node.absolute_path)
-            node.diag_status = severity
-          elseif nodepath == bufpath then
-            log.line("diagnostics", " matched file node '%s'", node.absolute_path)
-            node.diag_status = severity
+  local is_folder = node.nodes ~= nil
+  local nodepath = uniformize_path(node.absolute_path)
+
+  if is_folder then
+    local max_severity = nil
+    if M.show_on_dirs and (not node.open or M.show_on_open_dirs) then
+      for bufname, severity in pairs(buffer_severity_dict) do
+        local node_contains_buf = vim.startswith(bufname, nodepath .. "/")
+        if node_contains_buf then
+          if severity == M.severity.max then
+            max_severity = severity
+            break
+          else
+            max_severity = math.min(max_severity or severity, severity)
           end
         end
       end
     end
-    log.profile_end(profile)
-    require("nvim-tree.renderer").draw()
-  end)
+    node.diag_status = max_severity
+  else
+    node.diag_status = buffer_severity_dict[nodepath]
+  end
 end
 
 function M.setup(opts)
diff --git a/lua/nvim-tree/node.lua b/lua/nvim-tree/node.lua
index 55ee1942dc4..19bf4449eb3 100644
--- a/lua/nvim-tree/node.lua
+++ b/lua/nvim-tree/node.lua
@@ -17,6 +17,7 @@
 ---@field parent DirNode
 ---@field type string
 ---@field watcher function|nil
+---@field diag_status integer|nil
 
 ---@class DirNode: BaseNode
 ---@field has_children boolean
diff --git a/lua/nvim-tree/renderer/builder.lua b/lua/nvim-tree/renderer/builder.lua
index bfd72f7aac1..be60872688a 100644
--- a/lua/nvim-tree/renderer/builder.lua
+++ b/lua/nvim-tree/renderer/builder.lua
@@ -413,6 +413,8 @@ end
 function Builder:_build_line(node, idx, num_children, unloaded_bufnr)
   local copy_paste = require "nvim-tree.actions.fs.copy-paste"
 
+  require("nvim-tree.diagnostics").update_node_severity_level(node)
+
   -- various components
   local indent_markers = pad.get_indent_markers(self.depth, idx, num_children, node, self.markers)
   local arrows = pad.get_arrows(node)

From 2baf3dada46e90a712ae295879c1f109c6aae5a6 Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Sat, 23 Dec 2023 01:59:50 +0100
Subject: [PATCH 02/11] fix: Properly filter diagnostics from coc

Also, while we're at it, refactor the lsp function for consistency.
There should be no functional change, just cosmetic.

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/diagnostics.lua | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index b6d511bf771..0cf15b54253 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -35,10 +35,9 @@ local function from_nvim_lsp()
       local buf = diagnostic.bufnr
       if vim.api.nvim_buf_is_valid(buf) then
         local bufname = uniformize_path(vim.api.nvim_buf_get_name(buf))
-        local lowest_severity = buffer_severity[bufname]
-        if not lowest_severity or diagnostic.severity < lowest_severity then
-          buffer_severity[bufname] = diagnostic.severity
-        end
+        local severity = diagnostic.severity
+        local highest_severity = buffer_severity[bufname] or severity
+        buffer_severity[bufname] = math.min(highest_severity, severity)
       end
     end
   end
@@ -64,19 +63,13 @@ local function from_coc()
     return {}
   end
 
-  local diagnostics = {}
+  local buffer_severity = {}
   for _, diagnostic in ipairs(diagnostic_list) do
-    local bufname = diagnostic.file
+    local bufname = uniformize_path(diagnostic.file)
     local coc_severity = severity_levels[diagnostic.severity]
-
-    local serverity = diagnostics[bufname] or vim.diagnostic.severity.HINT
-    diagnostics[bufname] = math.min(coc_severity, serverity)
-  end
-
-  local buffer_severity = {}
-  for bufname, severity in pairs(diagnostics) do
-    if is_severity_in_range(severity, M.severity) then
-      buffer_severity[uniformize_path(bufname)] = severity
+    local highest_severity = buffer_severity[bufname] or coc_severity
+    if is_severity_in_range(highest_severity, M.severity) then
+      buffer_severity[bufname] = math.min(highest_severity, coc_severity)
     end
   end
 

From f30a8f6862ed9ebdccb549328fa6baaa2c6428b1 Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Sun, 24 Dec 2023 15:17:40 +0100
Subject: [PATCH 03/11] Assign diagnostic version per node to reduce overhead

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/actions/moves/item.lua          |  4 +-
 lua/nvim-tree/diagnostics.lua                 | 79 +++++++++++++------
 lua/nvim-tree/node.lua                        |  2 +-
 lua/nvim-tree/renderer/builder.lua            |  2 -
 .../renderer/components/diagnostics.lua       |  9 ++-
 5 files changed, 67 insertions(+), 29 deletions(-)

diff --git a/lua/nvim-tree/actions/moves/item.lua b/lua/nvim-tree/actions/moves/item.lua
index 9375ef5f4dc..bf72c0ea2df 100644
--- a/lua/nvim-tree/actions/moves/item.lua
+++ b/lua/nvim-tree/actions/moves/item.lua
@@ -3,6 +3,7 @@ local view = require "nvim-tree.view"
 local core = require "nvim-tree.core"
 local lib = require "nvim-tree.lib"
 local explorer_node = require "nvim-tree.explorer.node"
+local diagnostics = require "nvim-tree.diagnostics"
 
 local M = {}
 
@@ -33,7 +34,8 @@ function M.fn(opts)
         local git_status = explorer_node.get_git_status(node)
         valid = git_status ~= nil and (not opts.skip_gitignored or git_status[1] ~= "!!")
       elseif opts.what == "diag" then
-        valid = node.diag_status ~= nil
+        local diag_status = diagnostics.get_diag_status(node)
+        valid = diag_status ~= nil and diag_status.value ~= nil
       elseif opts.what == "opened" then
         valid = vim.fn.bufloaded(node.absolute_path) ~= 0
       end
diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 0cf15b54253..8028fe76d0b 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -11,10 +11,18 @@ local severity_levels = {
   Hint = 4,
 }
 
+---@class DiagStatus
+---@field value integer|nil
+---@field cache_version integer
+
 --- A dictionary tree containing buffer-severity mappings.
 ---@type table
 local buffer_severity_dict = {}
 
+--- The cache version number of the buffer-severity mappings.
+---@type integer
+local BUFFER_SEVERITY_VERSION = 0
+
 ---@param path string
 ---@return string
 local function uniformize_path(path)
@@ -80,6 +88,31 @@ local function is_using_coc()
   return vim.g.coc_service_initialized == 1
 end
 
+---@param node Node
+---@return DiagStatus
+local function from_cache(node)
+  local nodepath = uniformize_path(node.absolute_path)
+  local max_severity = nil
+  if not node.nodes then
+    -- direct cache hit for files
+    max_severity = buffer_severity_dict[nodepath]
+  else
+    -- dirs should be searched in the list of cached buffer names by prefix
+    for bufname, severity in pairs(buffer_severity_dict) do
+      local node_contains_buf = vim.startswith(bufname, nodepath .. "/")
+      if node_contains_buf then
+        if severity == M.severity.max then
+          max_severity = severity
+          break
+        else
+          max_severity = math.min(max_severity or severity, severity)
+        end
+      end
+    end
+  end
+  return { value = max_severity, cache_version = BUFFER_SEVERITY_VERSION }
+end
+
 function M.update()
   if not M.enable then
     return
@@ -91,6 +124,7 @@ function M.update()
     else
       buffer_severity_dict = from_nvim_lsp()
     end
+    BUFFER_SEVERITY_VERSION = BUFFER_SEVERITY_VERSION + 1
     log.node("diagnostics", buffer_severity_dict, "update")
     log.profile_end(profile)
     if view.is_buf_valid(view.get_bufnr()) then
@@ -100,33 +134,34 @@ function M.update()
 end
 
 ---@param node Node
-function M.update_node_severity_level(node)
+---@return DiagStatus|nil
+function M.get_diag_status(node)
   if not M.enable then
-    return
+    return nil
   end
 
-  local is_folder = node.nodes ~= nil
-  local nodepath = uniformize_path(node.absolute_path)
+  -- dir but we shouldn't show on dirs at all
+  if node.nodes ~= nil and not M.show_on_dirs then
+    return nil
+  end
 
-  if is_folder then
-    local max_severity = nil
-    if M.show_on_dirs and (not node.open or M.show_on_open_dirs) then
-      for bufname, severity in pairs(buffer_severity_dict) do
-        local node_contains_buf = vim.startswith(bufname, nodepath .. "/")
-        if node_contains_buf then
-          if severity == M.severity.max then
-            max_severity = severity
-            break
-          else
-            max_severity = math.min(max_severity or severity, severity)
-          end
-        end
-      end
-    end
-    node.diag_status = max_severity
-  else
-    node.diag_status = buffer_severity_dict[nodepath]
+  -- here, we do a lazy update of the diagnostic status carried by the node.
+  -- This is by design, as diagnostics and nodes live in completely separate
+  -- worlds, and this module is the link between the two
+  if not node.diag_status or node.diag_status.cache_version < BUFFER_SEVERITY_VERSION then
+    node.diag_status = from_cache(node)
+  end
+
+  -- file
+  if not node.nodes then
+    return node.diag_status
+  end
+
+  -- dir is closed or we should show on open_dirs
+  if not node.open or M.show_on_open_dirs then
+    return node.diag_status
   end
+  return nil
 end
 
 function M.setup(opts)
diff --git a/lua/nvim-tree/node.lua b/lua/nvim-tree/node.lua
index 19bf4449eb3..323fc53c4c4 100644
--- a/lua/nvim-tree/node.lua
+++ b/lua/nvim-tree/node.lua
@@ -17,7 +17,7 @@
 ---@field parent DirNode
 ---@field type string
 ---@field watcher function|nil
----@field diag_status integer|nil
+---@field diag_status DiagStatus|nil
 
 ---@class DirNode: BaseNode
 ---@field has_children boolean
diff --git a/lua/nvim-tree/renderer/builder.lua b/lua/nvim-tree/renderer/builder.lua
index be60872688a..bfd72f7aac1 100644
--- a/lua/nvim-tree/renderer/builder.lua
+++ b/lua/nvim-tree/renderer/builder.lua
@@ -413,8 +413,6 @@ end
 function Builder:_build_line(node, idx, num_children, unloaded_bufnr)
   local copy_paste = require "nvim-tree.actions.fs.copy-paste"
 
-  require("nvim-tree.diagnostics").update_node_severity_level(node)
-
   -- various components
   local indent_markers = pad.get_indent_markers(self.depth, idx, num_children, node, self.markers)
   local arrows = pad.get_arrows(node)
diff --git a/lua/nvim-tree/renderer/components/diagnostics.lua b/lua/nvim-tree/renderer/components/diagnostics.lua
index 3a145406e70..1fa864deac9 100644
--- a/lua/nvim-tree/renderer/components/diagnostics.lua
+++ b/lua/nvim-tree/renderer/components/diagnostics.lua
@@ -1,4 +1,5 @@
 local HL_POSITION = require("nvim-tree.enum").HL_POSITION
+local diagnostics = require "nvim-tree.diagnostics"
 
 local M = {
   HS_FILE = {},
@@ -17,10 +18,11 @@ function M.get_highlight(node)
   end
 
   local group
+  local diag_status = diagnostics.get_diag_status(node)
   if node.nodes then
-    group = M.HS_FOLDER[node.diag_status]
+    group = M.HS_FOLDER[diag_status and diag_status.value]
   else
-    group = M.HS_FILE[node.diag_status]
+    group = M.HS_FILE[diag_status and diag_status.value]
   end
 
   if group then
@@ -35,7 +37,8 @@ end
 ---@return HighlightedString|nil modified icon
 function M.get_icon(node)
   if node and M.config.diagnostics.enable and M.config.renderer.icons.show.diagnostics then
-    return M.ICON[node.diag_status]
+    local diag_status = diagnostics.get_diag_status(node)
+    return M.ICON[diag_status and diag_status.value]
   end
 end
 

From 74130416300b1e33569c9bf908f3a8e2912ec8e6 Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Sun, 24 Dec 2023 16:04:36 +0100
Subject: [PATCH 04/11] Require renderer once

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/diagnostics.lua | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 8028fe76d0b..b56cb260470 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -1,6 +1,7 @@
 local utils = require "nvim-tree.utils"
 local view = require "nvim-tree.view"
 local log = require "nvim-tree.log"
+local renderer = require "nvim-tree.renderer"
 
 local M = {}
 
@@ -128,7 +129,7 @@ function M.update()
     log.node("diagnostics", buffer_severity_dict, "update")
     log.profile_end(profile)
     if view.is_buf_valid(view.get_bufnr()) then
-      require("nvim-tree.renderer").draw()
+      renderer.draw()
     end
   end)
 end

From e3c90fd16ca553218715f02441bda4ce0b8a0460 Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Mon, 25 Dec 2023 11:25:01 +0100
Subject: [PATCH 05/11] Revert "Require renderer once"

Causes circular requires after the previous commit.

This reverts commit 74130416300b1e33569c9bf908f3a8e2912ec8e6.
---
 lua/nvim-tree/diagnostics.lua | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index b56cb260470..8028fe76d0b 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -1,7 +1,6 @@
 local utils = require "nvim-tree.utils"
 local view = require "nvim-tree.view"
 local log = require "nvim-tree.log"
-local renderer = require "nvim-tree.renderer"
 
 local M = {}
 
@@ -129,7 +128,7 @@ function M.update()
     log.node("diagnostics", buffer_severity_dict, "update")
     log.profile_end(profile)
     if view.is_buf_valid(view.get_bufnr()) then
-      renderer.draw()
+      require("nvim-tree.renderer").draw()
     end
   end)
 end

From b8079fbf7bbd499085f82f1c6156b0618697fd88 Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Sun, 24 Dec 2023 15:55:46 +0100
Subject: [PATCH 06/11] Rename `buffer_severity_dict` to `BUFFER_SEVERITY`

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/diagnostics.lua | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 8028fe76d0b..461cb8ade90 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -15,9 +15,9 @@ local severity_levels = {
 ---@field value integer|nil
 ---@field cache_version integer
 
---- A dictionary tree containing buffer-severity mappings.
+--- The buffer-severity mappings derived during the last diagnostic list update.
 ---@type table
-local buffer_severity_dict = {}
+local BUFFER_SEVERITY = {}
 
 --- The cache version number of the buffer-severity mappings.
 ---@type integer
@@ -95,10 +95,10 @@ local function from_cache(node)
   local max_severity = nil
   if not node.nodes then
     -- direct cache hit for files
-    max_severity = buffer_severity_dict[nodepath]
+    max_severity = BUFFER_SEVERITY[nodepath]
   else
     -- dirs should be searched in the list of cached buffer names by prefix
-    for bufname, severity in pairs(buffer_severity_dict) do
+    for bufname, severity in pairs(BUFFER_SEVERITY) do
       local node_contains_buf = vim.startswith(bufname, nodepath .. "/")
       if node_contains_buf then
         if severity == M.severity.max then
@@ -120,12 +120,12 @@ function M.update()
   utils.debounce("diagnostics", M.debounce_delay, function()
     local profile = log.profile_start "diagnostics update"
     if is_using_coc() then
-      buffer_severity_dict = from_coc()
+      BUFFER_SEVERITY = from_coc()
     else
-      buffer_severity_dict = from_nvim_lsp()
+      BUFFER_SEVERITY = from_nvim_lsp()
     end
     BUFFER_SEVERITY_VERSION = BUFFER_SEVERITY_VERSION + 1
-    log.node("diagnostics", buffer_severity_dict, "update")
+    log.node("diagnostics", BUFFER_SEVERITY, "update")
     log.profile_end(profile)
     if view.is_buf_valid(view.get_bufnr()) then
       require("nvim-tree.renderer").draw()

From e6f343a6d44d27e24ecf203f165c75902c39f30a Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Mon, 25 Dec 2023 18:10:23 +0100
Subject: [PATCH 07/11] Log diagnostics update properly

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/diagnostics.lua | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 461cb8ade90..13cd1b00389 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -125,7 +125,11 @@ function M.update()
       BUFFER_SEVERITY = from_nvim_lsp()
     end
     BUFFER_SEVERITY_VERSION = BUFFER_SEVERITY_VERSION + 1
-    log.node("diagnostics", BUFFER_SEVERITY, "update")
+    if log.enabled("diagnostics") then
+      for bufname, severity in pairs(BUFFER_SEVERITY) do
+        log.line("diagnostics", "Indexing bufname '%s' with severity %d", bufname, severity)
+      end
+    end
     log.profile_end(profile)
     if view.is_buf_valid(view.get_bufnr()) then
       require("nvim-tree.renderer").draw()

From a15c8a90d895f5e32e80146ac842a03b486a40f4 Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Mon, 25 Dec 2023 19:32:07 +0100
Subject: [PATCH 08/11] Implement error handling for coc.nvim

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/diagnostics.lua | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 13cd1b00389..983289388eb 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -60,14 +60,31 @@ local function is_severity_in_range(severity, config)
   return config.max <= severity and severity <= config.min
 end
 
+---@param err string
+local function handle_coc_exception(err)
+  log.line("diagnostics", "handle_coc_exception: %s", vim.inspect(err))
+  local notify = true
+
+  -- avoid distractions on interrupts (CTRL-C)
+  if err:find("Vim:Interrupt") then
+    notify = false
+  end
+
+  if notify then
+    require("nvim-tree.notify").error("Diagnostics update from coc.nvim failed. " .. vim.inspect(err))
+  end
+end
+
 ---@return table
 local function from_coc()
   if vim.g.coc_service_initialized ~= 1 then
     return {}
   end
 
-  local diagnostic_list = vim.fn.CocAction "diagnosticList"
-  if type(diagnostic_list) ~= "table" or vim.tbl_isempty(diagnostic_list) then
+  local ok, diagnostic_list = xpcall(function()
+    return vim.fn.CocAction("diagnosticList")
+  end, handle_coc_exception)
+  if not ok or type(diagnostic_list) ~= "table" or vim.tbl_isempty(diagnostic_list) then
     return {}
   end
 

From b05f7e3d1125b234525449205d2e7c9047558cea Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Tue, 26 Dec 2023 09:18:54 +0100
Subject: [PATCH 09/11] CI style fixes

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/diagnostics.lua | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 983289388eb..6051ad0128e 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -66,7 +66,7 @@ local function handle_coc_exception(err)
   local notify = true
 
   -- avoid distractions on interrupts (CTRL-C)
-  if err:find("Vim:Interrupt") then
+  if err:find "Vim:Interrupt" then
     notify = false
   end
 
@@ -82,7 +82,7 @@ local function from_coc()
   end
 
   local ok, diagnostic_list = xpcall(function()
-    return vim.fn.CocAction("diagnosticList")
+    return vim.fn.CocAction "diagnosticList"
   end, handle_coc_exception)
   if not ok or type(diagnostic_list) ~= "table" or vim.tbl_isempty(diagnostic_list) then
     return {}
@@ -142,7 +142,7 @@ function M.update()
       BUFFER_SEVERITY = from_nvim_lsp()
     end
     BUFFER_SEVERITY_VERSION = BUFFER_SEVERITY_VERSION + 1
-    if log.enabled("diagnostics") then
+    if log.enabled "diagnostics" then
       for bufname, severity in pairs(BUFFER_SEVERITY) do
         log.line("diagnostics", "Indexing bufname '%s' with severity %d", bufname, severity)
       end

From d7bd3598fc04ad9a2c2d280e5ef2901506f8f691 Mon Sep 17 00:00:00 2001
From: iusmac <iusico.maxim@libero.it>
Date: Thu, 28 Dec 2023 17:31:44 +0100
Subject: [PATCH 10/11] Capture `Keyboard interrupt` when handling coc
 exceptions

Signed-off-by: iusmac <iusico.maxim@libero.it>
---
 lua/nvim-tree/diagnostics.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 6051ad0128e..a4286b714de 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -66,7 +66,7 @@ local function handle_coc_exception(err)
   local notify = true
 
   -- avoid distractions on interrupts (CTRL-C)
-  if err:find "Vim:Interrupt" then
+  if err:find "Vim:Interrupt" or err:find "Keyboard interrupt" then
     notify = false
   end
 

From c37c895a42e4a3995829480729a6a544a5b2e3fb Mon Sep 17 00:00:00 2001
From: Alexander Courtis <alex@courtis.org>
Date: Sat, 30 Dec 2023 14:04:45 +1100
Subject: [PATCH 11/11] add more doc

---
 lua/nvim-tree/diagnostics.lua | 65 ++++++++++++++++++++++-------------
 1 file changed, 42 insertions(+), 23 deletions(-)

diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index a4286b714de..6ca13c9c067 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -4,24 +4,32 @@ local log = require "nvim-tree.log"
 
 local M = {}
 
-local severity_levels = {
+---TODO add "$VIMRUNTIME" to "workspace.library" and use the @enum instead of this integer
+---@alias lsp.DiagnosticSeverity integer
+
+---COC severity level strings to LSP severity levels
+---@enum COC_SEVERITY_LEVELS
+local COC_SEVERITY_LEVELS = {
   Error = 1,
   Warning = 2,
   Information = 3,
   Hint = 4,
 }
 
+---Absolute Node path to LSP severity level
+---@alias NodeSeverities table<string, lsp.DiagnosticSeverity>
+
 ---@class DiagStatus
----@field value integer|nil
+---@field value lsp.DiagnosticSeverity|nil
 ---@field cache_version integer
 
 --- The buffer-severity mappings derived during the last diagnostic list update.
----@type table
-local BUFFER_SEVERITY = {}
+---@type NodeSeverities
+local NODE_SEVERITIES = {}
 
---- The cache version number of the buffer-severity mappings.
+---The cache version number of the buffer-severity mappings.
 ---@type integer
-local BUFFER_SEVERITY_VERSION = 0
+local NODE_SEVERITIES_VERSION = 0
 
 ---@param path string
 ---@return string
@@ -29,7 +37,8 @@ local function uniformize_path(path)
   return utils.canonical_path(path:gsub("\\", "/"))
 end
 
----@return table
+---Marshal severities from LSP. Does nothing when LSP disabled.
+---@return NodeSeverities
 local function from_nvim_lsp()
   local buffer_severity = {}
 
@@ -53,13 +62,15 @@ local function from_nvim_lsp()
   return buffer_severity
 end
 
----@param severity integer
+---Severity is within diagnostics.severity.min, diagnostics.severity.max
+---@param severity lsp.DiagnosticSeverity
 ---@param config table
 ---@return boolean
 local function is_severity_in_range(severity, config)
   return config.max <= severity and severity <= config.min
 end
 
+---Handle any COC exceptions, preventing any propagation
 ---@param err string
 local function handle_coc_exception(err)
   log.line("diagnostics", "handle_coc_exception: %s", vim.inspect(err))
@@ -75,9 +86,16 @@ local function handle_coc_exception(err)
   end
 end
 
----@return table
+---COC service initialized
+---@return boolean
+local function is_using_coc()
+  return vim.g.coc_service_initialized == 1
+end
+
+---Marshal severities from COC. Does nothing when COC service not started.
+---@return NodeSeverities
 local function from_coc()
-  if vim.g.coc_service_initialized ~= 1 then
+  if not is_using_coc() then
     return {}
   end
 
@@ -91,7 +109,7 @@ local function from_coc()
   local buffer_severity = {}
   for _, diagnostic in ipairs(diagnostic_list) do
     local bufname = uniformize_path(diagnostic.file)
-    local coc_severity = severity_levels[diagnostic.severity]
+    local coc_severity = COC_SEVERITY_LEVELS[diagnostic.severity]
     local highest_severity = buffer_severity[bufname] or coc_severity
     if is_severity_in_range(highest_severity, M.severity) then
       buffer_severity[bufname] = math.min(highest_severity, coc_severity)
@@ -101,10 +119,7 @@ local function from_coc()
   return buffer_severity
 end
 
-local function is_using_coc()
-  return vim.g.coc_service_initialized == 1
-end
-
+---Maybe retrieve severity level from the cache
 ---@param node Node
 ---@return DiagStatus
 local function from_cache(node)
@@ -112,10 +127,10 @@ local function from_cache(node)
   local max_severity = nil
   if not node.nodes then
     -- direct cache hit for files
-    max_severity = BUFFER_SEVERITY[nodepath]
+    max_severity = NODE_SEVERITIES[nodepath]
   else
     -- dirs should be searched in the list of cached buffer names by prefix
-    for bufname, severity in pairs(BUFFER_SEVERITY) do
+    for bufname, severity in pairs(NODE_SEVERITIES) do
       local node_contains_buf = vim.startswith(bufname, nodepath .. "/")
       if node_contains_buf then
         if severity == M.severity.max then
@@ -127,9 +142,11 @@ local function from_cache(node)
       end
     end
   end
-  return { value = max_severity, cache_version = BUFFER_SEVERITY_VERSION }
+  return { value = max_severity, cache_version = NODE_SEVERITIES_VERSION }
 end
 
+---Fired on DiagnosticChanged and CocDiagnosticChanged events:
+---debounced retrieval, cache update, version increment and draw
 function M.update()
   if not M.enable then
     return
@@ -137,13 +154,13 @@ function M.update()
   utils.debounce("diagnostics", M.debounce_delay, function()
     local profile = log.profile_start "diagnostics update"
     if is_using_coc() then
-      BUFFER_SEVERITY = from_coc()
+      NODE_SEVERITIES = from_coc()
     else
-      BUFFER_SEVERITY = from_nvim_lsp()
+      NODE_SEVERITIES = from_nvim_lsp()
     end
-    BUFFER_SEVERITY_VERSION = BUFFER_SEVERITY_VERSION + 1
+    NODE_SEVERITIES_VERSION = NODE_SEVERITIES_VERSION + 1
     if log.enabled "diagnostics" then
-      for bufname, severity in pairs(BUFFER_SEVERITY) do
+      for bufname, severity in pairs(NODE_SEVERITIES) do
         log.line("diagnostics", "Indexing bufname '%s' with severity %d", bufname, severity)
       end
     end
@@ -154,6 +171,8 @@ function M.update()
   end)
 end
 
+---Maybe retrieve diagnostic status for a node.
+---Returns cached value when node's version matches.
 ---@param node Node
 ---@return DiagStatus|nil
 function M.get_diag_status(node)
@@ -169,7 +188,7 @@ function M.get_diag_status(node)
   -- here, we do a lazy update of the diagnostic status carried by the node.
   -- This is by design, as diagnostics and nodes live in completely separate
   -- worlds, and this module is the link between the two
-  if not node.diag_status or node.diag_status.cache_version < BUFFER_SEVERITY_VERSION then
+  if not node.diag_status or node.diag_status.cache_version < NODE_SEVERITIES_VERSION then
     node.diag_status = from_cache(node)
   end