lsp: add vim.lsp.diagnostic.set_qflist() function (#14831)

* Add vim.lsp.diagnostic.set_qflist() function
* replaces opts.open_loclist with unified opts.open

runtime/doc/lsp.txt

@@ -1470,12 +1470,36 @@ save({diagnostics}, {bufnr}, {client_id})          *vim.lsp.diagnostic.save()*
 save_extmarks({bufnr}, {client_id})
                 TODO: Documentation
 
+set_qflist({opts})                         *vim.lsp.diagnostic.set_qflist()*
+                Sets the quickfix list
+
+                Parameters: ~
+                    {opts}  table|nil Configuration table. Keys:
+                            • {open}: (boolean, default true)
+                              • Open quickfix list after set
+
+                            • {client_id}: (number)
+                              • If nil, will consider all clients attached to
+                                buffer.
+
+                            • {severity}: (DiagnosticSeverity)
+                              • Exclusive severity to consider. Overrides
+                                {severity_limit}
+
+                            • {severity_limit}: (DiagnosticSeverity)
+                              • Limit severity of diagnostics found. E.g.
+                                "Warning" means { "Error", "Warning" } will be
+                                valid.
+
+                            • {workspace}: (boolean, default true)
+                              • Set the list with workspace diagnostics
+
 set_loclist({opts})                         *vim.lsp.diagnostic.set_loclist()*
                 Sets the location list
 
                 Parameters: ~
                     {opts}  table|nil Configuration table. Keys:
-                            • {open_loclist}: (boolean, default true)
+                            • {open}: (boolean, default true)
                               • Open loclist after set
 
                             • {client_id}: (number)

runtime/lua/vim/lsp/diagnostic.lua

@@ -1249,10 +1249,10 @@ function M.reset(client_id, buffer_client_map)
   end)
 end
 
---- Sets the location list
+--- Gets diagnostics, converts them to quickfix/location list items, and applies the item_handler callback to the items.
+---@param item_handler function Callback to apply to the diagnostic items
+---@param command string|nil Command to execute after applying the item_handler
 ---@param opts table|nil Configuration table. Keys:
----         - {open_loclist}: (boolean, default true)
----             - Open loclist after set
 ---         - {client_id}: (number)
 ---             - If nil, will consider all clients attached to buffer.
 ---         - {severity}: (DiagnosticSeverity)
@@ -1261,9 +1261,8 @@ end
 ---             - Limit severity of diagnostics found. E.g. "Warning" means { "Error", "Warning" } will be valid.
 ---         - {workspace}: (boolean, default false)
 ---             - Set the list with workspace diagnostics
-function M.set_loclist(opts)
+local function apply_to_diagnostic_items(item_handler, command, opts)
   opts = opts or {}
-  local open_loclist = if_nil(opts.open_loclist, true)
   local current_bufnr = api.nvim_get_current_buf()
   local diags = opts.workspace and M.get_all(opts.client_id) or {
     [current_bufnr] = M.get(current_bufnr, opts.client_id)
@@ -1280,13 +1279,51 @@ function M.set_loclist(opts)
     return true
   end
   local items = util.diagnostics_to_items(diags, predicate)
-  local win_id = vim.api.nvim_get_current_win()
-  util.set_loclist(items, win_id)
-  if open_loclist then
-    vim.cmd [[lopen]]
+  item_handler(items)
+  if command then
+    vim.cmd(command)
   end
 end
 
+--- Sets the quickfix list
+---@param opts table|nil Configuration table. Keys:
+---         - {open}: (boolean, default true)
+---             - Open quickfix list after set
+---         - {client_id}: (number)
+---             - If nil, will consider all clients attached to buffer.
+---         - {severity}: (DiagnosticSeverity)
+---             - Exclusive severity to consider. Overrides {severity_limit}
+---         - {severity_limit}: (DiagnosticSeverity)
+---             - Limit severity of diagnostics found. E.g. "Warning" means { "Error", "Warning" } will be valid.
+---         - {workspace}: (boolean, default true)
+---             - Set the list with workspace diagnostics
+function M.set_qflist(opts)
+  opts = opts or {}
+  opts.workspace = if_nil(opts.workspace, true)
+  local open_qflist = if_nil(opts.open, true)
+  local command = open_qflist and [[copen]] or nil
+  apply_to_diagnostic_items(util.set_qflist, command, opts)
+end
+
+--- Sets the location list
+---@param opts table|nil Configuration table. Keys:
+---         - {open}: (boolean, default true)
+---             - Open loclist after set
+---         - {client_id}: (number)
+---             - If nil, will consider all clients attached to buffer.
+---         - {severity}: (DiagnosticSeverity)
+---             - Exclusive severity to consider. Overrides {severity_limit}
+---         - {severity_limit}: (DiagnosticSeverity)
+---             - Limit severity of diagnostics found. E.g. "Warning" means { "Error", "Warning" } will be valid.
+---         - {workspace}: (boolean, default false)
+---             - Set the list with workspace diagnostics
+function M.set_loclist(opts)
+  opts = opts or {}
+  local open_loclist = if_nil(opts.open, true)
+  local command = open_loclist and [[lopen]] or nil
+  apply_to_diagnostic_items(util.set_loclist, command, opts)
+end
+
 --- Disable diagnostics for the given buffer and client
 --- @param bufnr (optional, number): Buffer handle, defaults to current
 --- @param client_id (optional, number): Disable diagnostics for the given