refactor(diagnostic)!: replace 'show_*' functions with 'open_float' (#16057)

'show_line_diagnostics()' and 'show_position_diagnostics()' are
almost identical; they differ only in the fact that the latter also
accepts a column to form a full position, rather than just a line. This
is not enough to justify two separate interfaces for this common
functionality.

Renaming this to simply 'show_diagnostics()' is one step forward, but
that is also not a good name as the '_diagnostics()' suffix is
redundant. However, we cannot name it simply 'show()' since that
function already exists with entirely different semantics.

Instead, combine these two into a single 'open_float()' function that
handles all of the cases of showing diagnostics in a floating window.
Also add a "float" key to 'vim.diagnostic.config()' to provide global
values of configuration options that can be overridden ephemerally.
This makes the float API consistent with the rest of the diagnostic API.

BREAKING CHANGE

1 files changed, 12 insertions, 9 deletions

diff --git a/runtime/lua/vim/lsp/diagnostic.lua b/runtime/lua/vim/lsp/diagnostic.lua
index 0e63c0dd29..8fb7971c5a 100644
--- a/runtime/lua/vim/lsp/diagnostic.lua
+++ b/runtime/lua/vim/lsp/diagnostic.lua
@@ -551,14 +551,15 @@ end
 ---@param position table|nil The (0,0)-indexed position
 ---@return table {popup_bufnr, win_id}
 function M.show_position_diagnostics(opts, buf_nr, position)
-  if opts then
-    if opts.severity then
-      opts.severity = severity_lsp_to_vim(opts.severity)
-    elseif opts.severity_limit then
-      opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
-    end
+  opts = opts or {}
+  opts.where = "cursor"
+  opts.pos = position
+  if opts.severity then
+    opts.severity = severity_lsp_to_vim(opts.severity)
+  elseif opts.severity_limit then
+    opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
   end
-  return vim.diagnostic.show_position_diagnostics(opts, buf_nr, position)
+  return vim.diagnostic.open_float(buf_nr, opts)
 end
 
 --- Open a floating window with the diagnostics from {line_nr}
@@ -573,11 +574,13 @@ end
 ---@param client_id number|nil the client id
 ---@return table {popup_bufnr, win_id}
 function M.show_line_diagnostics(opts, buf_nr, line_nr, client_id)
+  opts = opts or {}
+  opts.where = "line"
+  opts.pos = line_nr
   if client_id then
-    opts = opts or {}
     opts.namespace = M.get_namespace(client_id)
   end
-  return vim.diagnostic.show_line_diagnostics(opts, buf_nr, line_nr)
+  return vim.diagnostic.open_float(buf_nr, opts)
 end
 
 --- Redraw diagnostics for the given buffer and client