feat(diagnostic): jump to related info location from open_float #34837

This commit allows users to jump to the location specified in a
diagnostic's `relatedInformation`, using `gf` from within the
`open_float` window. The cursor need only be on line that displays the
related info.

runtime/doc/lsp.txt

@@ -1903,7 +1903,8 @@ Lua module: vim.lsp.diagnostic                                *lsp-diagnostic*
 This module provides functionality for requesting LSP diagnostics for a
 document/workspace and populating them using |vim.Diagnostic|s.
 `DiagnosticRelatedInformation` is supported: it is included in the window
-shown by |vim.diagnostic.open_float()|.
+shown by |vim.diagnostic.open_float()|. When the cursor is on a line with
+related information, |gf| jumps to the problem location.
 
 
 from({diagnostics})                                *vim.lsp.diagnostic.from()*

runtime/doc/news.txt

@@ -204,6 +204,9 @@ LSP
 • LSP `DiagnosticRelatedInformation` is now shown in
   |vim.diagnostic.open_float()|. It is read from the LSP diagnostic object
   stored in the `user_data` field.
+• When inside the float created by |vim.diagnostic.open_float()| and the
+  cursor is on a line with `DiagnosticRelatedInformation`, |gf| can be used to
+  jump to the problematic location.
 
 LUA
 

runtime/lua/vim/diagnostic.lua

@@ -2341,6 +2341,8 @@ function M.open_float(opts, ...)
     end
   end
 
+  ---@type table<integer, lsp.Location>
+  local related_info_locations = {}
   for i, diagnostic in ipairs(diagnostics) do
     if type(prefix_opt) == 'function' then
       --- @cast prefix_opt fun(...): string?, string?
@@ -2378,15 +2380,16 @@ function M.open_float(opts, ...)
     -- Below the diagnostic, show its LSP related information (if any) in the form of file name and
     -- range, plus description.
     for _, info in ipairs(related_info) do
-      -- TODO: Somehow allow users to open the location when their cursor is over it?
-      local file_name = vim.fs.basename(vim.uri_to_fname(info.location.uri))
+      local location = info.location
+      local file_name = vim.fs.basename(vim.uri_to_fname(location.uri))
       local info_suffix = ': ' .. info.message
+      related_info_locations[#lines + 1] = info.location
       lines[#lines + 1] = string.format(
         '%s%s:%s:%s%s',
         default_pre,
         file_name,
-        info.location.range.start.line,
-        info.location.range.start.character,
+        location.range.start.line,
+        location.range.start.character,
         info_suffix
       )
       highlights[#highlights + 1] = {
@@ -2412,6 +2415,19 @@ function M.open_float(opts, ...)
   local float_bufnr, winnr = vim.lsp.util.open_floating_preview(lines, 'plaintext', opts)
   vim.bo[float_bufnr].path = vim.bo[bufnr].path
 
+  -- TODO: Handle this generally (like vim.ui.open()), rather than overriding gf.
+  vim.keymap.set('n', 'gf', function()
+    local cursor_row = api.nvim_win_get_cursor(0)[1]
+    local location = related_info_locations[cursor_row]
+    if location then
+      -- Split the window before calling `show_document` so the window doesn't disappear.
+      vim.cmd.split()
+      vim.lsp.util.show_document(location, 'utf-16', { focus = true })
+    else
+      vim.cmd.normal({ 'gf', bang = true })
+    end
+  end, { buffer = float_bufnr, remap = false })
+
   --- @diagnostic disable-next-line: deprecated
   local add_highlight = api.nvim_buf_add_highlight
 

runtime/lua/vim/lsp/diagnostic.lua

@@ -1,6 +1,7 @@
 ---@brief This module provides functionality for requesting LSP diagnostics for a document/workspace
 ---and populating them using |vim.Diagnostic|s. `DiagnosticRelatedInformation` is supported: it is
----included in the window shown by |vim.diagnostic.open_float()|.
+---included in the window shown by |vim.diagnostic.open_float()|. When the cursor is on a line with
+---related information, |gf| jumps to the problem location.
 
 local lsp = vim.lsp
 local protocol = lsp.protocol

test/functional/lua/diagnostic_spec.lua

@@ -3383,6 +3383,92 @@ describe('vim.diagnostic', function()
       )
     end)
 
+    it('can add LSP related information to a diagnostic', function()
+      local related_info_uri = 'file:///fake/uri'
+
+      -- Populate the related info buffer.
+      exec_lua(function()
+        local fake_bufnr = vim.uri_to_bufnr(related_info_uri)
+        vim.fn.bufload(fake_bufnr)
+        vim.api.nvim_buf_set_lines(fake_bufnr, 0, 1, false, {
+          'O, the Pelican,',
+          'so smoothly doth he crest.',
+          'a wind god!',
+        })
+        vim.api.nvim_win_set_buf(0, fake_bufnr)
+      end)
+
+      -- Displays related info.
+      eq(
+        {
+          '1. Some warning',
+          '   uri:1:0: Some extra info',
+          '   uri:2:3: Some more extra info',
+        },
+        exec_lua(function()
+          ---@type vim.Diagnostic
+          local diagnostic = _G.make_warning('Some warning', 1, 1, 1, 3)
+          diagnostic.user_data = {
+            -- Related information comes from LSP user_data
+            lsp = {
+              relatedInformation = {
+                {
+                  message = 'Some extra info',
+                  location = {
+                    uri = related_info_uri,
+                    range = {
+                      start = {
+                        line = 1,
+                        character = 0,
+                      },
+                      ['end'] = {
+                        line = 1,
+                        character = 1,
+                      },
+                    },
+                  },
+                },
+                {
+                  message = 'Some more extra info',
+                  location = {
+                    uri = related_info_uri,
+                    range = {
+                      start = {
+                        line = 2,
+                        character = 3,
+                      },
+                      ['end'] = {
+                        line = 4,
+                        character = 5,
+                      },
+                    },
+                  },
+                },
+              },
+            },
+          }
+          vim.api.nvim_win_set_buf(0, _G.diagnostic_bufnr)
+          vim.diagnostic.set(_G.diagnostic_ns, _G.diagnostic_bufnr, { diagnostic })
+          local float_bufnr, winnr = vim.diagnostic.open_float({ header = false, scope = 'buffer' })
+          local lines = vim.api.nvim_buf_get_lines(float_bufnr, 0, -1, false)
+          -- Put the cursor on a line with related info
+          vim.api.nvim_tabpage_set_win(0, winnr)
+          vim.api.nvim_win_set_cursor(0, { 2, 0 })
+          return lines
+        end)
+      )
+
+      -- Jumps to related info.
+      eq(
+        'so smoothly doth he crest.',
+        exec_lua(function()
+          vim.cmd.norm('gf')
+          vim.wait(20, function() end)
+          return vim.api.nvim_get_current_line()
+        end)
+      )
+    end)
+
     it('works with the old signature', function()
       eq(
         { '1. Syntax error' },