feat: :RustLsp renderDiagnostic command + open in split actions (#146)

CHANGELOG.md

@@ -6,6 +6,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [3.14.0] - 2024-01-10
+
+### Added
+
+- `:RustLsp renderDiagnostic` command:
+  Render diagnostics as displayed during `cargo build`.
+- Add `Open in split` action to `explainError` and `renderDiagnostic`
+  float preview windows.
+
 ## [3.13.1] - 2024-01-10
 
 ### Fixed

README.md

@@ -282,6 +282,28 @@ for more configuration options.
 
 </details>
 
+<details>
+  <summary>
+	<b>Render diagnostics</b>
+  </summary>
+
+  Display a hover window with the rendered diagnostic, as displayed
+  during `cargo build`.
+  Useful for solving bugs around borrowing and generics,
+  as it consolidates the important bits (sometimes across files)
+  together.
+
+  ```vimscript
+  :RustLsp renderDiagnostic
+  ```
+  ```lua
+  vim.cmd.RustLsp('renderDiagnostic')
+  ```
+
+![](https://github.com/mrcjkb/rustaceanvim/assets/12857160/a972c6b6-c504-4c2a-8380-53451bb8c2de)
+
+</details>
+
 <details>
   <summary>
 	<b>Open Cargo.toml</b>

doc/rustaceanvim.txt

@@ -29,6 +29,9 @@ It accepts the following subcommands:
  `expandMacro` - Expand macros recursively.
  `moveItem [up|down]` - Move items up or down.
  `hover [action|range]` - Hover actions, or hover over visually selected range.
+ `explainError` - Display a hover window with explanations form the Rust error index.
+ `renderDiagnostic` - Display a hover window with the rendered diagnostic,
+                      as displayed during `cargo build`.
  `openCargo` - Open the Cargo.toml file for the current package.
  `parentModule` - Open the current module's parent module.
  `joinLines` - Join adjacent lines.

lua/rustaceanvim/commands/diagnostic.lua

@@ -0,0 +1,215 @@
+local M = {}
+
+local config = require('rustaceanvim.config.internal')
+local compat = require('rustaceanvim.compat')
+local ui = require('rustaceanvim.ui')
+
+local rustc = 'rustc'
+
+---@class DiagnosticWindowState
+local _window_state = {
+  ---@type integer | nil
+  float_winnr = nil,
+  ---@type integer | nil
+  latest_scratch_buf_id = nil,
+}
+
+---@param bufnr integer
+---@param winnr integer
+---@param lines string[]
+local function set_open_split_keymap(bufnr, winnr, lines)
+  local function open_split()
+    -- check if a buffer with the latest id is already open, if it is then
+    -- delete it and continue
+    ui.delete_buf(_window_state.latest_scratch_buf_id)
+
+    -- create a new buffer
+    _window_state.latest_scratch_buf_id = vim.api.nvim_create_buf(false, true) -- not listed and scratch
+
+    -- split the window to create a new buffer and set it to our window
+    ui.split(false, _window_state.latest_scratch_buf_id)
+
+    -- set filetype to rust for syntax highlighting
+    vim.bo[_window_state.latest_scratch_buf_id].filetype = 'rust'
+    -- write the expansion content to the buffer
+    vim.api.nvim_buf_set_lines(_window_state.latest_scratch_buf_id, 0, 0, false, lines)
+  end
+  vim.keymap.set('n', '<CR>', function()
+    local line = vim.api.nvim_win_get_cursor(winnr)[1]
+    if line > 1 then
+      return
+    end
+    open_split()
+  end, { buffer = bufnr, noremap = true, silent = true })
+end
+
+---@return nil
+local function close_hover()
+  local winnr = _window_state.float_winnr
+  if winnr ~= nil and vim.api.nvim_win_is_valid(winnr) then
+    vim.api.nvim_win_close(winnr, true)
+    _window_state.float_winnr = nil
+  end
+end
+
+---@param bufnr integer
+local function set_close_keymaps(bufnr)
+  vim.keymap.set('n', 'q', close_hover, { buffer = bufnr, noremap = true, silent = true })
+  vim.keymap.set('n', '<Esc>', close_hover, { buffer = bufnr, noremap = true, silent = true })
+end
+
+function M.explain_error()
+  if vim.fn.executable(rustc) ~= 1 then
+    vim.notify('rustc is needed to explain errors.', vim.log.levels.ERROR)
+    return
+  end
+
+  local diagnostics = vim.tbl_filter(function(diagnostic)
+    return diagnostic.code ~= nil
+      and diagnostic.source == 'rustc'
+      and diagnostic.severity == vim.diagnostic.severity.ERROR
+  end, vim.diagnostic.get(0, {}))
+  if #diagnostics == 0 then
+    vim.notify('No explainnable errors found.', vim.log.levels.INFO)
+    return
+  end
+  local win_id = vim.api.nvim_get_current_win()
+  local opts = {
+    cursor_position = vim.api.nvim_win_get_cursor(win_id),
+    severity = vim.diagnostic.severity.ERROR,
+    wrap = true,
+  }
+  local found = false
+  local diagnostic
+  local pos_map = {}
+  local pos_id = 1
+  repeat
+    diagnostic = vim.diagnostic.get_next(opts)
+    pos_map[pos_id] = diagnostic
+    if diagnostic == nil then
+      break
+    end
+    found = diagnostic.code ~= nil and diagnostic.source == 'rustc'
+    local pos = { diagnostic.lnum, diagnostic.col }
+    pos_id = pos[1] + pos[2]
+    opts.cursor_position = pos
+    local searched_all = pos_map[pos_id] ~= nil
+  until diagnostic == nil or found or searched_all
+  if not found then
+    return
+  end
+
+  ---@param sc vim.SystemCompleted
+  local function handler(sc)
+    if sc.code ~= 0 or not sc.stdout then
+      vim.notify('Error calling rustc --explain' .. (sc.stderr and ': ' .. sc.stderr or ''), vim.log.levels.ERROR)
+      return
+    end
+    local output = sc.stdout:gsub('```', '```rust', 1)
+    local markdown_lines = vim.lsp.util.convert_input_to_markdown_lines(output, {})
+    local float_preview_lines = vim.deepcopy(markdown_lines)
+    table.insert(float_preview_lines, 1, '---')
+    table.insert(float_preview_lines, 1, '1. Open in split')
+    vim.schedule(function()
+      close_hover()
+      local bufnr, winnr = vim.lsp.util.open_floating_preview(
+        float_preview_lines,
+        'markdown',
+        vim.tbl_extend('keep', config.tools.float_win_config, {
+          focus = false,
+          focusable = true,
+          focus_id = 'rustc-explain-error',
+          close_events = { 'CursorMoved', 'BufHidden', 'InsertCharPre' },
+        })
+      )
+      _window_state.float_winnr = winnr
+      set_close_keymaps(bufnr)
+      set_open_split_keymap(bufnr, winnr, markdown_lines)
+
+      if config.tools.float_win_config.auto_focus then
+        vim.api.nvim_set_current_win(winnr)
+      end
+    end)
+  end
+
+  -- Save position in the window's jumplist
+  vim.cmd("normal! m'")
+  vim.api.nvim_win_set_cursor(win_id, { diagnostic.lnum + 1, diagnostic.col })
+  -- Open folds under the cursor
+  vim.cmd('normal! zv')
+  compat.system({ rustc, '--explain', diagnostic.code }, nil, vim.schedule_wrap(handler))
+end
+
+---@param diagnostic table
+---@return string | nil
+local function get_rendered_diagnostic(diagnostic)
+  local result = vim.tbl_get(diagnostic, 'user_data', 'lsp', 'data', 'rendered')
+  if type(result) == 'string' then
+    ---@diagnostic disable-next-line: cast-type-mismatch
+    ---@cast result string
+    return result
+  end
+end
+
+function M.render_diagnostic()
+  local diagnostics = vim.tbl_filter(function(diagnostic)
+    return get_rendered_diagnostic(diagnostic) ~= nil
+  end, vim.diagnostic.get(0, {}))
+  if #diagnostics == 0 then
+    vim.notify('No renderable diagnostics found.', vim.log.levels.INFO)
+    return
+  end
+  local win_id = vim.api.nvim_get_current_win()
+  local opts = {
+    cursor_position = vim.api.nvim_win_get_cursor(win_id),
+    wrap = true,
+  }
+  local rendered_diagnostic
+  local diagnostic
+  local pos_map = {}
+  local pos_id = 1
+  repeat
+    diagnostic = vim.diagnostic.get_next(opts)
+    pos_map[pos_id] = diagnostic
+    if diagnostic == nil then
+      break
+    end
+    rendered_diagnostic = get_rendered_diagnostic(diagnostic)
+    local pos = { diagnostic.lnum, diagnostic.col }
+    pos_id = pos[1] + pos[2]
+    opts.cursor_position = pos
+    local searched_all = pos_map[pos_id] ~= nil
+  until diagnostic == nil or rendered_diagnostic ~= nil or searched_all
+  if not rendered_diagnostic then
+    return
+  end
+
+  -- Save position in the window's jumplist
+  vim.cmd("normal! m'")
+  vim.api.nvim_win_set_cursor(win_id, { diagnostic.lnum + 1, diagnostic.col })
+  -- Open folds under the cursor
+  vim.cmd('normal! zv')
+
+  local markdown_lines = vim.lsp.util.convert_input_to_markdown_lines(rendered_diagnostic, {})
+  local float_preview_lines = vim.deepcopy(markdown_lines)
+  table.insert(float_preview_lines, 1, '---')
+  table.insert(float_preview_lines, 1, '1. Open in split')
+  close_hover()
+  local bufnr, winnr = vim.lsp.util.open_floating_preview(
+    float_preview_lines,
+    'markdown',
+    vim.tbl_extend('keep', config.tools.float_win_config, {
+      focus = false,
+      focusable = true,
+      focus_id = 'ra-render-diagnostic',
+      close_events = { 'CursorMoved', 'BufHidden', 'InsertCharPre' },
+    })
+  )
+  _window_state.winnr = winnr
+  set_open_split_keymap(bufnr, winnr, markdown_lines)
+  if config.tools.float_win_config.auto_focus then
+    vim.api.nvim_set_current_win(winnr)
+  end
+end
+
+return M

lua/rustaceanvim/commands/init.lua

@@ -28,7 +28,10 @@ local command_tbl = {
     require('rustaceanvim.commands.expand_macro')()
   end,
   explainError = function(_)
-    require('rustaceanvim.commands.explain_error')()
+    require('rustaceanvim.commands.diagnostic').explain_error()
+  end,
+  renderDiagnostic = function(_)
+    require('rustaceanvim.commands.diagnostic').render_diagnostic()
   end,
   rebuildProcMacros = function()
     require('rustaceanvim.commands.rebuild_proc_macros')()