feat: add support for multi-range diagnostics with selection-aware filtering

- Enhance diagnostics to handle multiple selection ranges simultaneously
- Add visual filter indicator in context bar for scoped diagnostic display
- Improve chat context to automatically use stored selections for diagnostic filtering

Author: sudo-tee

lua/opencode/context/base_context.lua

@@ -1,6 +1,3 @@
--- Base context utilities
--- Static methods for gathering context data from the editor
-
 local util = require('opencode.util')
 local config = require('opencode.config')
 local state = require('opencode.state')
@@ -41,7 +38,7 @@ end
 
 ---@param buf integer
 ---@param context_config? OpencodeContextConfig
----@param range? { start_line: integer, end_line: integer }
+---@param range? { start_line: integer, end_line: integer } | { start_line: integer, end_line: integer }[]
 ---@return OpencodeDiagnostic[]|nil
 function M.get_diagnostics(buf, context_config, range)
   if not M.is_context_enabled('diagnostics', context_config) then
@@ -69,16 +66,27 @@ function M.get_diagnostics(buf, context_config, range)
   end
 
   local diagnostics = {}
+
+  local ranges = nil
+  if range then
+    if range[1] and type(range[1]) == 'table' then
+      ranges = range
+    else
+      ranges = { range }
+    end
+  end
+
   if diagnostic_conf.only_closest then
-    if range then
-      -- Get diagnostics for the specified range
-      for line_num = range.start_line, range.end_line do
-        local line_diagnostics = vim.diagnostic.get(buf, {
-          lnum = line_num,
-          severity = severity_levels,
-        })
-        for _, diag in ipairs(line_diagnostics) do
-          table.insert(diagnostics, diag)
+    if ranges then
+      for _, r in ipairs(ranges) do
+        for line_num = r.start_line, r.end_line do
+          local line_diagnostics = vim.diagnostic.get(buf, {
+            lnum = line_num,
+            severity = severity_levels,
+          })
+          for _, diag in ipairs(line_diagnostics) do
+            table.insert(diagnostics, diag)
+          end
         end
       end
     else
@@ -92,17 +100,7 @@ function M.get_diagnostics(buf, context_config, range)
       diagnostics = line_diagnostics
     end
   else
-    -- Get all diagnostics, optionally filtered by range
     diagnostics = vim.diagnostic.get(buf, { severity = severity_levels })
-    if range then
-      local filtered_diagnostics = {}
-      for _, diag in ipairs(diagnostics) do
-        if diag.lnum >= range.start_line and diag.lnum <= range.end_line then
-          table.insert(filtered_diagnostics, diag)
-        end
-      end
-      diagnostics = filtered_diagnostics
-    end
   end
 
   if #diagnostics == 0 then
@@ -124,7 +122,7 @@ function M.get_diagnostics(buf, context_config, range)
     })
   end
 
-  return opencode_diagnostics
+  return opencode_diagnostics, ranges
 end
 
 ---@param buf integer

lua/opencode/context/chat_context.lua

@@ -283,6 +283,54 @@ function M.get_mentioned_subagents()
   return M.context.mentioned_subagents or {}
 end
 
+-- Chat-context-aware get_diagnostics that considers stored selections
+---@param buf integer
+---@param context_config? OpencodeContextConfig
+---@param range? { start_line: integer, end_line: integer }
+---@return OpencodeDiagnostic[]|nil
+function M.get_diagnostics(buf, context_config, range)
+  -- Use explicit range if provided
+  if range then
+    return base_context.get_diagnostics(buf, context_config, range)
+  end
+
+  if M.context.selections and #M.context.selections > 0 then
+    local selection_ranges = {}
+
+    for _, sel in ipairs(M.context.selections) do
+      if sel.lines then
+        -- Handle both formats: "1, 5" and "1-5"
+        local start_line, end_line = sel.lines:match('(%d+)[,%-]%s*(%d+)')
+        if not start_line then
+          -- Single line case like "5, 5" or just "5"
+          start_line = sel.lines:match('(%d+)')
+          end_line = start_line
+        end
+
+        if start_line then
+          local start_num = tonumber(start_line)
+          local end_num = tonumber(end_line)
+
+          if start_num and end_num then
+            -- Convert to 0-based
+            local selection_range = {
+              start_line = start_num - 1,
+              end_line = end_num - 1,
+            }
+            table.insert(selection_ranges, selection_range)
+          end
+        end
+      end
+    end
+
+    if #selection_ranges > 0 then
+      return base_context.get_diagnostics(buf, context_config, selection_ranges)
+    end
+  end
+
+  return base_context.get_diagnostics(buf, context_config, nil)
+end
+
 ---@param current_file table|nil
 ---@return boolean, boolean -- should_update, is_different_file
 function M.should_update_current_file(current_file)
@@ -299,6 +347,7 @@ function M.should_update_current_file(current_file)
     return true, true
   end
 
+  -- Same file, check modification time
   local file_path = current_file.path
   if not file_path or vim.fn.filereadable(file_path) ~= 1 then
     return false, false
@@ -341,7 +390,7 @@ function M.load()
   end
 
   M.context.cursor_data = cursor_data
-  M.context.linter_errors = base_context.get_diagnostics(buf, nil, nil)
+  M.context.linter_errors = M.get_diagnostics(buf, nil, nil)
 
   -- Handle current selection
   local current_selection = base_context.get_current_selection()
@@ -483,7 +532,7 @@ M.format_message = Promise.async(function(prompt, opts)
   if range then
     diag_range = { start_line = math.floor(range.start) - 1, end_line = math.floor(range.stop) - 1 }
   end
-  local diagnostics = base_context.get_diagnostics(buf, context_config, diag_range)
+  local diagnostics = M.get_diagnostics(buf, context_config, diag_range)
   if diagnostics and #diagnostics > 0 then
     table.insert(parts, format_diagnostics_part(diagnostics, diag_range))
   end

lua/opencode/ui/context_bar.lua

@@ -3,6 +3,7 @@ local M = {}
 local context = require('opencode.context')
 local icons = require('opencode.ui.icons')
 local state = require('opencode.state')
+local config = require('opencode.config')
 local prompt_guard_indicator = require('opencode.ui.prompt_guard_indicator')
 
 local function get_current_file_info(ctx)
@@ -111,18 +112,18 @@ local function create_winbar_segments()
       counts[type_name] = (counts[type_name] or 0) + 1
     end
 
+    local filter_icon = config.context.diagnostics.only_closest and icons.get('filter') or ''
     for _, type_name in pairs(severity_types) do
       local count = counts[type_name]
       if count and count > 0 then
         table.insert(segments, {
           icon = icons.get(type_name),
-          text = '(' .. count .. ')',
+          text = '(' .. count .. filter_icon .. ')',
           highlight = 'OpencodeContext' .. type_name:gsub('^%l', string.upper),
         })
       end
     end
   end
-
   return segments
 end
 

lua/opencode/ui/icons.lua

@@ -38,6 +38,7 @@ local presets = {
     error = ' ',
     warning = ' ',
     info = ' ',
+    filter = '/',
     selection = '󰫙 ',
     command = ' ',
   },
@@ -74,6 +75,7 @@ local presets = {
     error = '[E]',
     warning = '[W]',
     info = '[I] ',
+    filter = '/*',
     selection = "'<'> ",
     command = '::',
   },

tests/unit/context_bar_spec.lua

@@ -2,6 +2,7 @@ local context_bar = require('opencode.ui.context_bar')
 local context = require('opencode.context')
 local state = require('opencode.state')
 local icons = require('opencode.ui.icons')
+local config = require('opencode.config')
 local assert = require('luassert')
 
 describe('opencode.ui.context_bar', function()
@@ -181,7 +182,9 @@ describe('opencode.ui.context_bar', function()
       assert.is_not_nil(winbar_capture.value:find('L:10')) -- Cursor data
     end)
 
-    it('renders winbar with diagnostics', function()
+    it('renders winbar with all diagnostics', function()
+      local original_only_closest = config.context.diagnostics.only_closest
+      config.context.diagnostics.only_closest = false
       mock_context.linter_errors = {
         { severity = 1 }, -- ERROR
         { severity = 1 }, -- ERROR
@@ -199,6 +202,30 @@ describe('opencode.ui.context_bar', function()
       assert.is_not_nil(winbar_capture.value:find(icons.get('error') .. '%(2%)')) -- 2 errors
       assert.is_not_nil(winbar_capture.value:find(icons.get('warning') .. '%(1%)')) -- Warning icon
       assert.is_not_nil(winbar_capture.value:find(icons.get('info') .. '%(1%)')) -- Info icon
+      config.context.diagnostics.only_closest = original_only_closest
+    end)
+
+    it('renders winbar with filtered diagnostics', function()
+      local original_only_closest = config.context.diagnostics.only_closest
+      config.context.diagnostics.only_closest = true
+      mock_context.linter_errors = {
+        { severity = 1 }, -- ERROR
+        { severity = 1 }, -- ERROR
+        { severity = 2 }, -- WARN
+        { severity = 3 }, -- INFO
+      }
+
+      local mock_input_win = 2004
+      local winbar_capture = create_mock_window(mock_input_win)
+
+      state.windows = { input_win = mock_input_win }
+      context_bar.render()
+
+      assert.is_string(winbar_capture.value)
+      assert.is_not_nil(winbar_capture.value:find(icons.get('error') .. '%(2' .. icons.get('filter') .. '%)')) -- 2 errors
+      assert.is_not_nil(winbar_capture.value:find(icons.get('warning') .. '%(1' .. icons.get('filter') .. '%)')) -- Warning icon
+      assert.is_not_nil(winbar_capture.value:find(icons.get('info') .. '%(1' .. icons.get('filter') .. '%)')) -- Info icon
+      config.context.diagnostics.only_closest = original_only_closest
     end)
 
     it('respects context enabled settings', function()