refactor: native sessions view

We no longer rely on nvim-dap's builtin sessions widget, we rolled our
own. Having full control of the rendering is nice, as it allows changing
stuff more easily on the future.

Kinda related to #124: there's an ongoing effort to also get rid of the
scopes widget. With that, nvim-dap-view would be completely independent
from the widgets, which I think is nice?

Having a single view based on widgets sucks, because it introduces some
abstractions and yada yada yada. It's simple enough to be implemented
"natively" with too much effort

Author: igorlfs

README.md

@@ -27,6 +27,7 @@ return {
 - Watch expressions
 - Manipulate breakpoints
 - Navigate in the call stack
+- Manage ongoing debug sessions
 - Inspect all variables in scope[^1]
 - REPL
 

docs/src/routes/home/+page.md

@@ -82,7 +82,9 @@ Use the scopes widget provided by nvim-dap
 
 <img src="https://i.ibb.co/1fSHs7J1/image.png" alt="sessions view">
 
-Use the sessions widget provided by nvim-dap (**disabled by default**)
+List all debugging sessions (**disabled by default**)
+
+- Switch to a session
 
 ### REPL view
 

lua/dap-view/listeners.lua

@@ -3,15 +3,13 @@ local dap = require("dap")
 local state = require("dap-view.state")
 local breakpoints = require("dap-view.breakpoints.view")
 local scopes = require("dap-view.scopes.view")
-local sessions = require("dap-view.sessions.view")
 local util = require("dap-view.util")
 local term = require("dap-view.console.view")
 local setup = require("dap-view.setup")
 local refresher = require("dap-view.refresher")
 local winbar = require("dap-view.options.winbar")
 local traversal = require("dap-view.tree.traversal")
 local scroll = require("dap-view.console.scroll")
-local adapter_ = require("dap-view.util.adapter")
 
 local SUBSCRIPTION_ID = "dap-view"
 
@@ -41,7 +39,7 @@ dap.listeners.on_session[SUBSCRIPTION_ID] = function(_, new)
             if util.is_buf_valid(new.term_buf) and scroll.is_autoscrolling(new.term_buf) then
                 local winnr = vim.tbl_contains(setup.config.winbar.sections, "console") and state.winnr
                     or state.term_winnr
-                if util.is_win_valid(winnr) then
+                if util.is_win_valid(winnr) and state.current_section == "console" then
                     ---@cast winnr integer
                     scroll.scroll_to_bottom(winnr, new.term_buf)
                 end
@@ -53,6 +51,15 @@ dap.listeners.on_session[SUBSCRIPTION_ID] = function(_, new)
     else
         state.current_session_id = nil
         state.current_adapter = nil
+
+        -- Forces a refresh when terminating the last session
+        -- Schedule so the session can properly finish (workaroundy)
+        --
+        -- This is useful when terminating sessions from the js-debug-adapter
+        -- Setup: any attach configuration, when terminating either the root or any child
+        -- (more consistent when terminating a child)
+        -- View: sessions
+        vim.schedule(refresher.refresh_session_based_views)
     end
 end
 
@@ -100,12 +107,14 @@ dap.listeners.after.setBreakpoints[SUBSCRIPTION_ID] = function()
 end
 
 dap.listeners.after.scopes[SUBSCRIPTION_ID] = function(session)
+    if state.current_section == "sessions" then
+        require("dap-view.views").switch_to_view("sessions")
+    end
+
     -- nvim-dap needs a buffer to operate
     if util.is_buf_valid(state.bufnr) then
         if state.current_section == "scopes" then
             scopes.refresh()
-        elseif state.current_section == "sessions" then
-            sessions.refresh()
         end
     end
     if state.current_section == "threads" then
@@ -176,14 +185,7 @@ end
 
 -- The debuggee has terminated
 dap.listeners.after.event_terminated[SUBSCRIPTION_ID] = function(session)
-    -- When terminating, outdated sessions may be shown
-    -- As a workaround, do not refresh for the root session from js-debug-adapter
-    -- Steps: js-debug-adapter (chrome) + attach
-    local is_js_adapter = adapter_.is_js_adapter(session.config.type)
-
-    if not is_js_adapter or session.parent then
-        refresher.refresh_session_based_views()
-    end
+    refresher.refresh_session_based_views()
 
     winbar.redraw_controls()
 

lua/dap-view/refresher.lua

@@ -1,7 +1,6 @@
 local state = require("dap-view.state")
 local threads = require("dap-view.threads.view")
 local scopes = require("dap-view.scopes.view")
-local sessions = require("dap-view.sessions.view")
 local exceptions = require("dap-view.exceptions.view")
 local eval = require("dap-view.watches.eval")
 local util = require("dap-view.util")
@@ -21,13 +20,13 @@ M.refresh_session_based_views = function()
         exceptions.show()
     elseif state.current_section == "watches" then
         require("dap-view.views").switch_to_view("watches")
+    elseif state.current_section == "sessions" then
+        require("dap-view.views").switch_to_view("sessions")
     end
 
     if util.is_buf_valid(state.bufnr) then
         if state.current_section == "scopes" then
             scopes.refresh()
-        elseif state.current_section == "sessions" then
-            sessions.refresh()
         end
     end
 end

lua/dap-view/sessions/actions.lua

@@ -0,0 +1,19 @@
+local dap = require("dap")
+
+local state = require("dap-view.state")
+
+local M = {}
+
+---@param line integer
+M.switch_to_session = function(line)
+    local session = state.sessions_by_line[line]
+
+    if session == nil then
+        vim.notify("No session under the cursor")
+        return
+    end
+
+    dap.set_session(session)
+end
+
+return M

lua/dap-view/sessions/view.lua

@@ -1,41 +1,63 @@
 local dap = require("dap")
-local dap_widgets = require("dap.ui.widgets")
 
 local views = require("dap-view.views")
-local winbar = require("dap-view.options.winbar")
 local state = require("dap-view.state")
 local util = require("dap-view.util")
-local widgets = require("dap-view.util.widgets")
+local hl = require("dap-view.util.hl")
 
 local M = {}
 
-local sessions_widget
+local api = vim.api
 
-local last_sessions_bufnr
+---@param children table<number,dap.Session>
+---@param focused_id number
+---@param line number
+local function show_children_sessions(children, focused_id, line)
+    for _, session in pairs(children) do
+        local content = session.id .. ": " .. session.config.name
 
-local launch_and_refresh_widget = function()
-    if last_sessions_bufnr == nil or last_sessions_bufnr ~= state.bufnr then
-        sessions_widget = widgets.new_widget(state.bufnr, state.winnr, dap_widgets.sessions)
-        last_sessions_bufnr = state.bufnr
+        local parent = session.parent
+        local num_parents = 0
+        while parent ~= nil do
+            parent = parent.parent
+            num_parents = num_parents + 1
+        end
 
-        sessions_widget.open()
-    end
+        local prefix = string.rep("  ", num_parents)
+        local indented_content = prefix .. content
 
-    if not util.is_win_valid(state.winnr) then
-        return
-    end
+        api.nvim_buf_set_lines(state.bufnr, line, line, true, { indented_content })
+
+        if focused_id == session.id then
+            hl.hl_range("FrameCurrent", { line, 0 }, { line, -1 })
+        end
 
-    sessions_widget.refresh()
+        state.sessions_by_line[line + 1] = session
+
+        line = line + 1
+
+        line = show_children_sessions(session.children, focused_id, line)
+    end
 
-    views.cleanup_view(not dap.session(), "No active session")
+    return line
 end
 
 M.show = function()
-    winbar.refresh_winbar("sessions")
+    if util.is_buf_valid(state.bufnr) and util.is_win_valid(state.winnr) then
+        local focused = dap.session()
 
-    launch_and_refresh_widget()
-end
+        if views.cleanup_view(focused == nil, "No active session") then
+            return
+        end
+
+        ---@cast focused dap.Session
+
+        local line = 0
 
-M.refresh = launch_and_refresh_widget
+        line = show_children_sessions(dap.sessions(), focused.id, line)
+
+        api.nvim_buf_set_lines(state.bufnr, line, -1, true, {})
+    end
+end
 
 return M

lua/dap-view/state.lua

@@ -35,6 +35,7 @@
 ---@field frames_by_line table<integer, dap.StackFrame>
 ---@field expression_views_by_line table<integer, {expression: string, view: dapview.ExpressionView}>
 ---@field variable_views_by_line table<integer, {parent_reference: number, variable: dap.Variable, view: dapview.VariableView}>
+---@field sessions_by_line table<integer, dap.Session>
 ---@field watched_expressions table<string, dapview.ExpressionView>
 ---@field expr_count integer
 ---@field cur_pos table<dapview.DefaultSection,integer?>
@@ -47,6 +48,7 @@ local M = {
     frames_by_line = {},
     expression_views_by_line = {},
     variable_views_by_line = {},
+    sessions_by_line = {},
     subtle_frames = false,
     watched_expressions = {},
     cur_pos = {},

lua/dap-view/views/keymaps/views.lua

@@ -16,6 +16,8 @@ M.views_keymaps = function()
             require("dap-view.views.util").jump_to_location("^(.-)|(%d+)|")
         elseif state.current_section == "threads" then
             require("dap-view.threads.actions").jump_and_set_frame(cursor_line)
+        elseif state.current_section == "sessions" then
+            require("dap-view.sessions.actions").switch_to_session(cursor_line)
         elseif state.current_section == "exceptions" then
             require("dap-view.exceptions.actions").toggle_exception_filter()
         elseif state.current_section == "scopes" or state.current_section == "sessions" then
@@ -29,12 +31,6 @@ M.views_keymaps = function()
                 end
             end)()
         end
-
-        -- Selecting a session triggers a full redraw
-        -- To properly restore the cursor position we have to call switch_to_view
-        if state.current_section == "sessions" then
-            require("dap-view.views").switch_to_view("sessions")
-        end
     end)
 
     keymap("<C-w><CR>", function()