From f93360d85490020bd30a0085e727a06b32e31c86 Mon Sep 17 00:00:00 2001
From: "Kenneth Benzie (Benie)" <benie@infektor.net>
Date: Thu, 14 Mar 2024 21:13:28 +0000
Subject: [PATCH] Actually run compdb asynchronously

Turns out vim.schedule() only defers calling the function until main
event loop has some free cycles but can still block the UI, just a bit
later. This patch replaces the external command invoked in the callback
passed into vim.schedule() with vim.fn.jobstart() and moves the other
code into job callbacks.
---
 lua/build.lua | 62 +++++++++++++++++++++++++--------------------------
 1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/lua/build.lua b/lua/build.lua
index 134c8a4..5565395 100644
--- a/lua/build.lua
+++ b/lua/build.lua
@@ -19,44 +19,44 @@ function build.set_dir(dirname)
     echo('directory does not exist: ' .. build_dir, 'Error')
     return
   end
-  if vim.fn.filereadable(build_dir .. '/compile_commands.json') == 0 then
-    echo('compile_commands.json not found in: ' .. build_dir, 'Error')
-    return
-  end
 
   build.dir = build_dir
 
-  -- Invoke async function to avoid blocking the UI
-  vim.schedule(function()
-    echo('Processing compile_commands.json with compdb ...', 'DiagnosticInfo')
+  echo('Processing compile_commands.json with compdb ...', 'DiagnosticInfo')
+  local compile_commands = current_dir .. '/compile_commands.json'
+  -- Post-process compile_commands.json with compdb as an async job to avoid
+  -- blocking the user interface
+  vim.fn.jobstart(
+    'compdb -p ' .. build.dir .. ' list > ' .. compile_commands, {
 
-    -- Post-process compile_commands.json with compdb
-    local compile_commands = current_dir .. '/compile_commands.json'
-    local output = vim.fn.systemlist(
-      'compdb -p ' .. build.dir .. ' list > ' .. compile_commands)
+      -- Restart clangd language server
+      -- TODO: Configure cmake language server?
+      on_exit = function()
+        vim.cmd [[ LspRestart clangd ]]
+        echo('Build directory selected: ' .. dirname, 'DiagnosticInfo')
+      end,
 
-    -- Remove any lines containing a compdb warning
-    local error = {}
-    local warning = 'WARNING:compdb'
-    for _, line in ipairs(output) do
-      if string.sub(line, 1, #warning) ~= warning then
-        table.insert(error, line)
-      end
-    end
+      -- Display any error messages to the user
+      on_stderr = function(_, output, _)
+        -- Remove any lines containing a compdb warning
+        local error = {}
+        local warning = 'WARNING:compdb'
+        for _, line in ipairs(output) do
+          if string.sub(line, 1, #warning) ~= warning then
+            table.insert(error, line)
+          end
+        end
 
-    -- Display the error message if there was one
-    if table.maxn(error) > 0 then
-      echo(vim.fn.join(error, '\n'), 'Error')
-      return
-    end
+        -- Display the error message if there was one
+        if table.maxn(error) > 0 then
+          echo(vim.fn.join(error, '\n'), 'Error')
+          return
+        end
+      end,
 
-    -- TODO: Configure cmake language server?
-
-    -- Restart clangd language server
-    vim.cmd [[ LspRestart clangd ]]
-
-    echo('Build directory selected: ' .. dirname, 'DiagnosticInfo')
-  end)
+      stderr_buffered = true,
+    }
+  )
 end
 
 function build.select_dir(callback)