Temporary files are not cleaned up

[per1234]

Describe the problem

Arduino Language Server and clangd create some temporary files:

• ~Name format: arduino-language-server2131811926/~
  • ~Arduino CLI sketch build folder~ (Solved by #146)
• Name format: system-includes-0f3fe3.clangd
  • Created by clangd
• Name format: preamble-4df37f.pch
  • Created by clangd

The first two of these persist even after the user exits the IDE.

The files accumulate over time, consuming significant amounts of disk space and may eventually cause a performance impact.

To reproduce

1. Take note of the contents of your temporary folder.
   • Windows:

     C:\Users\<user name>\AppData\Local\Temp

   • Linux:

     /tmp

   • macOS

     $TMPDIR

2. Start Arduino IDE 2.x.
3. Select Tools > Board > Arduino AVR Boards > Arduino Uno from the Arduino IDE menus. ⓘ This is only an arbitrary choice of a board that is supported by the language server.
4. Wait for the "Building sketch" and/or "indexing ..." operations indicated on the left side of the Arduino IDE status bar to finish.
5. Select File > Quit from the Arduino IDE menus.
6. Examine the contents of your temporary folder.

🐛 Multiple additional arduino-language-servernnnnnnnnn folders are present. 🐛 (If using Windows) Multiple additional system-includes-nnnnn.clangd files are present. 🐛 The files produced by this single minimal demo consume a significant amount of disk space (on the order of > 0.5 MB on Windows).

Expected behavior

Temporary files are cleaned up on exit.

Arduino Language Server version

bdef5c27830b1d4a33908068ed87514757874052

Operating system

• Windows
• Linux
• macOS

Operating system version

• Windows 11
• Ubuntu 22.04
• macOS Ventura

Additional context

I don't see the system-includes-nnnnn.clangd files in the temporary folder on Linux and macOS even while the IDE is running, so I am not sure whether they are never created at all, or whether they are stored in some other location.

---

Additional reports:

• https://forum.arduino.cc/t/cleanup-of-tmp-seems-inop-kubuntu-20-04/1072075
• https://forum.arduino.cc/t/windows-10-ide-2-0-2-slow-start/1061136/4
• https://forum.arduino.cc/t/rc9-2-temporary-directories/1022812
• https://forum.arduino.cc/t/temporary-files-from-the-arduino-ide/1067309

---

Related:

• https://github.com/arduino/arduino-ide/issues/1779

Issue checklist

• [X] I searched for previous reports in the issue tracker
• [X] I verified the problem still occurs when using the latest version
• [X] My report contains all necessary details

[cmaglie]

Reopening to investigate clangd-related temp files.

[umbynos]

@per1234 could you please test if this can be reproduced with #154 we are not able to reproduce this