Unable to generate only the compilation database

[jacquesg]

Bug Report

Current behavior

/home/linuxbrew/.linuxbrew/bin/arduino-cli --config-file /home/jacquesg/.arduino15/arduino-cli.yaml compile --fqbn esp32:esp32:featheresp32 --only-compilation-database --clean --build-path $PWD/build --format json /home/jacquesg/dev/AdvancedWebServer
{                                                                                                                                                                                                         
  "compiler_out": "",                                                                                                                                                                                     
  "compiler_err": "xtensa-esp32-elf-g++: error: /home/jacquesg/dev/AdvancedWebServer/build/build_opt.h: No such file or directory\n",                                                                     
  "builder_result": {                                                                                                                                                                                     
    "build_path": "/home/jacquesg/dev/AdvancedWebServer/build"                                                                                                                                            
  },                                                                                                                                                                                                      
  "success": false                                                                                                                                                                                        
} 

/home/linuxbrew/.linuxbrew/bin/arduino-cli --config-file /home/jacquesg/.arduino15/arduino-cli.yaml compile --fqbn esp32:esp32:featheresp32 --clean --build-path $PWD/build --format json /home/jacquesg/dev/AdvancedWebServer                                                                                                                                                     
{                                                                                                                                                                                                         
  "compiler_out": "Sketch uses 701109 bytes (53%) of program storage space. Maximum is 1310720 bytes.\nGlobal variables use 39840 bytes (12%) of dynamic memory, leaving 287840 bytes for local variables.
 Maximum is 327680 bytes.\n",                                                                                                                                                                             
  "compiler_err": "",
... SNIP ...
  },
  "success": true
}

From the above, by only requesting the compilation database the compilation fails.

Expected behavior

No error should be generated.

Environment

• CLI version (output of arduino-cli version): arduino-cli alpha Version: 0.19.3 Commit: 12f1afc Date: 2021-10-11T15:14:04Z
• OS and platform: Linux with an ESP32 board

[per1234]

I'll add some additional information:
The command that was shared is far more than is needed for a minimal demonstration. The only two requirements are:

• compile for board of the esp32:esp32 boards platform
• use the --only-compilation-database flag

arduino-cli compile --fqbn esp32:esp32:featheresp32 --only-compilation-database

This is specific to the configuration of the ESP32 platform (i.e., it won't occur when compiling for another platform such as arduino:avr). It is the result of this feature:
espressif/arduino-esp32#5237

Note the comment there:

The script has been taken from stm32duino's Arduino_Core_STM32 package

The same type of issue occurs when compiling for boards of the STMicroelectronics:stm32 boards platform (except the missing file is named build.opt):

$ arduino-cli compile --fqbn STMicroelectronics:stm32:GenF0 --only-compilation-database Foo
arm-none-eabi-g++: error: C:\Users\per\AppData\Local\Temp\arduino-sketch-E8AF847218556EB3A395D00D1B675AD8/sketch/build.opt: No such file or directory

Error during build: exit status 1

The problem seems to be that the recipe.hooks.prebuild.NUMBER.pattern hook doesn't run when using the --only-compilation-database flag, so the required build_opt.h/build.opt file is missing from the build folder.