Warnings for .pde file are emitted even if the current dir is not a sketch

[cmaglie]

Describe the problem

The warning Sketches with .pde extension are deprecated, please rename the following files to .ino is emitted even if the current directory is not a sketch. This means that a scan of the subdirectories is performed even if it is useless.

To reproduce

For example if you run arduino-cli compile in the git root folder of the arduino-cli repository:

~/Workspace/arduino-cli ⎇  master $ arduino-cli compile
Sketches with .pde extension are deprecated, please rename the following files to .ino:
 - /home/cmaglie/Workspace/arduino-cli/arduino/builder/testdata/TestLoadSketchFolder/old.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/builder/testdata/TestLoadSketchFolderBothInoAndPde/TestLoadSketchFolderBothInoAndPde.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/builder/testdata/TestLoadSketchFolderBothInoAndPde/old.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/builder/testdata/TestLoadSketchFolderPde/TestLoadSketchFolderPde.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/builder/testdata/TestLoadSketchFolderPde/old.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/builder/testdata/TestLoadSketchFolderSymlinkSrc/old.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/libraries/testdata/TestLibExamples/examples/MultipleFiles/MultipleFiles.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/sketch/testdata/SketchBothInoAndPde/SketchBothInoAndPde.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/sketch/testdata/SketchMultipleMainFiles/SketchMultipleMainFiles.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/sketch/testdata/SketchPde/SketchPde.pde
 - /home/cmaglie/Workspace/arduino-cli/arduino/sketch/testdata/SketchSymlinkSrc/old.pde
 - /home/cmaglie/Workspace/arduino-cli/internal/integrationtest/compile_4/testdata/SketchWithMergedSketchAndBootloader/old.pde
 - /home/cmaglie/Workspace/arduino-cli/internal/integrationtest/testdata/sketch_multiple_main_files/sketch_multiple_main_files.pde
 - /home/cmaglie/Workspace/arduino-cli/internal/integrationtest/testdata/sketch_pde_main_file/sketch_pde_main_file.pde
 - /home/cmaglie/Workspace/arduino-cli/internal/integrationtest/testdata/sketch_simple/old.pde
Can't open sketch: main file missing from sketch: /home/cmaglie/Workspace/arduino-cli/arduino-cli.ino
~/Workspace/arduino-cli ⎇  master $ 

Expected behavior

~/Workspace/arduino-cli ⎇  master $ arduino-cli compile
Can't open sketch: main file missing from sketch: /home/cmaglie/Workspace/arduino-cli/arduino-cli.ino
~/Workspace/arduino-cli ⎇  master $

Arduino CLI version

nightly

Operating system

N/A

Operating system version

N/A

Additional context

No response

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the nightly build
• My report contains all necessary details