Setting build-path to current dir

[wayoda]

Compile a sketch with -build-path = . (the current working dir)

wayoda@shredder:~/sketchbook/empty$ arduino-builder -build-path . -fqbn arduino:avr:nano -hardware /home/wayoda/opt/arduino/arduino-1.6.6/hardware -tools /home/wayoda/opt/arduino/arduino-1.6.6/tools/ -verbose -debug-level 10 empty.ino 

Run the command serveral times. For every run of the builder a recursive sketch-dir is created

wayoda@shredder:~/sketchbook/empty$ tree
.
├── build.options.json
├── empty.ino
└── sketch
    ├── empty.ino.cpp
    └── sketch
        ├── empty.ino.cpp
        └── sketch
            ├── empty.ino.cpp
            └── sketch
                ├── empty.ino.cpp
                └── sketch
                    ├── empty.ino.cpp
                    └── sketch
                        ├── empty.ino.cpp
                        └── sketch
                            ├── empty.ino.cpp
                            └── sketch
                                ├── empty.ino.cpp
                                └── sketch
                                    ├── empty.ino.cpp
                                    └── sketch
                                        ├── empty.ino.cpp
                                        └── sketch
                                            ├── empty.ino.cpp
                                            └── sketch
                                                ├── empty.ino.cpp
                                                └── sketch
                                                    └── empty.ino.cpp

13 directories, 15 files

[ffissore]

Ok it took a bit of investigation but the reason if quite simple. In order to solve arduino/Arduino#3080 (fixed with arduino/Arduino#3435), the whole sketch folder is copied to the build path "sketch" subfolder. Compiling twice, doubles folders nesting, and so on.
Since we can't avoid copying the whole sketch folder to build path "sketch" subfolder, specifying a build path equal to the sketch folder is now illegal, and builder will complain with "Sketch cannot be located in build path. Please specify a different build path"