build directory keeps deleted files resulting in "multiple definition" errors during link

[phord]

When I rename a source file in an arduino project and the "output" folder is set in arduino.json, I get a build error because the old filename is still in the output folder.

1. I created a project with the "Blink.ino" sketch and this arduino.json:

   {
   "board": "esp8266:esp8266:oak",
   "configuration": "xtal=80,vt=flash,exception=legacy,ssl=all,eesz=4M2M,ip=lm2f,dbg=Disabled,lvl=None____,wipe=none,baud=921600",
   "sketch": "Blink.ino",
   "output": "../test-build"
   }

2. I created a file named src/foo.cpp to be included with my project. It defines a single function.

3. I compiled the project with Arduino: Verify. The build succeeded.

4. I clicked on "bar.cpp" in the File Explorer and pressed F2 to rename it.

5. I changed the name to bar.cpp.

6. I compiled the project with Arduino: Verify. The build failed with "multiple definition.

7. When I look in my test-build/sketch directory, I see both foo.cpp and bar.cpp and related build output.

[phord]

fwiw - I get the same error if I rename foo.cpp from my shell instead of renaming it in the editor. But I do not see this error if I delete foo.cpp, either from the shell or from VS Code.

$ find .                   
./.vscode
./.vscode/settings.json
./.vscode/arduino.json
./.vscode/c_cpp_properties.json
./src
./src/foo.cpp
./Blink.ino

[Starting] Verify sketch - Blink.ino
Please see the build logs in Output path: /home/phord/test-build
Picked up JAVA_TOOL_OPTIONS: 
Loading configuration...
Initializing packages...
Preparing boards...
Verifying...
Executable segment sizes:
IROM   : 228508          - code in flash         (default or ICACHE_FLASH_ATTR) 
IRAM   : 26784   / 32768 - code in IRAM          (ICACHE_RAM_ATTR, ISRs...) 
DATA   : 1252  )         - initialized variables (global, static) in RAM/HEAP 
RODATA : 688   ) / 81920 - constants             (global, static) in RAM/HEAP 
BSS    : 24880 )         - zeroed variables      (global, static) in RAM/HEAP 
Sketch uses 257232 bytes (24%) of program storage space. Maximum is 1044464 bytes.
Global variables use 26820 bytes (32%) of dynamic memory, leaving 55100 bytes for local variables. Maximum is 81920 bytes.
[Done] Finished verify sketch - Blink.ino

$ find ../test-build/sketch
../test-build/sketch
../test-build/sketch/Blink.ino.cpp
../test-build/sketch/src
../test-build/sketch/src/foo.cpp
../test-build/sketch/src/foo.cpp.d
../test-build/sketch/src/foo.cpp.o
../test-build/sketch/Blink.ino.cpp.d
../test-build/sketch/Blink.ino.cpp.o

Now, I just rename foo.cpp to bar.cpp, and the build fails.

$ mv src/foo.cpp src/bar.cpp
$ find .                    
./.vscode
./.vscode/settings.json
./.vscode/arduino.json
./.vscode/c_cpp_properties.json
./src
./src/bar.cpp
./Blink.ino

[Starting] Verify sketch - Blink.ino
Please see the build logs in Output path: /home/phord/test-build
Picked up JAVA_TOOL_OPTIONS: 
Loading configuration...
Initializing packages...
Preparing boards...
Verifying...
/home/phord/.arduino15/packages/esp8266/tools/xtensa-lx106-elf-gcc/2.5.0-4-b40a506/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/bin/ld: sketch/src/foo.cpp.o: in function `some_function()':
sketch/src/foo.cpp:1: multiple definition of `some_function()'; sketch/src/bar.cpp.o:sketch/src/bar.cpp:1: first defined here
collect2: error: ld returned 1 exit status
exit status 1
[Error] Exit with code=1

$ find ../test-build/sketch 
../test-build/sketch
../test-build/sketch/Blink.ino.cpp
../test-build/sketch/src
../test-build/sketch/src/foo.cpp
../test-build/sketch/src/foo.cpp.d
../test-build/sketch/src/foo.cpp.o
../test-build/sketch/src/bar.cpp
../test-build/sketch/src/bar.cpp.d
../test-build/sketch/src/bar.cpp.o
../test-build/sketch/Blink.ino.cpp.d
../test-build/sketch/Blink.ino.cpp.o

The only way to get things working again is to find my build output folder and manually delete the old sketch files there.

[hayden-servaenergy]

Still experiencing this issue with v0.6.0. Having a "Build Directory Clean" command would be great for this, at least as a temporary fix.