Docker build fails with "cannot move 'ffmpeg-build/.../ffmpeg' to a subdirectory of itself"

[alexmbird]

Just tried to build the Docker image and got:

$ docker build -t atrac-api .
...

 => ERROR [builder 7/7] RUN mv ffmpeg-build/artifacts/ffmpeg-*-linux-gnu/bin/ffmpeg .                               5.8s
------
 > [builder 7/7] RUN mv ffmpeg-build/artifacts/ffmpeg-*-linux-gnu/bin/ffmpeg .:
#0 0.627 mv: cannot move 'ffmpeg-build/artifacts/ffmpeg-5.1.2-audio-x86_64-linux-gnu/bin/ffmpeg' to a subdirectory of itself, './ffmpeg'
------
Dockerfile:8
--------------------
   6 |     RUN echo "FFMPEG_CONFIGURE_FLAGS+=(--enable-encoder=pcm_s16le --enable-muxer=wav --enable-filter=loudnorm --enable-filter=aresample --enable-filter=replaygain --enable-filter=volume)" >> ffmpeg-build/common.sh
   7 |     RUN ffmpeg-build/build-linux.sh
   8 | >>> RUN mv ffmpeg-build/artifacts/ffmpeg-*-linux-gnu/bin/ffmpeg .
   9 |
  10 |     FROM python:3.11-slim
--------------------
ERROR: failed to solve: process "/bin/sh -c mv ffmpeg-build/artifacts/ffmpeg-*-linux-gnu/bin/ffmpeg ." did not complete successfully: exit code: 1

[alexmbird]

No idea why this is happening - there isn't a clashing ffmpeg in /root - but switching mv ffmpeg-build/artifacts/ffmpeg-*-linux-gnu/bin/ffmpeg . to a cp ... seems to have cured it