error: chmod on config.lock failed: Operation not permitted – Debian

I’m trying to deploy Atlantis on a Cloud Run Gen2 service with a GCS bucket mounted to it via gcsfuse.

Most seems to work fine, the atlantis server starts and can handle requests properly. Files are also written to the GCS bucket through gcsfuse.

But, when Atlantis tries to clone a git repository (as part of the: atlantis plan commmand) it returns the following error:

running git clone --branch f/gcsfuse-cloudrun --depth=1 --single-branch https://xxxxxxxx:<redacted>@github.com/xxxxxxxx/xxxxxxxx.git /app/atlantis/repos/xxxxxxxx/xxxxxxxx/29/default: Cloning into '/app/atlantis/repos/xxxxxxxx/xxxxxxxx/29/default'...
error: chmod on /app/atlantis/repos/xxxxxxxx/xxxxxxxx/29/default/.git/config.lock failed: Operation not permitted
fatal: could not set 'core.filemode' to 'false'
: exit status 128

I believe that I’m very close but I’m not too knowledgeable on Linux file system permissions.

My Dockerfile is as following:

FROM ghcr.io/runatlantis/atlantis:v0.21.1-pre.20221213-debian

USER root

# Install Python
ENV PYTHONUNBUFFERED=1
RUN apt-get update -y
RUN apt-get install -y python3 python3-pip

# Install system dependencies
RUN set -e; 
    apt-get update -y && apt-get install -y 
    tini 
    lsb-release; 
    gcsFuseRepo=gcsfuse-`lsb_release -c -s`; 
    echo "deb http://packages.cloud.google.com/apt $gcsFuseRepo main" | 
    tee /etc/apt/sources.list.d/gcsfuse.list; 
    curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | 
    apt-key add -; 
    apt-get update; 
    apt-get install -y gcsfuse 
    && apt-get clean

# Set fallback mount directory
ENV MNT_DIR /app/atlantis

# Create mount directory for service
RUN mkdir -p ${MNT_DIR}

RUN chown -R atlantis /app/atlantis/
RUN chmod -R 777 /app/atlantis/

WORKDIR  $MNT_DIR

# Copy local code to the container image.
ENV APP_HOME /app
WORKDIR $APP_HOME
COPY gcsfuse_run.sh ./

# Make the script an executable
RUN chmod +x /app/gcsfuse_run.sh

ENTRYPOINT ["/app/gcsfuse_run.sh"]

The entrypoint script ^, is as following:

#!/usr/bin/env bash
set -eo pipefail

echo "Mounting GCS Fuse to $MNT_DIR"
gcsfuse -o allow_other -file-mode=777 -dir-mode=777 --implicit-dirs --debug_gcs --debug_fuse $BUCKET $MNT_DIR 
echo "Mounting completed."

# This is a atlantis provided docker script that comes from the base image
/usr/local/bin/docker-entrypoint.sh server

Help is highly appreciated!