SIGTRAP "Fontconfig error: No writable cache directories" with non-root user not node (1000)

[MikeMcC399]

Issue

If an attempt is made to run a Cypress Docker image using a non-root user that is not node (1000) then Cypress fails with:

Fontconfig error: No writable cache directories
The Test Runner unexpectedly exited via a exit event with signal SIGTRAP

This affects all Cypress Docker images (cypress/base, cypress/browsers, cypress/included & custom images generated from cypress/factory).

Note that GitHub Actions solves this issue exceptionally for user 1001 by mounting a separate writable /github/home directory and passing a HOME environment variable pointing to it.

Steps to reproduce

Ubuntu 24.04.1 LTS, Node.js 22.12.0 LTS, Docker Desktop 4.37.1, cypress/base.

Follow the instructions in Docker build and run for cypress/base as below:

---

In this example we use a customized Dockerfile which bases a new image on cypress/base, copies the complete Cypress project into the image, including installed dependencies, then installs the Cypress binary.

The file is examples/basic/Dockerfile.base and it has the following contents:

FROM cypress/base
COPY . /opt/app
WORKDIR /opt/app
RUN npx cypress install # Install Cypress binary into image

We build the new image, run the container from the image and execute the Cypress command npx cypress run to run the test:

cd examples/basic         # Use a pre-configured simple Cypress E2E project
npm ci                    # Install Cypress
docker build . -f Dockerfile.base -t test-base  # Build a new image
docker run -it --rm --entrypoint bash test-base -c "npx cypress run" # Run Cypress test in container

---

After confirming that the image can be run with the above docker run command, substitute the following command, which fails:

docker run -it --rm --env CYPRESS_SKIP_VERIFY=true --entrypoint bash --user 1001 test-base -c "npx cypress run"

Logs

$ docker run -it --rm --entrypoint bash --env CYPRESS_SKIP_VERIFY=true --user 1001 test-base -c "npx cypress run" # Run Cypress test in container
Fontconfig error: No writable cache directories
Fontconfig error: No writable cache directories
Fontconfig error: No writable cache directories
Fontconfig error: No writable cache directories
The Test Runner unexpectedly exited via a exit event with signal SIGTRAP

Please search Cypress documentation for possible solutions:

https://on.cypress.io

Check if there is a GitHub issue describing this crash:

https://github.com/cypress-io/cypress/issues

Consider opening a new issue.

----------

Platform: linux-x64 (Debian - 12.8)
Cypress Version: 13.17.0

Other

• This is similar to the problem reported in Failed to connect to the bus - Cypress failed to start cypress#30529
• It is also related to cypress docker image root user misconfiguration #914

[MikeMcC399]

A possible workaround is to make the configured /home/node writable for all users:

Workaround

Copy examples/basic/Dockerfile.base to Dockerfile.base.wa and modify the file as follows:

FROM cypress/base
COPY . /opt/app
WORKDIR /opt/app
RUN npx cypress install
RUN chmod -R 777 /home/node
ENV HOME=/home/node
ENV CYPRESS_SKIP_VERIFY=true

cd examples/basic
npm ci
docker build -f Dockerfile.base.wa -t test-base-wa .
docker run -it --rm --entrypoint bash --user 1001 test-base-wa -c "npx cypress run"