fix(ci): set UTF-8 locale in e2e Docker image

[jdx]

Summary

• Set LANG=C.UTF-8 and LC_ALL=C.UTF-8 in packaging/e2e/Dockerfile so the e2e image has a UTF-8 locale instead of the default POSIX / ASCII.

Why

backend/test_gem_slow started failing on the release PR (#9780) when ruby 4.0.4 (today's release) was selected as latest. The test runs mise use ruby with MISE_RUBY_COMPILE=true, which forces ruby-build to compile from source.

make install aborts during the rdoc target with:

(ArgumentError) invalid byte sequence in US-ASCII
.../rdoc-7.0.3/lib/rdoc/parser/c.rb:575:in 'String#scan'
make: *** [uncommon.mk:619: rdoc] Error 1

RDoc's C parser reads UTF-8 bytes from sources like object.c, but the container has LC_CTYPE=POSIX (both LANG and LC_ALL were unset), so Ruby treats the input as ASCII and the scan blows up.

Reproduced inside ghcr.io/jdx/mise:e2e on an Ubuntu 24.04 host: fails with POSIX, succeeds with LC_ALL=C.UTF-8. The C.utf8 locale is already present in the image (locale -a confirms), so no extra install is required.

Reviewer notes

• The ghcr.io/jdx/mise:e2e image is only rebuilt by .github/workflows/docker.yml, which fires on v* tag pushes or workflow_dispatch. After merging, the docker workflow needs to be dispatched (or wait for the next tagged release) before CI will pick up the new image.

Test plan

• Merge, then dispatch docker.yml to rebuild and push ghcr.io/jdx/mise:e2e
• Re-run the failing e2e-3 job on the release PR and confirm backend/test_gem_slow passes

🤖 Generated with Claude Code

---

Note

Low Risk
Low risk: only sets LANG/LC_ALL in the e2e Docker image, which should primarily affect locale-dependent behavior (e.g., string encoding) during tests.

Overview
Sets LANG=C.UTF-8 and LC_ALL=C.UTF-8 in packaging/e2e/Dockerfile so the e2e test container runs with a UTF-8 locale instead of the default ASCII/POSIX locale, improving reliability for builds/tests that process non-ASCII source text (e.g., Ruby/RDoc during compilation).

^{Reviewed by Cursor Bugbot for commit 2723b4d. Bugbot is set up for automated code reviews on this repo. Configure here.}

[greptile-apps]

Greptile Summary

Sets LANG=C.UTF-8 and LC_ALL=C.UTF-8 in the e2e Docker image to fix a Ruby-build compilation failure where RDoc's C parser hit UTF-8 bytes under the default POSIX/ASCII locale.

• The two ENV lines are placed early in the Dockerfile (before the RUN layer), so the locale is active for every subsequent build step and for any process that runs inside the container.
• C.UTF-8 is already present in the Ubuntu base image, so no additional locale-gen or package installation is needed.

Confidence Score: 5/5

Safe to merge — the change is a two-line Dockerfile addition with a well-understood, targeted effect.

Both env vars are standard locale settings, C.UTF-8 is confirmed present in the image, and the change has no side-effects on unrelated tooling in the container.

No files require special attention.

Important Files Changed

Filename	Overview
packaging/e2e/Dockerfile	Adds LANG=C.UTF-8 and LC_ALL=C.UTF-8 ENV directives to fix the POSIX/ASCII locale that caused RDoc to blow up on UTF-8 source bytes during ruby-build compilation.

_{Reviews (1): Last reviewed commit: "fix(ci): set UTF-8 locale in e2e Docker ..." | Re-trigger Greptile}

[gemini-code-assist]

Code Review

This pull request updates the packaging/e2e/Dockerfile to include the LANG and LC_ALL environment variables set to C.UTF-8, ensuring consistent locale settings within the container environment. I have no feedback to provide as there were no review comments.

[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.6 x -- echo	17.7 ± 0.5	16.8	20.8	1.00
mise x -- echo	17.9 ± 0.8	16.4	26.5	1.01 ± 0.06

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.6 env	17.5 ± 0.5	16.5	21.0	1.01 ± 0.04
mise env	17.4 ± 0.6	16.4	20.0	1.00

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.6 hook-env	18.4 ± 0.5	17.5	20.5	1.00
mise hook-env	18.5 ± 0.6	17.4	21.7	1.00 ± 0.04

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.6 ls	14.8 ± 0.5	14.0	17.9	1.01 ± 0.05
mise ls	14.7 ± 0.5	13.8	16.9	1.00

xtasks/test/perf

Command	mise-2026.5.6	mise	Variance
install (cached)	115ms	116ms	+0%
ls (cached)	53ms	54ms	-1%
bin-paths (cached)	58ms	58ms	+0%
task-ls (cached)	429ms	427ms	+0%