fix(ci): pass UTF-8 locale through to e2e tests

[jdx]

Summary

• Add LANG and LC_ALL (defaulting to C.UTF-8) to the env passthrough in e2e/run_test:90-91.

Why

Follow-up to #9820, which set LANG=C.UTF-8 / LC_ALL=C.UTF-8 in the e2e Docker image — but backend/test_gem_slow kept failing because within_isolated_env() uses env -i to clear the environment before each test, and the locale wasn't on the pass-through list. The Dockerfile defaults were stripped before the test process ever started.

Symptom: ruby 4.0.4 source build fails at the rdoc step with (ArgumentError) invalid byte sequence in US-ASCII when rdoc's C parser hits non-ASCII bytes in object.c.

Reproduced inside ghcr.io/jdx/mise:e2e on bamboo (Ubuntu 24.04 host):

• env -i ... mise install ruby@4.0.4 → fails identically to CI
• env -i ... LANG=C.UTF-8 LC_ALL=C.UTF-8 mise install ruby@4.0.4 → succeeds

Test plan

• Re-run failed e2e-3 on release PR #9780 and confirm backend/test_gem_slow passes

🤖 Generated with Claude Code

---

Note

Low Risk
Low risk: only adjusts environment variables for e2e test execution, with no production code or data-path changes.

Overview
E2E test runner now preserves locale settings when running tests in a fully cleared environment (env -i) by explicitly passing through LANG (defaulting to C.UTF-8) and LC_ALL.

This prevents locale-dependent failures (e.g., tooling assuming US-ASCII) during source builds inside CI and the e2e Docker image.

^{Reviewed by Cursor Bugbot for commit b7d7f06. Bugbot is set up for automated code reviews on this repo. Configure here.}

[greptile-apps]

Greptile Summary

Fixes backend/test_gem_slow failures by adding LANG and LC_ALL to the env -i passthrough list in within_isolated_env(), preventing the locale from being stripped before Ruby's rdoc step encounters non-ASCII bytes.

• Adds LANG="${LANG:-C.UTF-8}" so tests always run with a UTF-8 locale even when the environment is cleared.
• Adds LC_ALL="${LC_ALL:-}" to propagate any explicit override from the host; the default is empty rather than C.UTF-8, which is functionally safe (empty LC_ALL falls through to LANG) but inconsistent with the PR description's stated intent.

Confidence Score: 5/5

Safe to merge — a two-line addition to the test harness's environment passthrough list with no production code changes.

The change is confined to the e2e test harness and only adds two well-understood locale variables to env -i's passthrough list. The default values are conservative and match the Docker image's existing settings, so no test behaviour should regress.

No files require special attention.

Important Files Changed

Filename	Overview
e2e/run_test	Adds LANG (default C.UTF-8) and LC_ALL (default empty) to the env passthrough list in within_isolated_env(); one minor inconsistency where LC_ALL's default doesn't match the stated C.UTF-8 intent.

_{Reviews (2): Last reviewed commit: "fix(ci): default only LANG, let LC_ALL p..." | Re-trigger Greptile}

[gemini-code-assist]

Code Review

This pull request modifies the isolated test environment in e2e/run_test by adding default C.UTF-8 values for the LANG and LC_ALL environment variables. A review comment points out that defaulting LC_ALL will override LANG due to environment variable precedence, and suggests only defaulting LANG while passing LC_ALL through without a default to ensure correct locale fallback behavior.

[gemini-code-assist]

Setting a default value for LC_ALL will override LANG even if LANG is explicitly provided in the environment. Since LC_ALL has the highest precedence among locale environment variables, defaulting it to C.UTF-8 here means that any value passed via LANG will be ignored by the test process unless LC_ALL is also explicitly set.

To allow LANG passthrough while still ensuring a UTF-8 default when nothing is specified, it is better to only default LANG and pass LC_ALL through without a default (which results in an empty string, triggering the standard locale fallback to LANG).

    LANG="${LANG:-C.UTF-8}" \
    LC_ALL="${LC_ALL:-}" \

[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.6 x -- echo	19.1 ± 0.9	17.1	22.8	1.00
mise x -- echo	19.7 ± 3.1	17.2	38.2	1.03 ± 0.17

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.6 env	18.6 ± 0.7	16.7	21.9	1.00
mise env	18.8 ± 0.9	16.9	23.1	1.01 ± 0.06

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.6 hook-env	20.1 ± 1.2	18.1	25.2	1.00
mise hook-env	21.8 ± 1.6	18.4	28.7	1.08 ± 0.10

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.6 ls	20.1 ± 1.6	16.5	26.0	1.00
mise ls	20.8 ± 2.1	17.0	31.4	1.03 ± 0.13

xtasks/test/perf

Command	mise-2026.5.6	mise	Variance
install (cached)	137ms	137ms	+0%
ls (cached)	66ms	67ms	-1%
bin-paths (cached)	76ms	74ms	+2%
task-ls (cached)	540ms	546ms	-1%