fix: filter empty segments in colon-separated env var parsing by baby-joel · Pull Request #9076 · jdx/mise

baby-joel · 2026-04-13T21:23:15Z

Problem

MISE_OVERRIDE_CONFIG_FILENAMES=""\ (empty string) causes mise to panic:

The application panicked (crashed).
Message: called `Option::unwrap()` on a `None` value
Location: src/config/config_file/config_root.rs:49

When the env var is set to an empty string, split(':') produces [""] — a set with one empty-string entry. This non-empty set replaces the default config filename list, injecting "" as a config path. During Config::load, the empty path absolutizes to the filesystem root (/), which has no parent directory, causing config_root() to panic on path.parent().unwrap().

How this happens in practice

vfox plugins that spawn nested mise processes (e.g., mise -C <plugin-path> run install) inherit the parent's MISE_OVERRIDE_CONFIG_FILENAMES. When the parent sets it to mise.ci.toml, the child process looks for a non-existent mise.ci.toml in the plugin directory. Unsetting it via VAR='' command is a common workaround — but the empty string triggers this panic.

Fix

Add .filter(|s| !s.is_empty()) to both colon-split expressions in src/env.rs:

MISE_OVERRIDE_CONFIG_FILENAMES
MISE_OVERRIDE_TOOL_VERSIONS_FILENAMES

This also correctly handles edge cases like trailing/leading colons (:mise.ci.toml:) and consecutive colons.

Tests

e2e test: test_override_config_filenames_empty — verifies empty string, colon-only, and leading/trailing colons all work without panicking
unit test: test_split_colon_filters_empty_segments — documents the correct filter pattern for all edge cases

gemini-code-assist

Code Review

This pull request addresses a potential panic when environment variables like MISE_OVERRIDE_CONFIG_FILENAMES are set to empty strings or contain empty segments. The fix involves filtering out empty strings after splitting by colons in src/env.rs. Additionally, a new e2e regression test and a unit test have been added to ensure correct behavior for various edge cases. I have no feedback to provide.

greptile-apps · 2026-04-13T21:26:50Z

Greptile Summary

This PR fixes a panic in config_root() triggered when MISE_OVERRIDE_CONFIG_FILENAMES=\"\" is set to an empty string. The fix extracts a split_colon_list helper that filters empty segments produced by empty strings, leading/trailing colons, or consecutive colons, and applies it to both MISE_OVERRIDE_CONFIG_FILENAMES and MISE_OVERRIDE_TOOL_VERSIONS_FILENAMES in src/env.rs.

Confidence Score: 5/5

Safe to merge — the fix is minimal, correct, and well-tested; no P0/P1 issues found.

The panic fix is verified by tracing from split_colon_list through the is_empty() guard in config/mod.rs. Unit and e2e tests cover the key edge cases. All remaining observations are P2.

No files require special attention.

Important Files Changed

Filename	Overview
src/env.rs	Extracts `split_colon_list` helper that filters empty segments; applied correctly to both override filename env vars. Unit test covers all edge cases.
e2e/config/test_override_config_filenames_empty	Adds regression e2e test covering empty string, colon-only, and leading/trailing colon cases for `MISE_OVERRIDE_CONFIG_FILENAMES`; no test for the parallel `MISE_OVERRIDE_TOOL_VERSIONS_FILENAMES` fix (flagged in a prior comment).

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["env var set? (e.g. MISE_OVERRIDE_CONFIG_FILENAMES)"] -->|"Err (unset)"| B["miserc fallback / unwrap_or_default\n→ empty IndexSet"]
    A -->|"Ok(v) == 'none'"| C["Some(empty IndexSet)"]
    A -->|"Ok(v)"| D["split_colon_list(v)"]
    D --> E["split(':')"]
    E --> F["filter empty segments"]
    F --> G["collect → IndexSet"]
    G --> H{{"is_empty()?"}}
    B --> H
    H -->|"true"| I["use default config filenames\n(.config/mise/config.toml, mise.toml, …)"]
    H -->|"false"| J["use override filenames only"]

_{Reviews (4): Last reviewed commit: "[autofix.ci] apply automated fixes" | Re-trigger Greptile}

When MISE_OVERRIDE_CONFIG_FILENAMES is set to an empty string, split(':') produces [""] — a set containing one empty string. This non-empty set replaces the default config filename list, injecting "" as a config path. During Config::load, this empty path reaches config_root() which panics on path.parent().unwrap() because the absolutized empty string resolves to the filesystem root (/). The e2e test reproduces the exact panic seen in CI when vfox plugins spawn nested mise processes that inherit the parent's MISE_OVERRIDE_CONFIG_FILENAMES. Also adds a unit test documenting the correct filter pattern.

MISE_OVERRIDE_CONFIG_FILENAMES and MISE_OVERRIDE_TOOL_VERSIONS_FILENAMES split their values on ':' but don't filter empty segments. When set to an empty string (e.g., by a parent process clearing it via VAR='' cmd), split(':') produces [""] — a one-element set containing an empty string. This non-empty set replaces the default config filename list and injects "" as a config path. During Config::load, the empty path absolutizes to the filesystem root, which has no parent directory, causing config_root() to panic on path.parent().unwrap(). Extract split_colon_list() helper that filters empty segments. Both env vars now use it. Also handles trailing/leading colons and consecutive colons gracefully.

@webkaz

### 🚀 Features - **(npm)** use --min-release-age for npm 11.10.0+ supply chain protection by @webkaz in [#9072](#9072) - **(registry)** add openfga by @mnm364 in [#9084](#9084) - **(task)** allow to set confirmation default by @roele in [#9089](#9089) - support os/arch compound syntax in tool os filtering by @RobertDeRose in [#9088](#9088) ### 🐛 Bug Fixes - **(activate)** export __MISE_EXE and resolve bare ARGV0 to absolute path by @fru1tworld in [#9081](#9081) - **(install)** support aliased installs sharing a backend by @jdx in [#9093](#9093) - **(shim)** use which_no_shims when resolving mise binary in reshim and doctor by @kevinswiber in [#9071](#9071) - filter empty segments in colon-separated env var parsing by @baby-joel in [#9076](#9076) ### 📚 Documentation - fix wrong file reference to forgejo backend implemenation by @roele in [#9090](#9090) - fix cli token command for token resolution by @roele in [#9077](#9077) ### 📦 Registry - add trzsz-go ([aqua:trzsz/trzsz-go](https://github.com/trzsz/trzsz-go)) by @ZeroAurora in [#9083](#9083) - add copilot ([aqua:github/copilot-cli](https://github.com/github/copilot-cli)) by @risu729 in [#9082](#9082) ### Chore - add AGENTS.md symlink by @jdx in [#9094](#9094) ### New Contributors - @kevinswiber made their first contribution in [#9071](#9071) - @webkaz made their first contribution in [#9072](#9072) - @RobertDeRose made their first contribution in [#9088](#9088) ## 📦 Aqua Registry Updates #### New Packages (7) - [`IBM-Cloud/ibm-cloud-cli-release`](https://github.com/IBM-Cloud/ibm-cloud-cli-release) - [`max-sixty/worktrunk`](https://github.com/max-sixty/worktrunk) - [`micelio.dev/hif`](https://github.com/micelio.dev/hif) - [`pgplex/pgschema`](https://github.com/pgplex/pgschema) - [`rose-pine/rose-pine-bloom`](https://github.com/rose-pine/rose-pine-bloom) - [`santosr2/TerraTidy`](https://github.com/santosr2/TerraTidy) - [`trzsz/trzsz-go`](https://github.com/trzsz/trzsz-go) #### Updated Packages (3) - [`mvdan/sh`](https://github.com/mvdan/sh) - [`rvben/rumdl`](https://github.com/rvben/rumdl) - [`temporalio/temporal`](https://github.com/temporalio/temporal)

@jdx

## [2026.4.14](https://github.com/jdx/mise/compare/v2026.4.13..v2026.4.14) - 2026-04-15 ### Chore - bump sigstore-verification by @jdx in [#9128](jdx/mise#9128) ## [2026.4.13](https://github.com/jdx/mise/compare/v2026.4.12..v2026.4.13) - 2026-04-15 ### 🐛 Bug Fixes - **(go)** honor install_before for module versions by @mariusvniekerk in [#9097](jdx/mise#9097) - **(vfox-plugin)** support Git URL with commit hash for mise.toml by @Oyami-Srk in [#9099](jdx/mise#9099) - `MISE_FETCH_REMOTE_VERSIONS_CACHE` not respected by @mcncl in [#9096](jdx/mise#9096) ### 📦️ Dependency Updates - unblock cargo-deny advisories check by @jdx in [#9112](jdx/mise#9112) ### New Contributors - @mariusvniekerk made their first contribution in [#9097](jdx/mise#9097) - @mcncl made their first contribution in [#9096](jdx/mise#9096) - @Oyami-Srk made their first contribution in [#9099](jdx/mise#9099) ## [2026.4.12](https://github.com/jdx/mise/compare/v2026.4.11..v2026.4.12) - 2026-04-15 ### 🚀 Features - **(npm)** use --min-release-age for npm 11.10.0+ supply chain protection by @webkaz in [#9072](jdx/mise#9072) - **(registry)** add openfga by @mnm364 in [#9084](jdx/mise#9084) - **(task)** allow to set confirmation default by @roele in [#9089](jdx/mise#9089) - support os/arch compound syntax in tool os filtering by @RobertDeRose in [#9088](jdx/mise#9088) ### 🐛 Bug Fixes - **(activate)** export __MISE_EXE and resolve bare ARGV0 to absolute path by @fru1tworld in [#9081](jdx/mise#9081) - **(install)** support aliased installs sharing a backend by @jdx in [#9093](jdx/mise#9093) - **(shim)** use which_no_shims when resolving mise binary in reshim and doctor by @kevinswiber in [#9071](jdx/mise#9071) - filter empty segments in colon-separated env var parsing by @baby-joel in [#9076](jdx/mise#9076) ### 📚 Documentation - fix wrong file reference to forgejo backend implemenation by @roele in [#9090](jdx/mise#9090) - fix cli token command for token resolution by @roele in [#9077](jdx/mise#9077)

gemini-code-assist Bot reviewed Apr 13, 2026

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baby-joel force-pushed the baby-joel/empty-override-config-filenames branch from 7fe9e8e to 7ae76d1 Compare April 13, 2026 21:26

greptile-apps Bot reviewed Apr 13, 2026

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Comment thread e2e/config/test_override_config_filenames_empty Outdated

Comment thread e2e/config/test_override_config_filenames_empty

baby-joel force-pushed the baby-joel/empty-override-config-filenames branch from 7ae76d1 to 4414ec2 Compare April 13, 2026 21:28

baby-joel added 2 commits April 13, 2026 17:29

baby-joel force-pushed the baby-joel/empty-override-config-filenames branch from 4414ec2 to f085403 Compare April 13, 2026 21:31

[autofix.ci] apply automated fixes

4f5c5d8

jdx merged commit 5188f41 into jdx:main Apr 14, 2026
34 checks passed

mise-en-dev mentioned this pull request Apr 14, 2026

chore: release 2026.4.12 #9080

Merged

BrewTestBot mentioned this pull request Apr 15, 2026

mise 2026.4.12 Homebrew/homebrew-core#277729

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fix: filter empty segments in colon-separated env var parsing#9076

fix: filter empty segments in colon-separated env var parsing#9076
jdx merged 3 commits intojdx:mainfrom
KnickKnackLabs:baby-joel/empty-override-config-filenames

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baby-joel commented Apr 13, 2026

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Confidence Score: 5/5

Important Files Changed

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