fix(task): remove deprecated `# mise` task header syntax by jdx · Pull Request #8403 · jdx/mise

jdx · 2026-03-02T01:03:21Z

Summary

Remove the old deprecated # mise ... file task header syntax that was scheduled for removal in 2026.3.0
Remove the debug_assert! that was causing panics in debug builds now that it's March 2026
Only the #MISE / # [MISE] / //MISE / ::MISE syntax is now supported

Fixes the panic in the release-plz CI job: https://github.com/jdx/mise/actions/runs/22556327882/job/65334256964

Test plan

mise run lint-fix passes
Docs already use #MISE syntax exclusively — no doc changes needed
E2E tests already use #MISE syntax exclusively — no test changes needed

🤖 Generated with Claude Code

Note

Medium Risk
Removes backward-compatible parsing for the deprecated # mise ... task header format, which may break users still relying on it. Change is localized to task file header parsing and associated tests.

Overview
Task file header parsing now only recognizes the #MISE / # [MISE] (and related ///::) header formats; the deprecated # mise ... header syntax, its deprecation warning, and the debug-only assertion guarding its removal are deleted.

Tests are updated to use #MISE headers when validating invalid-TOML error handling.

^{Written by Cursor Bugbot for commit 781a543. This will update automatically on new commits. Configure here.}

The old `# mise ...` syntax was deprecated in favor of `#MISE ...` and scheduled for removal in 2026.3.0. Remove the old syntax handling and the debug_assert reminder that was causing panics in debug builds. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gemini-code-assist · 2026-03-02T01:03:34Z

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request streamlines the task header parsing logic by removing a previously deprecated syntax and an associated debug assertion. The changes ensure that only the modern, standardized task header formats are recognized, resolving a panic in CI and simplifying the codebase.

Highlights

Deprecated Syntax Removal: Removed the old # mise ... file task header syntax, which was scheduled for removal in mise 2026.3.0.
Debug Assertion Removal: Removed a debug_assert! that was causing panics in debug builds, now that the scheduled removal date (March 2026) has passed.
Supported Syntax: Ensured only the #MISE, #[MISE], //MISE, and ::MISE syntaxes are now supported for task headers.

Changelog

src/task/mod.rs
- Removed the VERSION import as it's no longer needed for the debug_assert!.
- Eliminated the debug_assert! that checked for the 2026.3 version, as the deprecation period has ended.
- Removed the conditional logic that handled the deprecated # mise ... task header syntax, consolidating parsing to only support the current #MISE variants.

Activity

Identified and fixed a panic occurring in the release-plz CI job.
Confirmed that mise run lint-fix passes.
Verified that documentation and E2E tests already exclusively use the new #MISE syntax, requiring no further changes.

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Code Review

This pull request correctly removes the deprecated # mise task header syntax and the associated debug_assert!. The changes are clean and align with the goal of the PR. The included comment regarding a unit test that will likely fail due to this change and needs to be updated is valid.

gemini-code-assist · 2026-03-02T01:05:24Z

            .filter_map(|line| {
-                debug_assert!(
-                    !VERSION.starts_with("2026.3"),
-                    "remove old syntax `# mise`"
-                );
-                if let Some(captures) =
-                    regex!(r"^(?:#|//|::)(?:MISE| ?\[MISE\]) ([a-z0-9_.-]+=[^\n]+)$").captures(line)
-                {
-                    Some(captures)
-                } else if let Some(captures) = regex!(r"^(?:#|//) mise ([a-z0-9_.-]+=[^\n]+)$")
-                    .captures(line)
-                {
-                    deprecated!(
-                        "file_task_headers_old_syntax",
-                        "The `# mise ...` syntax for task headers is deprecated and will be removed in mise 2026.3.0. Use the new `#MISE ...` syntax instead."
-                    );
-                    Some(captures)
-                } else {
-                    None
-                }
+                regex!(r"^(?:#|//|::)(?:MISE| ?\[MISE\]) ([a-z0-9_.-]+=[^\n]+)$").captures(line)
            })


This change correctly removes support for the deprecated # mise syntax. However, this will likely cause the unit test test_from_path_invalid_toml (in this same file) to fail. That test asserts that invalid TOML in a # mise header causes an error. With this change, the line is simply ignored.

Please consider updating the test to assert that parsing a file with the old syntax now succeeds without error. For example:

#[tokio::test] async fn test_from_path_invalid_toml() { // ... setup ... fs::write( &task_path, r#"#!/bin/bash # mise description="test task" # mise env={invalid=toml=here} echo "hello world" "#, ) .unwrap(); let result = Task::from_path(&config, &task_path, temp_dir.path(), temp_dir.path()).await; // The old `# mise` syntax is now ignored, so this should not produce an error. assert!(result.is_ok()); }

cursor

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

greptile-apps · 2026-03-02T01:07:38Z

Greptile Summary

This PR removes the deprecated # mise task header syntax that was scheduled for removal in 2026.3.0 (now past due). The changes simplify the code by removing the old regex pattern, deprecation warning, and the debug_assert! that was causing panics in debug builds.

Key changes:

Removed VERSION import (no longer needed)
Removed debug_assert! that panicked in 2026.3+ versions
Removed regex matching old # mise syntax
Removed deprecation warning for old syntax
Only #MISE, # [MISE], //MISE, and ::MISE syntax is now supported

Issue found:

Test test_from_path_invalid_toml at lines 1624-1625 still uses the old deprecated syntax and will fail to test invalid TOML parsing as intended

Confidence Score: 3/5

This PR has the right approach but contains a test that will no longer function correctly
The deprecation removal is correctly timed and well-executed, but the overlooked test using old syntax will break the test's intended validation of invalid TOML parsing
src/task/mod.rs - lines 1624-1625 need to be updated to use #MISE syntax

Important Files Changed

Filename	Overview
src/task/mod.rs	Removes deprecated `# mise` task header syntax and debug assertion, but test at line 1624 still uses old syntax

_{Last reviewed commit: 19c5f18}

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

greptile-apps · 2026-03-02T01:07:46Z

Additional Comments (1)

src/task/mod.rs
test uses the old deprecated # mise syntax which won't be recognized after this change - update to #MISE syntax

#MISE description="test task"
#MISE env={invalid=toml=here}

The test_from_path_invalid_toml test was still using the old deprecated `# mise` syntax which is no longer parsed after the previous commit. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

github-actions · 2026-03-02T01:31:15Z

Hyperfine Performance

`mise x -- echo`

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`mise-2026.2.24 x -- echo`	28.8 ± 0.8	27.4	34.5	1.20 ± 0.05
`mise x -- echo`	23.9 ± 0.8	22.9	33.2	1.00
✅ Performance improvement for `x -- echo` is 20%

`mise env`

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`mise-2026.2.24 env`	28.0 ± 0.6	26.9	33.9	1.19 ± 0.07
`mise env`	23.5 ± 1.3	22.5	49.6	1.00
✅ Performance improvement for `env` is 19%

`mise hook-env`

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`mise-2026.2.24 hook-env`	29.1 ± 0.8	27.6	34.7	1.21 ± 0.04
`mise hook-env`	24.1 ± 0.6	23.2	27.1	1.00
✅ Performance improvement for `hook-env` is 21%

`mise ls`

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`mise-2026.2.24 ls`	23.1 ± 0.6	22.1	28.9	1.06 ± 0.04
`mise ls`	21.8 ± 0.5	21.0	25.1	1.00

`xtasks/test/perf`

Command	mise-2026.2.24	mise	Variance
install (cached)	162ms	150ms	+8%
ls (cached)	89ms	81ms	+9%
bin-paths (cached)	96ms	✅ 85ms	+12%
task-ls (cached)	839ms	822ms	+2%

✅ Performance improvement: bin-paths cached is 12%

@jdx

### 🚀 Features - **(hooks)** add task references to hooks and watch_files by @jdx in [#8400](#8400) - **(prepare)** add git-submodule built-in provider by @jdx in [#8407](#8407) - **(prepare)** add human-readable stale reasons to prepare output by @jdx in [#8408](#8408) - **(prepare)** add dependency ordering to prepare steps by @jdx in [#8401](#8401) - **(prepare)** add --explain flag for provider diagnostics by @jdx in [#8409](#8409) - **(prepare)** add per-provider timeout support by @jdx in [#8405](#8405) - **(prepare)** add blake3 content-hash freshness checking by @jdx in [#8404](#8404) - **(tasks)** monorepo vars and per-task vars by @halms in [#8248](#8248) ### 🐛 Bug Fixes - **(aqua)** restore bin_paths disk cache with fresh_file invalidation by @jdx in [#8398](#8398) - **(idiomatic)** use generic parser for idiomatic files by @risu729 in [#8171](#8171) - **(install)** apply precompiled options to all platforms in lockfile by @jdx in [#8396](#8396) - **(install)** normalize "v" prefix when matching lockfile versions by @jdx in [#8413](#8413) - **(prepare)** improve git submodule parser and fix check_staleness error handling by @jdx in [#8412](#8412) - **(python)** respect precompiled settings in lock file generation by @jdx in [#8399](#8399) - **(python)** clarify uv_venv_auto docs + prevent uv shim recursion in venv creation by @halms in [#8402](#8402) - **(task)** remove deprecated `# mise` task header syntax by @jdx in [#8403](#8403) - **(vfox)** avoid eager metadata loading during config file detection by @jdx in [#8397](#8397) - clarify GitHub attestations to be artifact ones by @scop in [#8394](#8394) - ignore comments in idiomatic version files by @iloveitaly in [#7682](#7682) ### 🚜 Refactor - unify archive detection by @risu729 in [#8137](#8137) ### 📚 Documentation - remove duplicated docs for npm.package_manager by @risu729 in [#8414](#8414)

gemini-code-assist Bot reviewed Mar 2, 2026

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cursor Bot reviewed Mar 2, 2026

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Comment thread src/task/mod.rs

greptile-apps Bot reviewed Mar 2, 2026

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fix(task): update test to use new #MISE header syntax

781a543

The test_from_path_invalid_toml test was still using the old deprecated `# mise` syntax which is no longer parsed after the previous commit. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

jdx enabled auto-merge (squash) March 2, 2026 01:18

jdx merged commit 93c8efe into main Mar 2, 2026
35 checks passed

jdx deleted the fix/remove-deprecated-mise-task-header-syntax branch March 2, 2026 01:25

mise-en-dev mentioned this pull request Mar 2, 2026

chore: release 2026.3.0 #8406

Merged

BrewTestBot mentioned this pull request Mar 2, 2026

mise 2026.3.0 Homebrew/homebrew-core#270150

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fix(task): remove deprecated `# mise` task header syntax#8403

fix(task): remove deprecated `# mise` task header syntax#8403
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fix/remove-deprecated-mise-task-header-syntax

jdx commented Mar 2, 2026 •

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jdx commented Mar 2, 2026 • edited by cursor Bot Loading Uh oh! There was an error while loading. Please reload this page.

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Confidence Score: 3/5

Important Files Changed

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Hyperfine Performance

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xtasks/test/perf

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jdx commented Mar 2, 2026 •

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`mise x -- echo`

`mise env`

`mise hook-env`

`mise ls`

`xtasks/test/perf`