fix(windows): correctly identify mise binary without extension

[jdx]

Summary

• Fixes the same issue as fix(windows): correctly identify mise binary without extension #8496 with the cleanup requested by @jdx
• On Windows, argv[0] can resolve to mise (without .exe), mise.bat, or mise.cmd, all of which were incorrectly identified as shims
• Simplifies the IS_RUNNING_AS_SHIM logic by removing #[cfg(unix)]/#[cfg(windows)] blocks and using a single unified check
• Extracts a shared is_mise_binary() helper used by both IS_RUNNING_AS_SHIM and handle_shim() to keep the logic in one place

Credit to @salim-b for identifying and reporting the issue in #8496.

Co-Authored-By: Salim B git@salim.space

Test plan

• Verify mise --help and mise --version work correctly on Windows when argv[0] is mise (without extension)
• Verify shim behavior still works (e.g., node shim correctly identified as a shim)
• Verify mise- prefixed subcommands are not treated as shims

🤖 Generated with Claude Code

---

Note

Low Risk
Small, localized change to binary-name detection; main risk is misclassifying edge-case executable names and altering shim behavior in those cases.

Overview
Fixes Windows shim detection when argv[0] resolves to mise without an extension (or to mise.bat/mise.cmd), which previously caused real mise invocations to be treated as shims.

This replaces the platform-specific comparison logic in IS_RUNNING_AS_SHIM with a shared env::is_mise_binary() helper and updates handle_shim() to use the same check, ensuring consistent behavior for mise, mise.*, and mise-... binaries.

^{Written by Cursor Bugbot for commit 566183a. This will update automatically on new commits. Configure here.}

[gemini-code-assist]

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 resolves a critical bug affecting Windows users where the mise executable was incorrectly classified as a shim when executed without its file extension. The core change involves simplifying and unifying the shim detection mechanism, making it more resilient to platform-specific invocation nuances and ensuring the main mise binary and its subcommands are always correctly recognized, thereby preventing unexpected behavior.

Highlights

• Windows Binary Identification: Corrected an issue where the mise binary on Windows, when invoked without a file extension (e.g., mise instead of mise.exe), was erroneously identified as a shim.
• Simplified Shim Logic: Refactored the IS_RUNNING_AS_SHIM logic to remove platform-specific #[cfg(unix)] and #[cfg(windows)] blocks, creating a single, unified check.
• Robust Binary Name Check: Enhanced the binary name comparison to correctly identify the main mise executable (with or without extensions like .exe, .bat, .cmd) and mise- prefixed subcommands as non-shims.

Changelog

• src/env.rs
  • Removed conditional compilation for mise_bin based on #[cfg(unix)] and #[cfg(windows)].
  • Modified the IS_RUNNING_AS_SHIM boolean expression to explicitly check for "mise", names starting with "mise.", and names starting with "mise-".

Activity

• No human activity has been recorded on this pull request yet.

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[greptile-apps]

Greptile Summary

This PR fixes a Windows-specific bug where argv[0] could resolve to mise (without .exe), mise.bat, or mise.cmd, all of which were incorrectly classified as shims under the old platform-gated check. It extracts a single is_mise_binary() helper used by both IS_RUNNING_AS_SHIM and handle_shim(), replacing a fragile #[cfg(unix)] / #[cfg(windows)] split with a unified, cross-platform predicate.

Key changes:

• is_mise_binary(bin_name) returns true for "mise", any "mise." prefix (Windows extensions), and "mise-" prefix (subcommand aliases)
• IS_RUNNING_AS_SHIM now simply uses !is_mise_binary(bin_name) — no more platform guards
• handle_shim() replaces the overly-broad starts_with("mise") with the new helper, so bizarrely-named binaries like "miseXYZ" are now correctly treated as shims rather than being silently ignored

Test coverage: No unit tests are added for is_mise_binary; given it is the single source of truth for shim detection and is now pub, adding a small test block would guard against future regressions.

Confidence Score: 4/5

• Safe to merge; the fix is correct and strictly improves Windows shim detection with no regressions on Unix.
• The logic change is small, well-reasoned, and directly addresses the reported bug. The only concern is the absence of unit tests for the new public is_mise_binary() function, which is now the central logic for shim detection.
• src/env.rs — the new is_mise_binary function would benefit from unit tests

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["argv[0] / MISE_BIN_NAME"] --> B["is_mise_binary(bin_name)?"]
    B -->|"bin_name == 'mise'"| C["✅ Mise binary\n(not a shim)"]
    B -->|"bin_name.starts_with('mise.')\ne.g. mise.exe, mise.bat, mise.cmd"| C
    B -->|"bin_name.starts_with('mise-')\ne.g. mise-doctor"| C
    B -->|"anything else\ne.g. node, python"| D["🔀 Shim\n(handle_shim runs)"]

    C --> E["IS_RUNNING_AS_SHIM = false\nhandle_shim() returns early"]
    D --> F["IS_RUNNING_AS_SHIM = true\nhandle_shim() executes shim logic"]

Loading

_{Last reviewed commit: 566183a}

[gemini-code-assist]

Code Review

This pull request fixes an issue on Windows where mise without an extension was incorrectly identified as a shim, simplifying the shim detection logic to be platform-agnostic. A security audit found no vulnerabilities in this change. However, a related inconsistency was identified in another part of the codebase that uses a similar but broader check, and it is recommended to update it for better consistency and to prevent potential bugs.

[gemini-code-assist]

This new logic for identifying a non-shim mise invocation is more specific than the check in src/shims.rs:28, which uses a broader bin_name.starts_with("mise"). This inconsistency can lead to unexpected behavior. For example, a binary named miserable would not be executed as a shim by handle_shim(), but IS_RUNNING_AS_SHIM would be true.

To ensure consistent behavior across the application, I recommend aligning the logic in src/shims.rs with this more precise check:

// in src/shims.rs
if (bin_name == "mise" || bin_name.starts_with("mise.") || bin_name.starts_with("mise-")) || cfg!(test) {
    return Ok(());
}

This will make the shim detection more robust and predictable.

[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.3.4 x -- echo	23.9 ± 0.6	22.6	28.2	1.00
mise x -- echo	24.0 ± 0.5	22.8	25.5	1.00 ± 0.03

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.3.4 env	23.6 ± 0.9	22.2	30.3	1.00 ± 0.05
mise env	23.5 ± 0.5	22.3	25.2	1.00

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.3.4 hook-env	23.9 ± 0.5	22.9	25.6	1.00
mise hook-env	24.1 ± 0.5	22.8	28.2	1.01 ± 0.03

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.3.4 ls	23.1 ± 0.4	22.1	25.2	1.00
mise ls	23.2 ± 0.4	22.3	26.1	1.00 ± 0.03

xtasks/test/perf

Command	mise-2026.3.4	mise	Variance
install (cached)	150ms	150ms	+0%
ls (cached)	83ms	83ms	+0%
bin-paths (cached)	86ms	86ms	+0%
task-ls (cached)	820ms	822ms	+0%

[greptile-apps]

is_mise_binary is a new pub function containing the critical shim-detection logic, yet no unit tests are added. Since this function is now the single source of truth for distinguishing mise binaries from shims across both env.rs and shims.rs, it would be valuable to cover edge cases explicitly — especially the Windows-specific ones that motivated this PR.

A minimal test module would help prevent regressions:

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_is_mise_binary() {
        // direct invocations
        assert!(is_mise_binary("mise"));
        assert!(is_mise_binary("mise.exe"));
        assert!(is_mise_binary("mise.bat"));
        assert!(is_mise_binary("mise.cmd"));
        // subcommand aliases
        assert!(is_mise_binary("mise-doctor"));
        assert!(is_mise_binary("mise-outdated"));
        // shims must NOT match
        assert!(!is_mise_binary("node"));
        assert!(!is_mise_binary("python"));
        assert!(!is_mise_binary("miseish")); // no separator → still a shim
    }
}