Running vp env use with fish gives an error

[will-stone]

Describe the bug

When using the fish shell, running vp env use causes the following error:

❯ vp env use
Using Node.js v24.14.0 (resolved from lts)
fish: Unknown command: unset
in function 'vp' with arguments 'env use'

Reproduction

N/A

Steps to reproduce

This involves using the fish shell so apologies but I cannot provide a reproduction repo as it is determined by the shell which cannot be stated in a project.

Using fish shell run vp env use.

System Info

❯ vp env current
VITE+ - The Unified Toolchain for the Web

Environment:
  Version  24.14.0
  Source   lts

Tool Paths:
  node  /Users/user/.vite-plus/js_runtime/node/24.14.0/bin/node
  npm   /Users/user/.vite-plus/js_runtime/node/24.14.0/bin/npm
  npx   /Users/user/.vite-plus/js_runtime/node/24.14.0/bin/npx



VITE+ - The Unified Toolchain for the Web

vp v0.1.13

Local vite-plus:
  vite-plus  Not found

Tools:
  vite             Not found
  rolldown         Not found
  vitest           Not found
  oxfmt            Not found
  oxlint           Not found
  oxlint-tsgolint  Not found
  tsdown           Not found

Environment:
  Package manager  npm vlatest
  Node.js          v24.14.0

fish, version 4.5.0

Used Package Manager

npm

Logs

Validations

• Read the Contributing Guidelines.
• Check that there isn't already an issue for the same bug.
• Confirm this is a Vite+ issue and not an upstream issue (Vite, Vitest, tsdown, Rolldown, or Oxc).
• The provided reproduction is a minimal reproducible example.

[claude]

Analysis

Root cause: FISH_VERSION is a fish built-in global variable, but it is not exported to child processes by default. When the vp fish wrapper function calls command vp $argv, the subprocess does not see FISH_VERSION in its environment, so detect_shell() falls through to Shell::Posix and emits unset VITE_PLUS_NODE_VERSION (POSIX syntax) instead of set -e VITE_PLUS_NODE_VERSION (fish syntax). Fish then fails when trying to eval the POSIX unset command.

Relevant files

• crates/vite_global_cli/src/commands/env/use.rs — detect_shell() checks EnvConfig::fish_version (i.e. FISH_VERSION env var); format_unset() returns fish-specific vs POSIX syntax based on this
• crates/vite_global_cli/src/commands/env/setup.rs (lines 434–456) — generates ~/.vite-plus/env.fish; the vp wrapper function sets VITE_PLUS_ENV_USE_EVAL_ENABLE as a local-exported variable but does not export FISH_VERSION
• crates/vite_shared/src/env_config.rs (line 152) — fish_version: std::env::var("FISH_VERSION").ok()

Is it fixable?

Yes, this is a clear, self-contained bug with a straightforward fix.

Implementation plan

In crates/vite_global_cli/src/commands/env/setup.rs, update the env_fish_content string to export FISH_VERSION alongside VITE_PLUS_ENV_USE_EVAL_ENABLE in the vp wrapper function:

-        set -lx VITE_PLUS_ENV_USE_EVAL_ENABLE 1
-        set -l __vp_out (command vp $argv); or return $status
+        set -lx VITE_PLUS_ENV_USE_EVAL_ENABLE 1
+        set -lx FISH_VERSION $FISH_VERSION
+        set -l __vp_out (command vp $argv); or return $status

set -lx FISH_VERSION $FISH_VERSION creates a local-scope exported copy of the variable, which the vp subprocess will inherit. This lets detect_shell() correctly identify fish and emit set -e VITE_PLUS_NODE_VERSION instead of unset VITE_PLUS_NODE_VERSION.

After the fix:

1. Users who have already run vp setup will need to re-run vp setup (or vp setup --env-only) to regenerate the env.fish file.
2. A snap test covering the fish case (with FISH_VERSION set in the env) would prevent regression.

No changes to Rust code are needed — just the generated fish script template.