[ethanleifer]

In fish, the prompt hook ran pyenv activate --quiet before every prompt. The cache from #523 is supposed to skip that call when nothing has changed, but its fish version never matched.

Cause

The fish hook compared the stored mtimes against a quoted string:

-a "(stat -L -f %m $_PYENV_VH_PATHS 2>/dev/null)" = "$_PYENV_VH_MTIMES"

Fish does not run command substitution inside double quotes, so this compared _PYENV_VH_MTIMES against the literal text (stat -L -f %m ...). The comparison was always false. The bash and zsh hooks use "$(stat ...)", which does run, so only fish was affected.

Fix

Run stat into a local list, then compare it quoted:

if test "$PWD" = "$_PYENV_VH_PWD"
  set -l mtimes (stat -L -f %m $_PYENV_VH_PATHS 2>/dev/null)
  if test "$mtimes" = "$_PYENV_VH_MTIMES"
    return $ret
  end
end

_PYENV_VH_MTIMES is stored as a list from (stat ...). Quoting both lists joins them with spaces the same way, so they compare correctly with one or many paths.

I avoided "$(...)" for two reasons. It needs fish 3.4 or later, and it keeps newlines, so it wouldn't match the stored list. As before, stat only runs when $PWD is unchanged.

Testing

• The bats suite passes with Bats 1.10.0, as in CI: 111 of 111 on macOS. test/init.bats "outputs fish-specific syntax" is updated for the new output. It fails against the old hook code.
• I tested the generated hook in fish 4.9.3 with a stub pyenv that counts activate calls:

Step	Calls on master	Calls with this fix
First prompt	1	1
Second and third prompt in the same directory	3	1
After cd .., then another prompt	5	2
New .python-version in a parent, then another prompt	7	3
Edited .python-version	8	4
Local file removed and global version edited	9	5
PYENV_VERSION set	10	6

With the fix, fish behaves like the bash and zsh hooks. It reruns activate after a directory change, a version file change, or a PYENV_VERSION change, and skips it otherwise. On my machine, each skipped call saves about 250–290 ms per prompt.

🤖 Generated with Claude Code

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Summary by cubic

Fixes the fish prompt hook so it no longer runs pyenv activate --quiet before every prompt, restoring the mtime-based deduplication that already worked for bash and zsh.

Bug Fixes

• Fish does not run command substitution inside double quotes, so the old check always compared _PYENV_VH_MTIMES against the literal text and never matched.
• stat now runs into a local list, and both lists are compared via string join; stat still only runs when $PWD is unchanged.
• test/init.bats is synced to match the new hook output.

^{Written for commit 701c84d. Summary will update on new commits.}

[cubic-dev-ai]

All reported issues were addressed across 2 files

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