Z_A_USECOMP: recache subcommand not completing via shim mechanism

[HaleTom]

Summary

The Z_A_USECOMP=1 shim mechanism doesn't add recache to _zinit's tab-completable subcommands. The _zinit_shim approach of chaining _zinit_recache and _zinit has a fundamental issue: _zinit_recache uses _arguments which creates a nested _arguments context when called directly from the shim (bypassing _call_function).

Root cause

_zinit's completion defines subcommands in __zinit_commands() (a hardcoded list in the _zinit file). The recache subcommand is not in this list. The shim tries to work around this by calling both _zinit_recache and _zinit, but:

1. _zinit_recache's _arguments -C call, when invoked directly from the shim (not via _call_function), may conflict with the outer completion context.
2. _zinit still doesn't list recache in its subcommands, so the base completion never offers it.

Steps to reproduce

1. Load z-a-eval with Z_A_USECOMP=1:

   zinit atinit'Z_A_USECOMP=1' light-mode for NICHOLAS85/z-a-eval

2. Type zinit rec and press Tab
3. No completion for recache is offered

Expected behavior

zinit rec<TAB> should complete to zinit recache.

Suggested fix

Instead of (or in addition to) the shim mechanism, patch _zinit's __zinit_commands to include the recache subcommand. This can be done by sourcing the _zinit file (minus the final _zinit "$@" call) and injecting recache into the commands array:

# Source _zinit to define all functions (makes _zinit a real function, not autoload stub)
eval "$(head -n -1 "${ZINIT[BIN_DIR]}/_zinit")" 2>/dev/null
# Inject recache into __zinit_commands
eval "$(sed -n '/^__zinit_commands()/,/^} # \]\]\]$/p' "${ZINIT[BIN_DIR]}/_zinit" \
  | sed "/recently:Show plugins that changed recently/a\\    'recache:Regenerate eval cache (z-a-eval annex)'")"

Since _zinit becomes a real function (not an autoload stub), the autoload mechanism won't overwrite the patched __zinit_commands on first tab completion.

Environment

• Zsh 5.9+
• zinit (zdharma-continuum) latest
• z-a-eval main branch