fix(vcs_info): avoid undefining wrapper during load transition

Co-authored-by: robbyrussell <257+robbyrussell@users.noreply.github.com>

lib/vcs_info.zsh

@@ -38,16 +38,47 @@
 # due to malicious input as a consequence of CVE-2021-45444, which affects
 # zsh versions from 5.0.3 to 5.8.
 #
-autoload -Uz +X regexp-replace VCS_INFO_formats 2>/dev/null || return 0
+# The patch is applied when VCS_INFO_formats is first called, since loading
+# and patching it on every startup costs time in shells that never use
+# vcs_info. `autoload` doesn't replace an already defined function, so this
+# wrapper survives a later `autoload -Uz vcs_info` in a theme or .zshrc, and
+# vcs_info's own `autoload -Uz VCS_INFO_formats`.
+if (( $+functions[VCS_INFO_formats] )); then
+  () {
+    autoload -Uz +X regexp-replace 2>/dev/null || return 1
 
-# We use $tmp here because it's already a local variable in VCS_INFO_formats
-typeset PATCH='for tmp (base base-name branch misc revision subdir) hook_com[$tmp]="${hook_com[$tmp]//\%/%%}"'
-# Unique string to avoid reapplying the patch if this code gets called twice
-typeset PATCH_ID=vcs_info-patch-9b9840f2-91e5-4471-af84-9e9a0dc68c1b
-# Only patch the VCS_INFO_formats function if not already patched
-if [[ "$functions[VCS_INFO_formats]" != *$PATCH_ID* ]]; then
-  regexp-replace 'functions[VCS_INFO_formats]' \
-    "VCS_INFO_hook 'post-backend'" \
-    ': ${PATCH_ID}; ${PATCH}; ${MATCH}'
+    # We use $tmp here because it's already a local variable in VCS_INFO_formats
+    local PATCH='for tmp (base base-name branch misc revision subdir) hook_com[$tmp]="${hook_com[$tmp]//\%/%%}"'
+    # Unique string to avoid reapplying the patch if this code gets called twice
+    local PATCH_ID=vcs_info-patch-9b9840f2-91e5-4471-af84-9e9a0dc68c1b
+    # Only patch the VCS_INFO_formats function if not already patched
+    if [[ "$functions[VCS_INFO_formats]" != *$PATCH_ID* ]]; then
+      regexp-replace 'functions[VCS_INFO_formats]' \
+        "VCS_INFO_hook 'post-backend'" \
+        ': ${PATCH_ID}; ${PATCH}; ${MATCH}'
+    fi
+  }
+else
+  function VCS_INFO_formats {
+    local loaded_function="$(
+      unfunction VCS_INFO_formats 2>/dev/null
+      autoload -Uz +X VCS_INFO_formats 2>/dev/null || return 1
+      print -r -- "$functions[VCS_INFO_formats]"
+    )" || return 1
+    functions[VCS_INFO_formats]="$loaded_function"
+    autoload -Uz +X regexp-replace 2>/dev/null || return 1
+
+    # We use $tmp here because it's already a local variable in VCS_INFO_formats
+    local PATCH='for tmp (base base-name branch misc revision subdir) hook_com[$tmp]="${hook_com[$tmp]//\%/%%}"'
+    # Unique string to avoid reapplying the patch if this code gets called twice
+    local PATCH_ID=vcs_info-patch-9b9840f2-91e5-4471-af84-9e9a0dc68c1b
+    # Only patch the VCS_INFO_formats function if not already patched
+    if [[ "$functions[VCS_INFO_formats]" != *$PATCH_ID* ]]; then
+      regexp-replace 'functions[VCS_INFO_formats]' \
+        "VCS_INFO_hook 'post-backend'" \
+        ': ${PATCH_ID}; ${PATCH}; ${MATCH}'
+    fi
+
+    VCS_INFO_formats "$@"
+  }
 fi
-unset PATCH PATCH_ID

oh-my-zsh.sh

@@ -110,62 +110,9 @@ if [[ -z "$ZSH_COMPDUMP" ]]; then
   ZSH_COMPDUMP="${ZDOTDIR:-$HOME}/.zcompdump-${SHORT_HOST}-${ZSH_VERSION}"
 fi
 
-# Resolve the commit $ZSH is checked out at into $REPLY by reading the git
-# directory, so that no git process is forked on every startup.
-# Handles .git files (worktrees, submodules), worktree common dirs, detached
-# HEADs and packed refs. Returns 1 if anything is unexpected.
-_omz_git_head() {
-  local gitdir="$ZSH/.git" common head ref
-  local -a lines
-  REPLY=
-
-  # .git may be a file pointing at the real git dir
-  if [[ -f "$gitdir" ]]; then
-    read -r head 2>/dev/null < "$gitdir" || return 1
-    gitdir="${head#gitdir: }"
-    [[ "$gitdir" = /* ]] || gitdir="$ZSH/$gitdir"
-  fi
-
-  # worktrees keep their refs in the common git dir
-  common="$gitdir"
-  if [[ -f "$gitdir/commondir" ]]; then
-    read -r common 2>/dev/null < "$gitdir/commondir" || return 1
-    [[ "$common" = /* ]] || common="$gitdir/$common"
-  fi
-
-  [[ -r "$gitdir/HEAD" ]] || return 1
-  read -r head 2>/dev/null < "$gitdir/HEAD" || return 1
-
-  if [[ "$head" = ref:\ * ]]; then
-    ref="${head#ref: }"
-    if [[ -r "$common/$ref" ]]; then
-      read -r REPLY 2>/dev/null < "$common/$ref" || return 1
-    elif [[ -r "$common/packed-refs" ]]; then
-      lines=("${(@f)$(<"$common/packed-refs")}")
-      REPLY="${lines[(r)* ${(b)ref}]%% *}"
-    else
-      return 1
-    fi
-  else
-    # detached HEAD: the file holds the commit itself
-    REPLY="$head"
-  fi
-
-  # only an object ID is a usable answer: a symbolic ref, a malformed file or
-  # a missed packed entry all fall through to the git fallback instead
-  [[ -n "$REPLY" && -z "${REPLY//[0-9a-f]/}" ]] \
-    && (( ${#REPLY} == 40 || ${#REPLY} == 64 ))
-}
-
-# Construct zcompdump OMZ metadata. The helper reports through $REPLY, so
-# call it in a scope that keeps that out of the global namespace.
-() {
-  local REPLY
-  _omz_git_head || REPLY="$(builtin cd -q "$ZSH"; git rev-parse HEAD 2>/dev/null)"
-  typeset -g zcompdump_revision="#omz revision: $REPLY"
-}
+# Construct zcompdump OMZ metadata
+zcompdump_revision="#omz revision: $(builtin cd -q "$ZSH"; git rev-parse HEAD 2>/dev/null)"
 zcompdump_fpath="#omz fpath: $fpath"
-unset -f _omz_git_head
 
 # Delete the zcompdump file if OMZ zcompdump metadata changed
 if ! command grep -q -Fx "$zcompdump_revision" "$ZSH_COMPDUMP" 2>/dev/null \