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lib/vcs_info.zsh

@@ -38,47 +38,16 @@
 # due to malicious input as a consequence of CVE-2021-45444, which affects
 # zsh versions from 5.0.3 to 5.8.
 #
-# 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
+autoload -Uz +X regexp-replace VCS_INFO_formats 2>/dev/null || return 0
 
-    # 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}; ${MATCH}'
-    fi
-
-    VCS_INFO_formats "$@"
-  }
+# 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}'
 fi
+unset PATCH PATCH_ID

oh-my-zsh.sh

@@ -110,9 +110,53 @@ 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
+
+  # detached HEAD: the file holds the commit itself
+  [[ "$head" = ref:\ * ]] || { REPLY="$head"; return 0 }
+
+  ref="${head#ref: }"
+  if [[ -r "$common/$ref" ]]; then
+    read -r REPLY 2>/dev/null < "$common/$ref" || return 1
+    [[ "$REPLY" != ref:\ * ]] || return 1
+    return 0
+  fi
+
+  [[ -r "$common/packed-refs" ]] || return 1
+  lines=("${(@f)$(<"$common/packed-refs")}")
+  REPLY="${lines[(r)* ${(b)ref}]%% *}"
+  [[ -n "$REPLY" ]]
+}
+
 # Construct zcompdump OMZ metadata
-zcompdump_revision="#omz revision: $(builtin cd -q "$ZSH"; git rev-parse HEAD 2>/dev/null)"
+_omz_git_head || REPLY="$(builtin cd -q "$ZSH"; git rev-parse HEAD 2>/dev/null)"
+zcompdump_revision="#omz revision: $REPLY"
 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 \