git: go back to previous main branch detection logic

Fixes #9114

plugins/git/README.md

@@ -183,8 +183,8 @@ plugins=(... git)
 
 Following the recent push for removing racially-charged words from our technical vocabulary, the git plugin favors using
 a branch name other than `master`. In this case, we favor the shorter, neutral and descriptive term `main`. This means
-that any aliases and functions that previously used `master`, will use `main` if `master` doesn't exist. We do this via
-the function `git_main_branch`.
+that any aliases and functions that previously used `master`, will use `main` if that branch exists. We do this via the
+function `git_main_branch`.
 
 ### Deprecated aliases
 
@@ -209,12 +209,12 @@ These are aliases that have been removed, renamed, or otherwise modified in a wa
 ### Current
 
 | Command                | Description                                                                  |
-|:-----------------------|:---------------------------------------------------------------------------------------|
+|:-----------------------|:-----------------------------------------------------------------------------|
 | `grename <old> <new>`  | Rename `old` branch to `new`, including in origin remote                     |
 | current_branch         | Return the name of the current branch                                        |
 | git_current_user_name  | Returns the `user.name` config value                                         |
 | git_current_user_email | Returns the `user.email` config value                                        |
-| git_main_branch        | Returns the name of the main branch: from origin or from local branches, else 'master' |
+| git_main_branch        | Returns the name of the main branch: `main` if it exists, `master` otherwise |
 
 ### Work in Progress (WIP)
 

plugins/git/git.plugin.zsh

@@ -25,29 +25,13 @@ function work_in_progress() {
   fi
 }
 
-# Get the default 'main' branch: from origin, from local branches, or else just 'master'
+# Check if main exists and use instead of master
 function git_main_branch() {
-  # Get default branch from the origin remote
-  local branch
-  branch="${$(command git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null)#refs/remotes/origin/}"
-
-  if [[ -n "$branch" ]]; then
-    echo "$branch"
-    return
-  fi
-
-  # Look up list of local branches and return the first one that exists
-  local -a branches
-  branches=(${(@f)"$(command git for-each-ref --format='%(refname:short)' refs/heads 2>/dev/null)"})
-  for branch in master main; do
-    if (( ${branches[(Ie)$branch]} )); then
-      echo "$branch"
-      return
-    fi
-  done
-
+  if [[ -n "$(git branch --list main)" ]]; then
+    echo main
+  else
     echo master
-  return 1
+  fi
 }
 
 #