When pulling a repo, fetch first, to check for updates

pkg/omf/functions/repo/omf.repo.pull.fish

 function omf.repo.pull
 
   if test (count $argv) -eq 0
-    echo (omf::err)"Argument of omf.repo.pull is the repo path."(omf::off)
+    echo (omf::err)"omf.repo.pull takes a repository path as an argument."(omf::off) 1>&2
     return $OMF_MISSING_ARG
   end
 
   set -l repo_dir $argv[1]
 
-  function omf.repo.git -V repo_dir
-    command git --git-dir "$repo_dir"/.git --work-tree "$repo_dir" $argv
-  end
-
-  function omf.repo.git.stash -V repo_dir
-    command git -C "$repo_dir" stash $argv
+  function __omf.repo.git -V repo_dir
+    command git -C "$repo_dir" $argv
   end
 
   set -l remote origin
-  if test (omf.repo.git config --get remote.upstream.url)
+  if test (__omf.repo.git config --get remote.upstream.url)
     set remote upstream
   end
 
-  set initial_branch (omf.repo.git symbolic-ref -q --short HEAD);
-    or return $OMF_UNKNOWN_ERR
-  set initial_revision (omf.repo.git rev-parse -q --verify HEAD);
-    or return $OMF_UNKNOWN_ERR
+  set initial_branch (__omf.repo.git symbolic-ref -q --short HEAD);
+    or return 1
+  set initial_revision (__omf.repo.git rev-parse -q --verify HEAD);
+    or return 1
+
+  # the refspec ensures that '$remote/master' gets updated
+  set -l refspec "refs/heads/master:refs/remotes/$remote/master"
+  __omf.repo.git fetch --quiet $remote $refspec;
+    or return 1
+
+  if test (__omf.repo.git rev-list --count master...FETCH_HEAD) -eq 0
+    return 2
+  end
 
-  if not omf.repo.git diff --quiet
+  if not __omf.repo.git diff --quiet
     echo (omf::em)"Stashing your changes:"(omf::off)
-    omf.repo.git status --short --untracked-files
-    omf.repo.git.stash save --include-untracked --quiet;
+    __omf.repo.git status --short --untracked-files
+    __omf.repo.git stash save --include-untracked --quiet;
       and set stashed
   end
 
   if test "$initial_branch" != master
-    omf.repo.git checkout master --quiet
+    __omf.repo.git checkout master --quiet
   end
 
-  set -l refspec "refs/heads/master:refs/remotes/$remote/master"
-
-  # the refspec ensures that '$remote/master' gets updated
-  if not omf.repo.git pull --ff-only --quiet $remote $refspec
-    omf.repo.git checkout $initial_branch
-    omf.repo.git reset --hard $initial_revision
-    set -q stashed; and omf.repo.git.stash pop
+  if not __omf.repo.git merge --ff-only --quiet FETCH_HEAD
+    __omf.repo.git checkout $initial_branch
+    __omf.repo.git reset --hard $initial_revision
+    set -q stashed; and __omf.repo.git stash pop
+    return 1
   end
 
   if test "$initial_branch" != master
-    omf.repo.git checkout $initial_branch --quiet
+    __omf.repo.git checkout $initial_branch --quiet
   end
 
   if set -q stashed
-    omf.repo.git.stash pop --quiet
+    __omf.repo.git stash pop --quiet
 
     echo (omf::em)"Restored your changes:"(omf::off)
-    command git -C "$repo_dir" status --short --untracked-files
+    __omf.repo.git status --short --untracked-files
   end
 
-  functions -e omf.repo.git{,.stash}
   return 0
 end