zsh: git: do not fail when aliases are undefined

functions/git.zsh

@@ -74,3 +74,50 @@ compdef "__git_completion_wrapper __git_branch_names" git-diff-branch
 function git-show-changes(){
   git log --reverse HEAD^..
 }
+
+# oh-my-zsh has some aliases which we might want to override
+# with functions
+function _disable_alias() {
+  [[ -n $(alias "$1") ]] && unalias "$1"
+
+}
+
+_disable_alias gco
+function gco() {
+    if [[ "$#" -ge 1 ]]; then
+        g checkout $@
+    elif [[ "$#" -eq 0 ]]; then
+        g checkout $(gb | fzf)
+    fi
+
+}
+
+
+_disable_alias gcor
+function gcor() {
+    if [[ "$#" -ge 1 ]]; then
+        g checkout $@
+    elif [[ "$#" -eq 0 ]]; then
+        g checkout --track $(gbr | fzf)
+    fi
+
+}
+
+_disable_alias gbd
+function gbd() {
+    if [[ "$#" -ge 1 ]]; then
+        g branch -d $@
+    elif [[ "$#" -eq 0 ]]; then
+        g branch -d $(gb | fzf -m)
+    fi
+}
+
+
+_disable_alias gbD
+function gbD() {
+    if [[ "$#" -ge 1 ]]; then
+        g branch -D $@
+    elif [[ "$#" -eq 0 ]]; then
+        g branch -D $(gb | fzf -m)
+    fi
+}