zshrc doesn't recognize custom bash functions - bash

Question

I recently moved from bash to zsh, and like most of people I had my custom bash aliases/functions to ease git and env sourcing operations. In particular there are 2 of them which doesn't work properly when run on zsh but work completely fine on bash.
export REPO_ROOT=/home/pablo/repos/my_repo
alias croot='cd $REPO_ROOT'
alias subroot='cd $REPO_ROOT/subrepo/subrepo_1/'
repcheckout(){
git checkout "$1"
if [ $(pwd) == $REPO_ROOT ]; then
subroot
else
croot
fi
git checkout "$1"
if [ $(pwd) == $REPO_ROOT ]; then
subroot
else
croot
fi
}
The idea is that I have a set of main_repo-submodule branches and when I checkout the main repo, I want to checkout the submodule in the corresponding branch, instead of doing:
$ git submodule update --init --recursive subrepo/subrepo_1
which checkouts the proper commit in the submodule but doesn't update that I switched to a certain local branch.
For the previous func, the error dropped by zsh when running
$ repcheckout my_cool_branch
is
M subrepo/subrepo_1/
Switched to branch 'my_cool_branch'
repcheckout:2: = not found
Later I have a setup.sh file that I source which goes as follows:
add2path() {
if ! echo ${!1} | egrep "(^|:)$2(:|\$)" > /dev/null ; then
declare -g $1="${!1}:$2"
export "$1"
fi
}
# GENERATED BINARY A
export BIN_A_HOME="$REPO_ROOT/bin_a"
add2path PATH "$BIN_A_HOME/bin"
Same with some generated python modules that are added to PYTHONPATH using the same add2path
Which drops the error:
add2path:1: bad substitution

Answer 1

Both functions use bashisms that aren't valid in zsh.
In repcheckout, the problem is using the == operator in a [ ] test -- the standard operator is =, but bash allows == as a synonym; zsh doesn't. I'd also recommend double-quoting both strings to avoid problems with weird characters in the path (and maybe using "$PWD" instead of $(pwd)):
if [ "$PWD" = "$REPO_ROOT" ]; then
In add2path, the problem is the indirect variable reference ${!1} in both the echo and declare commands. zsh also allows indirect variable references, but its syntax is completely different: ${(P)1}. You could probably make a cross-compatible version with eval, but that tends to cause weird bugs if you don't use it exactly right; I'd just rewrite the function as needed for zsh.
EDIT: If you want to use the same code under both bash and zsh, eval is probably better than trying to detect which shell you're in and using conditional code based on that. Here's a quick stab at writing a cross-shell compatible version:
if ! eval "echo \"\$$1\"" | egrep "(^|:)$2(:|\$)" > /dev/null ; then
eval "declare -g $1=\"\$$1:\$2\""
export "$1"
...
The quoting is ugly, but it should work ok as long as $1 contains a valid identifier; if it doesn't, the usual eval problems may rear their ugly heads.