fix: Add support for 'vi' if 'ed' isn't installed (#53)

* As a full text editor is useful for writing the complicated multi-line
  patches into the 'activate' script, fall back to using 'vi' if 'ed' is
  not installed.
* Note that 'ed' or 'vi' works in the README.

Author: matthewfeickert

README.md

@@ -182,7 +182,7 @@ Required-by: cabinetry, coffea, servicex, uproot_browser
 
 A full listing of all programs used outside of Bash shell builtins are:
 * `cat`
-* `ed`
+* `ed` or `vi`
 * `find`
 * `readlink`
 * `sed`

cvmfs-venv.sh

@@ -157,6 +157,18 @@ fi
 unset _setup_command
 unset _do_setup_atlas
 
+# determine text editor to use for complicated edits to the activate script
+if [ -x "$(command -v ed)" ]; then
+    # default to using 'ed'
+    _text_editor="ed"
+elif [ -x "$(command -v vi)" ]; then
+    # fall back to 'vi'
+    _text_editor="vi"
+else
+    echo "ERROR: Neither 'ed' nor 'vi' is installed. Please install one of them."
+    exit 1
+fi
+
 _venv_name="${1:-venv}"
 if [ ! -d "${_venv_name}" ]; then
     printf "# Creating new Python virtual environment '%s'\n" "${_venv_name}"
@@ -289,53 +301,118 @@ EOT
     # block and inject the PYTHONPATH if statement block directly after it
     # (2 lines later).
     _RECOVER_OLD_PYTHONPATH_LINE="$(($(sed -n '\|unset _OLD_VIRTUAL_PYTHONHOME|=' "${_venv_full_path}"/bin/activate) + 2))"
-    ed --silent "${_venv_full_path}/bin/activate" <<EOF
+    # FIXME: Make a cleaner implimentation
+    if [ "${_text_editor}" == "ed" ]; then
+        ed --silent "${_venv_full_path}/bin/activate" <<EOF
+${_RECOVER_OLD_PYTHONPATH_LINE}i
+${_RECOVER_OLD_PYTHONPATH}
+.
+wq
+EOF
+    else
+        # only supporting vi so don't need to check
+        _vi_script=$(mktemp)
+        cat <<EOF > "${_vi_script}"
 ${_RECOVER_OLD_PYTHONPATH_LINE}i
 ${_RECOVER_OLD_PYTHONPATH}
 .
 wq
 EOF
+        vi -es "${_venv_full_path}/bin/activate" < "${_vi_script}"
+    fi
 
     # Find the line number of the last line in deactivate's PYTHONHOME reset
     # if statement block and inject the PYTHONPATH reset if statement block directly
     # after it (2 lines later).
     _SET_PYTHONPATH_INSERT_LINE="$(($(sed -n '\|    unset PYTHONHOME|=' "${_venv_full_path}"/bin/activate) + 2))"
-    ed --silent "${_venv_full_path}/bin/activate" <<EOF
+    # FIXME: Make a cleaner implimentation
+    if [ "${_text_editor}" == "ed" ]; then
+        ed --silent "${_venv_full_path}/bin/activate" <<EOF
 ${_SET_PYTHONPATH_INSERT_LINE}i
 ${_SET_PYTHONPATH}
 .
 wq
 EOF
+    else
+        # only supporting vi so don't need to check
+        _vi_script=$(mktemp)
+        cat <<EOF > "${_vi_script}"
+${_SET_PYTHONPATH_INSERT_LINE}i
+${_SET_PYTHONPATH}
+.
+wq
+EOF
+        vi -es "${_venv_full_path}/bin/activate" < "${_vi_script}"
+    fi
 
     # Find the line number of the deactivate function and inject the cvmfs-venv-rebase directly after it
     # (1 line later).
     _RUN_REBASE_LINE="$(($(sed -n '\|deactivate ()|=' "${_venv_full_path}"/bin/activate) + 1))"
-    ed --silent "${_venv_full_path}/bin/activate" <<EOF
+    # FIXME: Make a cleaner implimentation
+    if [ "${_text_editor}" == "ed" ]; then
+        ed --silent "${_venv_full_path}/bin/activate" <<EOF
 ${_RUN_REBASE_LINE}i
 ${_RUN_REBASE}
 .
 wq
 EOF
+    else
+        # only supporting vi so don't need to check
+        _vi_script=$(mktemp)
+        cat <<EOF > "${_vi_script}"
+${_RUN_REBASE_LINE}i
+${_RUN_REBASE}
+.
+wq
+EOF
+        vi -es "${_venv_full_path}/bin/activate" < "${_vi_script}"
+    fi
 
     # Find the line number of the unset -f deactivate line in deactivate's destructive unset
     # and inject the cvmfs-venv-rebase reset directly after it (1 line later).
     _DESCTRUCTIVE_UNSET_LINE="$(($(sed -n '\|unset -f deactivate|=' "${_venv_full_path}"/bin/activate) + 1))"
-    ed --silent "${_venv_full_path}/bin/activate" <<EOF
+    # FIXME: Make a cleaner implimentation
+    if [ "${_text_editor}" == "ed" ]; then
+        ed --silent "${_venv_full_path}/bin/activate" <<EOF
+${_DESCTRUCTIVE_UNSET_LINE}i
+${_DESCTRUCTIVE_UNSET}
+.
+wq
+EOF
+    else
+        # only supporting vi so don't need to check
+        _vi_script=$(mktemp)
+        cat <<EOF > "${_vi_script}"
 ${_DESCTRUCTIVE_UNSET_LINE}i
 ${_DESCTRUCTIVE_UNSET}
 .
 wq
 EOF
+        vi -es "${_venv_full_path}/bin/activate" < "${_vi_script}"
+    fi
 
     # Find the line number of the unset -f cvmfs-venv-rebase line in deactivate's destructive unset
     # and inject the cvmfs-venv-rebase function directly after it (4 lines later).
     _CVMFS_VENV_REBASE_LINE="$(($(sed -n '\|unset -f cvmfs-venv-rebase|=' "${_venv_full_path}"/bin/activate) + 4))"
-    ed --silent "${_venv_full_path}/bin/activate" <<EOF
+    # FIXME: Make a cleaner implimentation
+    if [ "${_text_editor}" == "ed" ]; then
+        ed --silent "${_venv_full_path}/bin/activate" <<EOF
 ${_CVMFS_VENV_REBASE_LINE}i
 ${_CVMFS_VENV_REBASE}
 .
 wq
 EOF
+    else
+        # only supporting vi so don't need to check
+        _vi_script=$(mktemp)
+        cat <<EOF > "${_vi_script}"
+${_CVMFS_VENV_REBASE_LINE}i
+${_CVMFS_VENV_REBASE}
+.
+wq
+EOF
+        vi -es "${_venv_full_path}/bin/activate" < "${_vi_script}"
+    fi
 
 unset _venv_full_path
 
@@ -380,3 +457,4 @@ unset _return_break
 unset _no_system_site_packages
 unset _no_update
 unset _no_uv
+unset _text_editor