minimal zsh completion (#20253)

Since zsh can load bash completion files natively, seems reasonable to just turn this on.
The only changes are to switch from `type -t` which zsh doesn't support to using `type`
with a regex and adding a new arm to the sourcing of the completions to allow it to work
for zsh as well as bash.

Could use more bash/dash/etc testing probably, but everything I've thought to try has
worked so far.

Notes:
* unit-test zsh support, fix issues
Specifically fixed word splitting in completion-test, use a different
method to apply sh emulation to zsh loaded bash completion, and fixed
an incompatibility in regex operator quoting requirements.

* compinit now ignores insecure directories
Completion isn't meant to be enabled in non-interactive environments, so
by default compinit will ask the user if they want to ignore insecure
directories or load them anyway.  To pass the spack unit tests in GH
actions, this prompt must be disabled, so ignore explicitly until a
better solution can be found.

* debug functions test also requires bash emulation
COMP_WORDS is a bash-ism that zsh doesn't natively support, turn on
emulation for just that section of tests to allow the comparison to
work.  Does not change the behavior of the functions themselves since
they are already pinned to sh emulation elsewhere.

* propagate change to .in file

* fix comment and update script based on .in

5 files changed, 74 insertions, 35 deletions

diff --git a/share/spack/bash/spack-completion.in b/share/spack/bash/spack-completion.in
index 80ba94ed87..9aa890ed02 100755
--- a/share/spack/bash/spack-completion.in
+++ b/share/spack/bash/spack-completion.in
@@ -37,6 +37,17 @@
 #
 # See `man bash` for more details.
 
+if test -n "${ZSH_VERSION:-}" ; then
+  if [[ "$(emulate)" = zsh ]] ; then
+    # ensure base completion support is enabled, ignore insecure directories
+    autoload -U +X compinit && compinit -i
+    # ensure bash compatible completion support is enabled
+    autoload -U +X bashcompinit && bashcompinit
+    emulate sh -c "source '$0:A'"
+    return # stop interpreting file
+  fi
+fi
+
 # Bash programmable completion for Spack
 _bash_completion_spack() {
     # In all following examples, let the cursor be denoted by brackets, i.e. []
@@ -117,7 +128,9 @@ _bash_completion_spack() {
     #_test_vars >> temp
 
     # Make sure function exists before calling it
-    if [[ "$(type -t $subfunction)" == "function" ]]
+    local rgx #this dance is necessary to cover bash and zsh regex
+    rgx="$subfunction.*function.* "
+    if [[ "$(type $subfunction 2>&1)" =~ $rgx ]]
     then
         $subfunction
         COMPREPLY=($(compgen -W "$SPACK_COMPREPLY" -- "$cur"))
diff --git a/share/spack/qa/completion-test.sh b/share/spack/qa/completion-test.sh
index 59a5181b98..64f07f69c4 100755
--- a/share/spack/qa/completion-test.sh
+++ b/share/spack/qa/completion-test.sh
@@ -31,13 +31,18 @@ title "Testing spack-completion.$_sp_shell with $_sp_shell"
 succeeds which spack
 
 title 'Testing all subcommands'
-while IFS= read -r line
+# read line into an array portably
+READ="read -ra line"
+if [ -n "${ZSH_VERSION:-}" ]; then
+  READ=(read -rA line)
+fi
+while IFS=' ' $READ
 do
     # Test that completion with no args works
-    succeeds _spack_completions ${line[*]} ''
+    succeeds _spack_completions "${line[@]}" ''
 
     # Test that completion with flags works
-    contains '-h --help' _spack_completions ${line[*]} -
+    contains '-h --help' _spack_completions "${line[@]}" -
 done <<- EOF
     $(spack commands --aliases --format=subcommands)
 EOF
@@ -58,32 +63,39 @@ contains 'hdf5' _spack_completions spack install -v ''
 # XFAIL: Fails for Python 2.6 because pkg_resources not found?
 #contains 'compilers.py' _spack_completions spack unit-test ''
 
-title 'Testing debugging functions'
-
-# This is a particularly tricky case that involves the following situation:
-#     `spack -d [] install `
-# Here, [] represents the cursor, which is in the middle of the line.
-# We should tab-complete optional flags for `spack`, not optional flags for
-# `spack install` or package names.
-COMP_LINE='spack -d  install '
-COMP_POINT=9
-COMP_WORDS=(spack -d install)
-COMP_CWORD=2
-COMP_KEY=9
-COMP_TYPE=64
-
-_bash_completion_spack
-contains "--all-help" echo "${COMPREPLY[@]}"
-
-contains "['spack', '-d', 'install', '']" _pretty_print COMP_WORDS[@]
-
-# Set the rest of the intermediate variables manually
-COMP_WORDS_NO_FLAGS=(spack install)
-COMP_CWORD_NO_FLAGS=1
-subfunction=_spack
-cur=
-
-list_options=true
-contains "'True'" _test_vars
-list_options=false
-contains "'False'" _test_vars
+_test_debug_functions() {
+    title 'Testing debugging functions'
+
+    if [ -n "${ZSH_VERSION:-}" ]; then
+        emulate -L sh
+    fi
+
+    # This is a particularly tricky case that involves the following situation:
+    #     `spack -d [] install `
+    # Here, [] represents the cursor, which is in the middle of the line.
+    # We should tab-complete optional flags for `spack`, not optional flags for
+    # `spack install` or package names.
+    COMP_LINE='spack -d  install '
+    COMP_POINT=9
+    COMP_WORDS=(spack -d install)
+    COMP_CWORD=2
+    COMP_KEY=9
+    COMP_TYPE=64
+
+    _bash_completion_spack
+    contains "--all-help" echo "${COMPREPLY[@]}"
+
+    contains "['spack', '-d', 'install', '']" _pretty_print COMP_WORDS[@]
+
+    # Set the rest of the intermediate variables manually
+    COMP_WORDS_NO_FLAGS=(spack install)
+    COMP_CWORD_NO_FLAGS=1
+    subfunction=_spack
+    cur=
+
+    list_options=true
+    contains "'True'" _test_vars
+    list_options=false
+    contains "'False'" _test_vars
+}
+_test_debug_functions
diff --git a/share/spack/qa/run-shell-tests b/share/spack/qa/run-shell-tests
index 9c5302ec89..310a824e42 100755
--- a/share/spack/qa/run-shell-tests
+++ b/share/spack/qa/run-shell-tests
@@ -43,6 +43,7 @@ fi
 
 # Run the test scripts for their output (these will print nicely)
 zsh  "$QA_DIR/setup-env-test.sh"
+zsh "$QA_DIR/completion-test.sh"
 dash "$QA_DIR/setup-env-test.sh"
 
 # Run fish tests
diff --git a/share/spack/setup-env.sh b/share/spack/setup-env.sh
index 5761d16362..7f648207e4 100755
--- a/share/spack/setup-env.sh
+++ b/share/spack/setup-env.sh
@@ -371,7 +371,7 @@ _sp_multi_pathadd MODULEPATH "$_sp_tcl_roots"
 
 # Add programmable tab completion for Bash
 #
-if [ "$_sp_shell" = bash ]; then
+if test "$_sp_shell" = bash || test -n "${ZSH_VERSION:-}"; then
     source $_sp_share_dir/spack-completion.bash
 fi
 
diff --git a/share/spack/spack-completion.bash b/share/spack/spack-completion.bash
index 1761fcb60d..0143d305ca 100755
--- a/share/spack/spack-completion.bash
+++ b/share/spack/spack-completion.bash
@@ -37,6 +37,17 @@
 #
 # See `man bash` for more details.
 
+if test -n "${ZSH_VERSION:-}" ; then
+  if [[ "$(emulate)" = zsh ]] ; then
+    # ensure base completion support is enabled, ignore insecure directories
+    autoload -U +X compinit && compinit -i
+    # ensure bash compatible completion support is enabled
+    autoload -U +X bashcompinit && bashcompinit
+    emulate sh -c "source '$0:A'"
+    return # stop interpreting file
+  fi
+fi
+
 # Bash programmable completion for Spack
 _bash_completion_spack() {
     # In all following examples, let the cursor be denoted by brackets, i.e. []
@@ -117,7 +128,9 @@ _bash_completion_spack() {
     #_test_vars >> temp
 
     # Make sure function exists before calling it
-    if [[ "$(type -t $subfunction)" == "function" ]]
+    local rgx #this dance is necessary to cover bash and zsh regex
+    rgx="$subfunction.*function.* "
+    if [[ "$(type $subfunction 2>&1)" =~ $rgx ]]
     then
         $subfunction
         COMPREPLY=($(compgen -W "$SPACK_COMPREPLY" -- "$cur"))