FINALLY fix the weird cases for zsh/read builtin (particularly around reading one character from tty/pipe/file); also gave a --force-user-input flag in case you want to require user input on a yn prompt

zsh/lib/utils/io.zsh

@@ -33,7 +33,7 @@ WARNING() {  # warning-level messages; not errors
 }
 
 DEBUG() {  # helpful during development or (sparingly) to help others' development
-	[[ $SCWRYPTS_LOG_LEVEL -gt 4 ]] \
+	[[ $SCWRYPTS_LOG_LEVEL -ge 4 ]] \
 		&& PREFIX="DEBUG    ℹ" COLOR=$__WHITE          PRINT "$@"
 }
 
@@ -82,23 +82,10 @@ source "${0:a:h}/io.usage.zsh"
 ### facilitate user prompt and input ################################
 #####################################################################
 
-Yn() {  # ask a yes-or-no question (default yes)
-	PROMPT "$@ [Yn]"
-	[ $CI ] && { echo y >&2; return 0; }
-	[ $__SCWRYPTS_YES ] && [[ $__SCWRYPTS_YES -eq 1 ]] && { echo y; return 0; }
-
-	local Yn; READ -k Yn; echo >&2
-	[[ $Yn =~ [nN] ]] && return 1 || return 0
-}
-
-yN() {  # ask a yes-or-no question (default no)
-	PROMPT "$@ [yN]"
-	[ $CI ] && { echo y >&2; return 0; }
-	[ $__SCWRYPTS_YES ] && [[ $__SCWRYPTS_YES -eq 1 ]] && { echo y; return 0; }
-
-	local yN; READ -k yN; echo >&2
-	[[ $yN =~ [yY] ]] && return 0 || return 1
-}
+# yes/no prompts   && = yes (exit code 0)
+#                  || = no  (exit code 1)
+Yn() { [[ ! $(READ_YN $@ '[Yn]') =~ [nN] ]]; }  # default 'yes'
+yN() { [[   $(READ_YN $@ '[yN]') =~ [yY] ]]; }  # default 'no'
 
 INPUT() {  # read a single line of user input
 	PROMPT "${@:2}"
@@ -159,12 +146,85 @@ GETSUDO() {
 		|| { ERROR 'failed :c'; return 1; }
 }
 
-
 READ()  {
-	[ $CI ] && {
-		WARNING 'currently in CI, skipping READ'
-		return 0
-	}
-	read $@ </dev/tty
+	[ $CI ] && [ -t 0 ] \
+		&& FAIL 42 'currently in CI, but attempting interactive read; aborting'
+
+	local FORCE_USER_INPUT=false
+	local ARGS=()
+
+	while [[ $# -gt 0 ]]
+	do
+		case $1 in
+			--force-user-input ) FORCE_USER_INPUT=true ;;
+			-k )
+				ARGS+=($1)
+				;;
+			* ) ARGS+=($1) ;;
+		esac
+		shift 1
+	done
+
+	while read -k -t 0; do :; done;  # flush user stdin
+
+	case $FORCE_USER_INPUT in
+		true  )
+			read ${PREARGS[@]} ${ARGS[@]} $@ </dev/tty
+			;;
+		false )
+			[ -t 0 ] || ARGS=(-u 0 ${ARGS[@]})
+			read ${ARGS[@]} $@
+			;;
+	esac
 }
 
+READ_YN() {  # yes/no read is suprisingly tricky
+	local FORCE_USER_INPUT=false
+	local USERPROMPT=()
+	local READ_ARGS=()
+
+	while [[ $# -gt 0 ]]
+	do
+		case $1 in
+			--force-user-input )
+				# overrides 'scwrypts -y' and stdin pipe but not CI
+				FORCE_USER_INPUT=true
+				READ_ARGS+=($1)
+				;;
+			* ) USERPROMPT+=($1) ;;
+		esac
+		shift 1
+	done
+
+	##########################################
+
+	local SKIP_USER_INPUT=false
+
+	[ $CI ] \
+		&& SKIP_USER_INPUT=true
+
+	[ $__SCWRYPTS_YES ] && [[ $__SCWRYPTS_YES -eq 1 ]] && [[ $FORCE_USER_INPUT =~ false ]] \
+		&& SKIP_USER_INPUT=true
+
+	##########################################
+
+	local yn
+	PROMPT "${USERPROMPT[@]}"
+
+	case $SKIP_USER_INPUT in
+		true ) yn=y ;;
+		false )
+			[[ $FORCE_USER_INPUT =~ true ]] && [[ $SCWRYPTS_LOG_LEVEL -lt 1 ]] \
+				&& echo -n "${USERPROMPT[@]} : " >&2
+
+			READ ${READ_ARGS[@]} -s -k yn
+
+			[[ $FORCE_USER_INPUT =~ true ]] && [[ $SCWRYPTS_LOG_LEVEL -lt 1 ]] \
+				&& echo $yn >&2
+			;;
+	esac
+
+	[[ $SCWRYPTS_LOG_LEVEL -ge 1 ]] && echo $yn >&2
+
+	echo $yn
+}