dorothy, fs-realpath: detect when alpine uses busybox or coreutils an…

…d react accordingly

/ref https://github.com/bevry/dorothy/actions/runs/11337845512/job/31530095505#step:4:56

commands/dorothy

@@ -330,7 +330,7 @@ function dorothy_() (
 
 	# see [commands/is-alpine] for details
 	function __is_alpine {
-		test -f /etc/os-release && grep --quiet --ignore-case --regexp='ID=alpine' /etc/os-release 2>/dev/null;
+		test -f /etc/os-release && grep --quiet --ignore-case --regexp='ID=alpine' /etc/os-release 2>/dev/null
 	}
 
 	# see [commands/fs-realpath] for details
@@ -362,9 +362,11 @@ function dorothy_() (
 		if __command_exists -- grealpath; then
 			gnu_realpath='grealpath'
 		elif __command_exists -- realpath; then
-			if __is_mac || __is_alpine; then
-				# realpath on macos and alpine doesn't support any options, so missing --canonicalize-existing and --canonicalize-missing
-				# https://github.com/bevry/dorothy/actions/runs/11337594338/job/31529440618#step:4:36
+			if __is_mac; then
+				# usage: realpath [-q] [path ...]
+				fallback_realpath='realpath'
+			elif __is_alpine && test "$(realpath "$(type -P 'realpath')" || :)" = "$(type -P busybox || :)"; then
+				# Usage: realpath FILE...
 				fallback_realpath='realpath'
 			elif __is_linux; then
 				gnu_realpath='realpath'
@@ -373,9 +375,11 @@ function dorothy_() (
 		if __command_exists -- greadlink; then
 			gnu_readlink='greadlink'
 		elif __command_exists -- readlink; then
-			if __is_mac || __is_alpine; then
-				# readlink on macos and alpine doesn't support usual options, so missing --canonicalize-existing and --canonicalize-missing
-				# https://github.com/bevry/dorothy/actions/runs/11337683504/job/31529682952#step:4:36
+			if __is_mac; then
+				# usage: readlink [-fn] [file ...]
+				fallback_readlink='readlink'
+			elif __is_alpine && test "$(readlink -f "$(type -P 'readlink')" || :)" = "$(type -P busybox || :)"; then
+				# Usage: readlink [-fnv] FILE
 				fallback_readlink='readlink'
 			elif __is_linux; then
 				gnu_readlink='readlink'

commands/fs-realpath

@@ -85,14 +85,18 @@ function fs_realpath() (
 		local gnu_realpath
 		if __command_exists -- grealpath; then
 			gnu_realpath='grealpath'
-		elif __command_exists -- realpath && is-linux && ! is-alpine; then
-			# alpine realpath doesn't support any options, so missing --canonicalize-existing and --canonicalize-missing
-			# https://github.com/bevry/dorothy/actions/runs/11337594338/job/31529440618#step:4:36
-			# / # realpath --help
-			# BusyBox v1.36.1 (2024-06-10 07:11:47 UTC) multi-call binary.
-			# Usage: realpath FILE...
-			# Print absolute pathnames of FILEs
-			gnu_realpath='realpath'
+		elif __command_exists -- realpath; then
+			if is-mac; then
+				# usage: realpath [-q] [path ...]
+				return 45 # ENOTSUP 45 Operation not supported
+			elif is-alpine && test "$(realpath "$(type -P 'realpath')" || :)" = "$(type -P busybox || :)"; then
+				# Usage: realpath FILE...
+				return 45 # ENOTSUP 45 Operation not supported
+			elif is-linux; then
+				gnu_realpath='realpath'
+			else
+				return 45 # ENOTSUP 45 Operation not supported
+			fi
 		else
 			return 45 # ENOTSUP 45 Operation not supported
 		fi
@@ -148,17 +152,18 @@ function fs_realpath() (
 		local gnu_readlink
 		if __command_exists -- greadlink; then
 			gnu_readlink='greadlink'
-		elif __command_exists -- readlink && is-linux && ! is-alpine; then
-			# alpine readlink doesn't support any options, so missing --canonicalize-existing and --canonicalize-missing
-			# https://github.com/bevry/dorothy/actions/runs/11337683504/job/31529682952#step:4:36
-			# / # readlink --help
-			# BusyBox v1.36.1 (2024-06-10 07:11:47 UTC) multi-call binary.
-			# Usage: readlink [-fnv] FILE
-			# Display the value of a symlink
-			# -f	Canonicalize by following all symlinks
-			# -n	Don't add newline
-			# -v	Verbose
-			gnu_readlink='readlink'
+		elif __command_exists -- readlink; then
+			if is-mac; then
+				# usage: readlink [-fn] [file ...]
+				return 45 # ENOTSUP 45 Operation not supported
+			elif is-alpine && test "$(readlink -f "$(type -P 'readlink')" || :)" = "$(type -P busybox || :)"; then
+				# Usage: readlink [-fnv] FILE
+				return 45 # ENOTSUP 45 Operation not supported
+			elif is-linux; then
+				gnu_readlink='readlink'
+			else
+				return 45 # ENOTSUP 45 Operation not supported
+			fi
 		else
 			return 45 # ENOTSUP 45 Operation not supported
 		fi
@@ -207,8 +212,14 @@ function fs_realpath() (
 
 		local fallback_readlink
 		if __command_exists -- readlink; then
-			if is-mac || is-alpine; then
+			if is-mac; then
+				# usage: readlink [-fn] [file ...]
 				fallback_readlink='readlink'
+			elif is-alpine && test "$(readlink -f "$(type -P 'readlink')" || :)" = "$(type -P busybox || :)"; then
+				# Usage: readlink [-fnv] FILE
+				fallback_readlink='readlink'
+			else
+				return 45 # ENOTSUP 45 Operation not supported
 			fi
 		else
 			return 45 # ENOTSUP 45 Operation not supported
@@ -243,8 +254,14 @@ function fs_realpath() (
 
 		local fallback_realpath
 		if __command_exists -- realpath; then
-			if is-mac || is-alpine; then
+			if is-mac; then
+				# usage: realpath [-q] [path ...]
+				fallback_realpath='realpath'
+			elif is-alpine && test "$(realpath "$(type -P 'realpath')" || :)" = "$(type -P busybox || :)"; then
+				# Usage: realpath FILE...
 				fallback_realpath='realpath'
+			else
+				return 45 # ENOTSUP 45 Operation not supported
 			fi
 		else
 			return 45 # ENOTSUP 45 Operation not supported