Support env -S/--split-string in shebangs (fixes #2105)

CHANGELOG.md

@@ -13,6 +13,7 @@
 - SC1072/SC1073 now respond to disable annotations, though ignoring parse errors
   is still purely cosmetic and does not allow ShellCheck to continue.
 - Improved error reporting for trailing tokens after ]/]] and compound commands
+- `#!/usr/bin/env -S shell` is now handled correctly
 
 ### Changed
 - Assignments are now parsed to spec, without leniency for leading $ or spaces

src/ShellCheck/Analytics.hs

@@ -546,9 +546,14 @@ indexOfSublists sub = f 0
 
 prop_checkShebangParameters1 = verifyTree checkShebangParameters "#!/usr/bin/env bash -x\necho cow"
 prop_checkShebangParameters2 = verifyNotTree checkShebangParameters "#! /bin/sh  -l "
+prop_checkShebangParameters3 = verifyNotTree checkShebangParameters "#!/usr/bin/env -S bash -x\necho cow"
+prop_checkShebangParameters4 = verifyNotTree checkShebangParameters "#!/usr/bin/env --split-string bash -x\necho cow"
 checkShebangParameters p (T_Annotation _ _ t) = checkShebangParameters p t
 checkShebangParameters _ (T_Script _ (T_Literal id sb) _) =
-    [makeComment ErrorC id 2096 "On most OS, shebangs can only specify a single parameter." | length (words sb) > 2]
+    [makeComment ErrorC id 2096 "On most OS, shebangs can only specify a single parameter." | isMultiWord]
+  where
+    isMultiWord = length (words sb) > 2 && not (sb `matches` re)
+    re = mkRegex "env +(-S|--split-string)"
 
 prop_checkShebang1 = verifyNotTree checkShebang "#!/usr/bin/env bash -x\necho cow"
 prop_checkShebang2 = verifyNotTree checkShebang "#! /bin/sh  -l "

src/ShellCheck/AnalyzerLib.hs

@@ -238,6 +238,8 @@ prop_determineShell5 = determineShellTest "#shellcheck shell=sh\nfoo" == Sh
 prop_determineShell6 = determineShellTest "#! /bin/sh" == Sh
 prop_determineShell7 = determineShellTest "#! /bin/ash" == Dash
 prop_determineShell8 = determineShellTest' (Just Ksh) "#!/bin/sh" == Sh
+prop_determineShell9 = determineShellTest "#!/bin/env -S dash -x" == Dash
+prop_determineShell10 = determineShellTest "#!/bin/env --split-string= dash -x" == Dash
 
 determineShellTest = determineShellTest' Nothing
 determineShellTest' fallbackShell = determineShell fallbackShell . fromJust . prRoot . pScript
@@ -256,10 +258,12 @@ determineShell fallbackShell t = fromMaybe Bash $
 executableFromShebang :: String -> String
 executableFromShebang = shellFor
   where
-    shellFor s | "/env " `isInfixOf` s = headOrDefault "" (drop 1 $ words s)
+    shellFor s | "/env " `isInfixOf` s = fromMaybe "" $ do
+        [flag, shell] <- matchRegex re s
+        return shell
     shellFor s | ' ' `elem` s = shellFor $ takeWhile (/= ' ') s
     shellFor s = reverse . takeWhile (/= '/') . reverse $ s
-
+    re = mkRegex "/env +(-S|--split-string=?)? *([^ ]*)"
 
 
 -- Given a root node, make a map from Id to parent Token.