make busybox sh Dash-like

src/ShellCheck/Analytics.hs

@@ -1204,6 +1204,7 @@ checkNumberComparisons params (TC_Binary id typ op lhs rhs) = do
             case shellType params of
                 Sh -> return ()  -- These are unsupported and will be caught by bashism checks.
                 Dash -> err id 2073 $ "Escape \\" ++ op ++ " to prevent it redirecting."
+                BusyboxSh -> err id 2073 $ "Escape \\" ++ op ++ " to prevent it redirecting."
                 _ -> err id 2073 $ "Escape \\" ++ op ++ " to prevent it redirecting (or switch to [[ .. ]])."
 
     when (op `elem` arithmeticBinaryTestOps) $ do
@@ -2782,6 +2783,7 @@ checkFunctionDeclarations params
             when (hasKeyword && hasParens) $
                 err id 2111 "ksh does not allow 'function' keyword and '()' at the same time."
         Dash -> forSh
+        BusyboxSh -> forSh
         Sh   -> forSh
 
     where
@@ -4044,7 +4046,8 @@ prop_checkModifiedArithmeticInRedirection3 = verifyNot checkModifiedArithmeticIn
 prop_checkModifiedArithmeticInRedirection4 = verify checkModifiedArithmeticInRedirection "cat <<< $((i++))"
 prop_checkModifiedArithmeticInRedirection5 = verify checkModifiedArithmeticInRedirection "cat << foo\n$((i++))\nfoo\n"
 prop_checkModifiedArithmeticInRedirection6 = verifyNot checkModifiedArithmeticInRedirection "#!/bin/dash\nls > $((i=i+1))"
-checkModifiedArithmeticInRedirection params t = unless (shellType params == Dash) $
+prop_checkModifiedArithmeticInRedirection7 = verifyNot checkModifiedArithmeticInRedirection "#!/bin/busybox sh\ncat << foo\n$((i++))\nfoo\n"
+checkModifiedArithmeticInRedirection params t = unless (shellType params == Dash || shellType params == BusyboxSh) $
     case t of
         T_Redirecting _ redirs (T_SimpleCommand _ _ (_:_)) -> mapM_ checkRedirs redirs
         _ -> return ()
@@ -4356,6 +4359,7 @@ checkEqualsInCommand params originalToken =
             Bash -> errWithFix id 2277 "Use BASH_ARGV0 to assign to $0 in bash (or use [ ] to compare)." bashfix
             Ksh -> err id 2278 "$0 can't be assigned in Ksh (but it does reflect the current function)."
             Dash -> err id 2279 "$0 can't be assigned in Dash. This becomes a command name."
+            BusyboxSh -> err id 2279 "$0 can't be assigned in Busybox Ash. This becomes a command name."
             _ -> err id 2280 "$0 can't be assigned this way, and there is no portable alternative."
     leadingNumberMsg id =
         err id 2282 "Variable names can't start with numbers, so this is interpreted as a command."

src/ShellCheck/AnalyzerLib.hs

@@ -206,18 +206,21 @@ makeParameters spec = params
             case shellType params of
                 Bash -> isOptionSet "lastpipe" root
                 Dash -> False
+                BusyboxSh -> False
                 Sh   -> False
                 Ksh  -> True,
         hasInheritErrexit =
             case shellType params of
                 Bash -> isOptionSet "inherit_errexit" root
                 Dash -> True
+                BusyboxSh -> True
                 Sh   -> True
                 Ksh  -> False,
         hasPipefail =
             case shellType params of
                 Bash -> isOptionSet "pipefail" root
                 Dash -> True
+                BusyboxSh -> isOptionSet "pipefail" root
                 Sh   -> True
                 Ksh  -> isOptionSet "pipefail" root,
         shellTypeSpecified = isJust (asShellType spec) || isJust (asFallbackShell spec),
@@ -899,6 +902,7 @@ isBashLike params =
         Bash -> True
         Ksh -> True
         Dash -> False
+        BusyboxSh -> False
         Sh -> False
 
 isTrueAssignmentSource c =

src/ShellCheck/Checks/Commands.hs

@@ -930,7 +930,7 @@ prop_checkTimedCommand2 = verify checkTimedCommand "#!/bin/dash\ntime ( foo; bar
 prop_checkTimedCommand3 = verifyNot checkTimedCommand "#!/bin/sh\ntime sleep 1"
 checkTimedCommand = CommandCheck (Exactly "time") f where
     f (T_SimpleCommand _ _ (c:args@(_:_))) =
-        whenShell [Sh, Dash] $ do
+        whenShell [Sh, Dash, BusyboxSh] $ do
             let cmd = last args -- "time" is parsed with a command as argument
             when (isPiped cmd) $
                 warn (getId c) 2176 "'time' is undefined for pipelines. time single stage or bash -c instead."
@@ -954,7 +954,7 @@ checkTimedCommand = CommandCheck (Exactly "time") f where
 prop_checkLocalScope1 = verify checkLocalScope "local foo=3"
 prop_checkLocalScope2 = verifyNot checkLocalScope "f() { local foo=3; }"
 checkLocalScope = CommandCheck (Exactly "local") $ \t ->
-    whenShell [Bash, Dash] $ do -- Ksh allows it, Sh doesn't support local
+    whenShell [Bash, Dash, BusyboxSh] $ do -- Ksh allows it, Sh doesn't support local
         path <- getPathM t
         unless (any isFunctionLike path) $
             err (getId $ getCommandTokenOrThis t) 2168 "'local' is only valid in functions."

src/ShellCheck/Checks/ShellSupport.hs

@@ -76,7 +76,7 @@ verifyNot c s = producesComments (testChecker c) s == Just False
 prop_checkForDecimals1 = verify checkForDecimals "((3.14*c))"
 prop_checkForDecimals2 = verify checkForDecimals "foo[1.2]=bar"
 prop_checkForDecimals3 = verifyNot checkForDecimals "declare -A foo; foo[1.2]=bar"
-checkForDecimals = ForShell [Sh, Dash, Bash] f
+checkForDecimals = ForShell [Sh, Dash, BusyboxSh, Bash] f
   where
     f t@(TA_Expansion id _) = sequence_ $ do
         str <- getLiteralString t
@@ -196,14 +196,16 @@ prop_checkBashisms101 = verify checkBashisms "read"
 prop_checkBashisms102 = verifyNot checkBashisms "read -r foo"
 prop_checkBashisms103 = verifyNot checkBashisms "read foo"
 prop_checkBashisms104 = verifyNot checkBashisms "read ''"
-checkBashisms = ForShell [Sh, Dash] $ \t -> do
+prop_checkBashisms105 = verifyNot checkBashisms "#!/bin/busybox sh\nset -o pipefail"
+checkBashisms = ForShell [Sh, Dash, BusyboxSh] $ \t -> do
     params <- ask
     kludge params t
  where
   -- This code was copy-pasted from Analytics where params was a variable
   kludge params = bashism
    where
-    isDash = shellType params == Dash
+    isBusyboxSh = shellType params == BusyboxSh
+    isDash = shellType params == Dash || isBusyboxSh
     warnMsg id code s =
         if isDash
         then err  id code $ "In dash, " ++ s ++ " not supported."
@@ -590,7 +592,7 @@ checkPS1Assignments = ForShell [Bash] f
 
 prop_checkMultipleBangs1 = verify checkMultipleBangs "! ! true"
 prop_checkMultipleBangs2 = verifyNot checkMultipleBangs "! true"
-checkMultipleBangs = ForShell [Dash, Sh] f
+checkMultipleBangs = ForShell [Dash, BusyboxSh, Sh] f
   where
     f token = case token of
         T_Banged id (T_Banged _ _) ->
@@ -601,7 +603,7 @@ checkMultipleBangs = ForShell [Dash, Sh] f
 prop_checkBangAfterPipe1 = verify checkBangAfterPipe "true | ! true"
 prop_checkBangAfterPipe2 = verifyNot checkBangAfterPipe "true | ( ! true )"
 prop_checkBangAfterPipe3 = verifyNot checkBangAfterPipe "! ! true | true"
-checkBangAfterPipe = ForShell [Dash, Sh, Bash] f
+checkBangAfterPipe = ForShell [Dash, BusyboxSh, Sh, Bash] f
   where
     f token = case token of
         T_Pipeline _ _ cmds -> mapM_ check cmds