Rewrote catastrophic rm detection, now simpler and more robust.

ShellCheck/Analytics.hs

@@ -2618,46 +2618,50 @@ checkFunctionDeclarations params
 checkFunctionDeclarations _ _ = return ()
 
 
--- This is a lot of code for little gain. Consider whether it's worth it.
 prop_checkCatastrophicRm1 = verify checkCatastrophicRm "rm -r $1/$2"
-prop_checkCatastrophicRm2 = verify checkCatastrophicRm "foo=$(echo bar); rm -r /home/$foo"
-prop_checkCatastrophicRm3 = verify checkCatastrophicRm "foo=/home; user=$(whoami); rm -r \"$foo/$user\""
-prop_checkCatastrophicRm4 = verifyNot checkCatastrophicRm "foo=/home; user=cow; rm -r \"$foo/$user\""
-prop_checkCatastrophicRm5 = verifyNot checkCatastrophicRm "user=$(whoami); rm -r /home/${user:?Nope}"
+prop_checkCatastrophicRm2 = verify checkCatastrophicRm "rm -r /home/$foo"
+prop_checkCatastrophicRm3 = verifyNot checkCatastrophicRm "rm -r /home/${USER:?}/*"
+prop_checkCatastrophicRm4 = verify checkCatastrophicRm "rm -fr /home/$(whoami)/*"
+prop_checkCatastrophicRm5 = verifyNot checkCatastrophicRm "rm -r /home/${USER:-thing}/*"
 prop_checkCatastrophicRm6 = verify checkCatastrophicRm "rm --recursive /etc/*$config*"
-prop_checkCatastrophicRm7 = verifyNot checkCatastrophicRm "var=$(cmd); if [ -n \"$var\" ]; then rm -r /etc/$var/*; fi"
 prop_checkCatastrophicRm8 = verify checkCatastrophicRm "rm -rf /home"
 prop_checkCatastrophicRm9 = verifyNot checkCatastrophicRm "rm -rf -- /home"
+prop_checkCatastrophicRmA = verify checkCatastrophicRm "rm -rf /usr /lib/nvidia-current/xorg/xorg"
+prop_checkCatastrophicRmB = verify checkCatastrophicRm "rm -rf \"$STEAMROOT/\"*"
 checkCatastrophicRm params t@(T_SimpleCommand id _ tokens) | t `isCommand` "rm" =
     when (any isRecursiveFlag simpleArgs) $
         mapM_ checkWord tokens
   where
-    -- This ugly hack is based on the fact that ids generally increase
-    relevantMap (Id n) = liftM snd . listToMaybe . dropWhile (\(Id x, _) ->  x > n) $ flowMapR
-    flowMapR = reverse $ (\x -> zip (scanl getScopeId (Id 0) x) (scanl addNulls defaultMap x)) $ variableFlow params
     simpleArgs = deadSimple t
-    defaultMap = Map.fromList (map (\x -> (x, Nothing)) variablesWithoutSpaces)
 
     checkWord token =
         case getLiteralString token of
             Just str ->
                 when (notElem "--" simpleArgs && (fixPath str `elem` importantPaths)) $
-                    info (getId token) 2114 "Obligatory typo warning. Use 'rm --' to disable this message."
+                    warn (getId token) 2114 "Warning: deletes a system directory. Use 'rm --' to disable this message."
             Nothing ->
                 checkWord' token
 
     checkWord' token = fromMaybe (return ()) $ do
-        m <- relevantMap id
-        filename <- combine m token
+        filename <- getPotentialPath token
         let path = fixPath filename
         return . when (path `elem` importantPaths) $
-            warn (getId token) 2115 $ "Make sure this never accidentally expands to '" ++ path ++ "'."
+            warn (getId token) 2115 $ "Use \"${var:?}\" to ensure this never expands to " ++ path ++ " ."
 
     fixPath filename =
         let normalized = skipRepeating '/' . skipRepeating '*' $ filename in
             if normalized == "/" then normalized else stripTrailing '/' normalized
 
-    unnullable = all isVariableChar . concat . deadSimple
+    getPotentialPath = getLiteralStringExt f
+      where
+        f (T_Glob _ str) = return str
+        f (T_DollarBraced _ word) =
+            let var = onlyLiteralString word in
+                if any (flip isInfixOf var) [":?", ":-", ":="]
+                then Nothing
+                else return ""
+        f _ = return ""
+
     isRecursiveFlag "--recursive" = True
     isRecursiveFlag ('-':'-':_) = False
     isRecursiveFlag ('-':str) = 'r' `elem` str || 'R' `elem` str
@@ -2668,55 +2672,12 @@ checkCatastrophicRm params t@(T_SimpleCommand id _ tokens) | t `isCommand` "rm"
     skipRepeating c (a:r) = a:skipRepeating c r
     skipRepeating _ [] = []
 
-    addNulls map (Reference (_, token, name)) =
-        if mightBeGuarded token
-        then Map.insert name Nothing map
-        else map
-    addNulls map (Assignment (_, token, name, DataExternal)) =
-        if mightBeGuarded token
-        then Map.insert name Nothing map
-        else Map.insert name (Just "") map
-    addNulls m (Assignment (_, token, name, DataFrom [word]))
-        | mightBeGuarded token = Map.insert name Nothing m
-        | couldFail word       = m
-        | otherwise            = Map.insert name (combine m word) m
-    addNulls m (Assignment (_, token, name, DataFrom _)) =
-        Map.insert name Nothing m
-    addNulls map _ = map
-
-    getScopeId n (Reference (_, token, _)) = getId token
-    getScopeId n (Assignment (_, token, _, _)) = getId token
-    getScopeId n _ = n
-
-    joinMaybes :: [Maybe String] -> Maybe String
-    joinMaybes = foldl (liftM2 (++)) (Just "")
-    combine m = c
-      where
-        c (T_DollarBraced _ t) | unnullable t =
-            Map.findWithDefault (Just "") (concat $ deadSimple t) m
-        c (T_DoubleQuoted _ tokens) = joinMaybes $ map (combine m) tokens
-        c (T_NormalWord _ tokens) = joinMaybes $ map (combine m) tokens
-        c (T_Glob _ "*") = Just "*"
-        c t = getLiteralString t
-
-    couldFail (T_Backticked _ _) = True
-    couldFail (T_DollarExpansion _ _) = True
-    couldFail (T_DoubleQuoted _ foo) = any couldFail foo
-    couldFail (T_NormalWord _ foo) = any couldFail foo
-    couldFail _ = False
-
-    mightBeGuarded token = any t (getPath (parentMap params) token)
-      where
-        t (T_Condition {}) = True
-        t (T_OrIf {}) = True
-        t (T_AndIf {}) = True
-        t _ = False
-
     paths = [
-        "/", "/etc", "/home", "/mnt", "/usr", "/usr/share", "/usr/local",
-        "/var"
+        "", "/bin", "/etc", "/home", "/mnt", "/usr", "/usr/share", "/usr/local",
+        "/var", "/lib"
         ]
-    importantPaths = ["", "/*", "/*/*"] >>= (\x -> map (++x) paths)
+    importantPaths = filter (not . null) $
+        ["", "/", "/*", "/*/*"] >>= (\x -> map (++x) paths)
 checkCatastrophicRm _ _ = return ()