Make `read -t 0` test more forgiving towards other flags

src/ShellCheck/Analytics.hs

@@ -2809,10 +2809,19 @@ prop_checkReadWithoutR1 = verify checkReadWithoutR "read -a foo"
 prop_checkReadWithoutR2 = verifyNot checkReadWithoutR "read -ar foo"
 prop_checkReadWithoutR3 = verifyNot checkReadWithoutR "read -t 0"
 prop_checkReadWithoutR4 = verifyNot checkReadWithoutR "read -t 0 && read --d '' -r bar"
-prop_checkReadWithoutR5 = verify checkReadWithoutR "read -t 0 foo < file.txt"
+prop_checkReadWithoutR5 = verifyNot checkReadWithoutR "read -t 0 foo < file.txt"
+prop_checkReadWithoutR6 = verifyNot checkReadWithoutR "read -u 3 -t 0"
 checkReadWithoutR _ t@T_SimpleCommand {} | t `isUnqualifiedCommand` "read" =
-    unless (oversimplify t == ["read", "-t", "0"] || "r" `elem` map snd (getAllFlags t)) $
+    unless ("r" `elem` map snd flags || has_t0) $
         info (getId $ getCommandTokenOrThis t) 2162 "read without -r will mangle backslashes."
+  where
+    flags = getAllFlags t
+    has_t0 = fromMaybe False $ do
+        parsed <- getOpts flagsForRead flags
+        t <- getOpt "t" parsed
+        str <- getLiteralString t
+        return $ str == "0"
+
 checkReadWithoutR _ _ = return ()
 
 prop_checkUncheckedCd1 = verifyTree checkUncheckedCdPushdPopd "cd ~/src; rm -r foo"

src/ShellCheck/AnalyzerLib.hs

@@ -932,12 +932,11 @@ isQuotedAlternativeReference t =
 --     Just [("r", -re), ("e", -re), ("d", :), ("u", 3), ("", bar)]
 -- where flags with arguments map to arguments, while others map to themselves.
 -- Any unrecognized flag will result in Nothing.
-getGnuOpts = getOpts getAllFlags
+getGnuOpts str t = getOpts str $ getAllFlags t
-getBsdOpts = getOpts getLeadingFlags
+getBsdOpts str t = getOpts str $ getLeadingFlags t
-getOpts :: (Token -> [(Token, String)]) -> String -> Token -> Maybe [(String, Token)]
+getOpts :: String -> [(Token, String)] -> Maybe [(String, Token)]
-getOpts flagTokenizer string cmd = process flags
+getOpts string flags = process flags
   where
-    flags = flagTokenizer cmd
     flagList (c:':':rest) = ([c], True) : flagList rest
     flagList (c:rest)     = ([c], False) : flagList rest
     flagList []           = []
@@ -959,6 +958,8 @@ getOpts flagTokenizer string cmd = process flags
                 more <- process rest2
                 return $ (flag1, token1) : more
 
+getOpt str flags = snd <$> (listToMaybe $ filter (\(f, _) -> f == str) $ flags)
+
 supportsArrays shell = shell == Bash || shell == Ksh
 
 -- Returns true if the shell is Bash or Ksh (sorry for the name, Ksh)

src/ShellCheck/Checks/Commands.hs

@@ -676,7 +676,7 @@ prop_checkReadExpansions7 = verifyNot checkReadExpansions "read $1"
 prop_checkReadExpansions8 = verifyNot checkReadExpansions "read ${var?}"
 checkReadExpansions = CommandCheck (Exactly "read") check
   where
-    options = getGnuOpts "sreu:n:N:i:p:a:"
+    options = getGnuOpts flagsForRead
     getVars cmd = fromMaybe [] $ do
         opts <- options cmd
         return . map snd $ filter (\(x,_) -> x == "" || x == "a") opts

src/ShellCheck/Data.hs

@@ -136,3 +136,5 @@ shellForExecutable name =
         "ksh88" -> return Ksh
         "ksh93" -> return Ksh
         otherwise -> Nothing
+
+flagsForRead = "sreu:n:N:i:p:a:t:"