From 50084c06c5706eb7018d213bdf8312e9f0e8725b Mon Sep 17 00:00:00 2001
From: Vidar Holen <spam@vidarholen.net>
Date: Fri, 1 Jul 2016 21:26:46 -0700
Subject: [PATCH] Don't warn when $(seq) is used unquoted.

---
 ShellCheck/ASTLib.hs    | 18 ++++++++++++++++--
 ShellCheck/Analytics.hs |  7 ++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/ShellCheck/ASTLib.hs b/ShellCheck/ASTLib.hs
index ccf183e..c85390d 100644
--- a/ShellCheck/ASTLib.hs
+++ b/ShellCheck/ASTLib.hs
@@ -215,6 +215,19 @@ getCommandName t =
         T_Annotation _ _ t -> getCommandName t
         otherwise -> Nothing
 
+-- If a command substitution is a single command, get its name.
+--  $(date +%s) = Just "date"
+getCommandNameFromExpansion :: Token -> Maybe String
+getCommandNameFromExpansion t =
+    case t of
+        T_DollarExpansion _ [c] -> extract c
+        T_Backticked _ [c] -> extract c
+        T_DollarBraceCommandExpansion _ [c] -> extract c
+        otherwise -> Nothing
+  where
+    extract (T_Pipeline _ _ [cmd]) = getCommandName cmd
+    extract _ = Nothing
+
 -- Get the basename of a token representing a command
 getCommandBasename = liftM basename . getCommandName
   where
@@ -238,8 +251,8 @@ isOnlyRedirection t =
 
 isFunction t = case t of T_Function {} -> True; _ -> False
 
--- Get the list of commands from tokens that contain them, such as
--- the body of while loops and if statements.
+-- Get the lists of commands from tokens that contain them, such as
+-- the body of while loops or branches of if statements.
 getCommandSequences t =
     case t of
         T_Script _ _ cmds -> [cmds]
@@ -252,6 +265,7 @@ getCommandSequences t =
         T_IfExpression _ thens elses -> map snd thens ++ [elses]
         otherwise -> []
 
+-- Get a list of names of associative arrays
 getAssociativeArrays t =
     nub . execWriter $ doAnalysis f t
   where
diff --git a/ShellCheck/Analytics.hs b/ShellCheck/Analytics.hs
index 9dfe2cb..d36b8b4 100644
--- a/ShellCheck/Analytics.hs
+++ b/ShellCheck/Analytics.hs
@@ -765,6 +765,7 @@ prop_checkUnquotedExpansions4 = verifyNot checkUnquotedExpansions "[[ $(foo) ==
 prop_checkUnquotedExpansions5 = verifyNot checkUnquotedExpansions "for f in $(cmd); do echo $f; done"
 prop_checkUnquotedExpansions6 = verifyNot checkUnquotedExpansions "$(cmd)"
 prop_checkUnquotedExpansions7 = verifyNot checkUnquotedExpansions "cat << foo\n$(ls)\nfoo"
+prop_checkUnquotedExpansions8 = verifyNot checkUnquotedExpansions "set -- $(seq 1 4)"
 checkUnquotedExpansions params =
     check
   where
@@ -774,9 +775,12 @@ checkUnquotedExpansions params =
     check _ = return ()
     tree = parentMap params
     examine t =
-        unless (isQuoteFree tree t || usedAsCommandName tree t) $
+        unless (shouldBeSplit t || isQuoteFree tree t || usedAsCommandName tree t) $
             warn (getId t) 2046 "Quote this to prevent word splitting."
 
+    shouldBeSplit t =
+        getCommandNameFromExpansion t == Just "seq"
+
 
 prop_checkRedirectToSame = verify checkRedirectToSame "cat foo > foo"
 prop_checkRedirectToSame2 = verify checkRedirectToSame "cat lol | sed -e 's/a/b/g' > lol"
@@ -1030,6 +1034,7 @@ checkSingleQuotedVariables params t@(T_SingleQuoted id s) =
                 ,"alias"
                 ,"sudo" -- covering "sudo sh" and such
                 ,"dpkg-query"
+                ,"jq"  -- could also check that user provides --arg
                 ]
             || "awk" `isSuffixOf` commandName
             || "perl" `isPrefixOf` commandName