From 41b6e3d5eb81b18998dae6476901cfe60dbf6c7e Mon Sep 17 00:00:00 2001
From: Vidar Holen <spam@vidarholen.net>
Date: Sat, 8 Apr 2017 14:37:58 -0700
Subject: [PATCH] Don't warn about [ -v foo ] being unassigned.

---
 ShellCheck/Analytics.hs   | 18 +++++++++++++++---
 ShellCheck/AnalyzerLib.hs | 25 ++++++++++++++++++++++---
 2 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/ShellCheck/Analytics.hs b/ShellCheck/Analytics.hs
index b28fecc..7bb86d4 100644
--- a/ShellCheck/Analytics.hs
+++ b/ShellCheck/Analytics.hs
@@ -1795,6 +1795,7 @@ prop_checkUnused32= verifyTree checkUnusedAssignments "let a=b=c; echo $a"
 prop_checkUnused33= verifyNotTree checkUnusedAssignments "a=foo; [[ foo =~ ^{$a}$ ]]"
 prop_checkUnused34= verifyNotTree checkUnusedAssignments "foo=1; (( t = foo )); echo $t"
 prop_checkUnused35= verifyNotTree checkUnusedAssignments "a=foo; b=2; echo ${a:b}"
+prop_checkUnused36= verifyNotTree checkUnusedAssignments "if [[ -v foo ]]; then true; fi"
 checkUnusedAssignments params t = execWriter (mapM_ warnFor unused)
   where
     flow = variableFlow params
@@ -1845,6 +1846,10 @@ prop_checkUnassignedReferences25= verifyNotTree checkUnassignedReferences "decla
 prop_checkUnassignedReferences26= verifyNotTree checkUnassignedReferences "a::b() { foo; }; readonly -f a::b"
 prop_checkUnassignedReferences27= verifyNotTree checkUnassignedReferences ": ${foo:=bar}"
 prop_checkUnassignedReferences28= verifyNotTree checkUnassignedReferences "#!/bin/ksh\necho \"${.sh.version}\"\n"
+prop_checkUnassignedReferences29= verifyNotTree checkUnassignedReferences "if [[ -v foo ]]; then echo $foo; fi"
+prop_checkUnassignedReferences30= verifyNotTree checkUnassignedReferences "if [[ -v foo[3] ]]; then echo ${foo[3]}; fi"
+prop_checkUnassignedReferences31= verifyNotTree checkUnassignedReferences "X=1; if [[ -v foo[$X+42] ]]; then echo ${foo[$X+42]}; fi"
+prop_checkUnassignedReferences32= verifyNotTree checkUnassignedReferences "if [[ -v \"foo[1]\" ]]; then echo ${foo[@]}; fi"
 checkUnassignedReferences params t = warnings
   where
     (readMap, writeMap) = execState (mapM tally $ variableFlow params) (Map.empty, Map.empty)
@@ -2415,12 +2420,19 @@ prop_checkTestArgumentSplitting12 = verify checkTestArgumentSplitting "[ *.png ]
 prop_checkTestArgumentSplitting13 = verify checkTestArgumentSplitting "[ \"$@\" == \"\" ]"
 prop_checkTestArgumentSplitting14 = verify checkTestArgumentSplitting "[[ \"$@\" == \"\" ]]"
 prop_checkTestArgumentSplitting15 = verifyNot checkTestArgumentSplitting "[[ \"$*\" == \"\" ]]"
+prop_checkTestArgumentSplitting16 = verifyNot checkTestArgumentSplitting "[[ -v foo[123] ]]"
 checkTestArgumentSplitting :: Parameters -> Token -> Writer [TokenComment] ()
 checkTestArgumentSplitting _ t =
     case t of
-        (TC_Unary _ _ op token) | isGlob token ->
-            err (getId token) 2144 $
-               op ++ " doesn't work with globs. Use a for loop."
+        (TC_Unary _ typ op token) | isGlob token ->
+            if op == "-v"
+            then
+                when (typ == SingleBracket) $
+                    err (getId token) 2208 $
+                      "Use [[ ]] or quote arguments to -v to avoid glob expansion."
+            else
+                err (getId token) 2144 $
+                   op ++ " doesn't work with globs. Use a for loop."
 
         (TC_Nullary _ typ token) -> do
             checkBraces typ token
diff --git a/ShellCheck/AnalyzerLib.hs b/ShellCheck/AnalyzerLib.hs
index d73d3da..dc7a02c 100644
--- a/ShellCheck/AnalyzerLib.hs
+++ b/ShellCheck/AnalyzerLib.hs
@@ -94,7 +94,12 @@ data StackData =
 data DataType = DataString DataSource | DataArray DataSource
   deriving (Show)
 
-data DataSource = SourceFrom [Token] | SourceExternal | SourceDeclaration | SourceInteger
+data DataSource =
+    SourceFrom [Token]
+    | SourceExternal
+    | SourceDeclaration
+    | SourceInteger
+    | SourceChecked
   deriving (Show)
 
 data VariableState = Dead Token String | Alive deriving (Show)
@@ -388,6 +393,18 @@ getModifiedVariables t =
             name <- getLiteralString lhs
             return (t, t, name, DataString $ SourceFrom [rhs])
 
+        -- Count [[ -v foo ]] as an "assignment".
+        -- This is to prevent [ -v foo ] being unassigned or unused.
+        TC_Unary id _ "-v" token -> maybeToList $ do
+            str <- fmap (takeWhile (/= '[')) $ -- Quoted index
+                    flip getLiteralStringExt token $ \x ->
+                case x of
+                    T_Glob _ s -> return s -- Unquoted index
+                    _ -> Nothing
+
+            guard . not . null $ str
+            return (t, token, str, DataString $ SourceChecked)
+
         T_DollarBraced _ l -> maybeToList $ do
             let string = bracedString t
             let modifier = getBracedModifier string
@@ -584,8 +601,10 @@ getReferencedVariables parents t =
                 getVariablesFromLiteralToken word
         else []
 
-    literalizer TA_Index {} = return ""  -- x[0] becomes a reference of x
-    literalizer _ = Nothing
+    literalizer t = case t of
+        TA_Index {} -> return ""  -- x[0] becomes a reference of x
+        T_Glob _ s -> return s    -- Also when parsed as globs
+        _ -> Nothing
 
     getIfReference context token = maybeToList $ do
             str <- getLiteralStringExt literalizer token