Fix issue #1724

(bash: missing support for 'builtin' keyword)
Now shellcheck looks for the arguments to 'builtin' to determine
read/written variables. A change in the parser makes sure that
assignments are parsed correctly in commands that start with 'builtin'.

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## v0.7.1 - soon
 ### Fixed
 - `-f diff` no longer claims that it found more issues when it didn't
+- SC2154 triggers for builtins called with `builtin`
 
 ### Added
 - SC2254: Suggest quoting expansions in case statements

src/ShellCheck/Analytics.hs

@@ -2168,6 +2168,7 @@ prop_checkUnassignedReferences35= verifyNotTree checkUnassignedReferences "echo
 prop_checkUnassignedReferences36= verifyNotTree checkUnassignedReferences "read -a foo -r <<<\"foo bar\"; echo \"$foo\""
 prop_checkUnassignedReferences37= verifyNotTree checkUnassignedReferences "var=howdy; printf -v 'array[0]' %s \"$var\"; printf %s \"${array[0]}\";"
 prop_checkUnassignedReferences38= verifyTree (checkUnassignedReferences' True) "echo $VAR"
+prop_checkUnassignedReferences39= verifyNotTree checkUnassignedReferences "builtin export var=4; echo $var"
 
 checkUnassignedReferences = checkUnassignedReferences' False
 checkUnassignedReferences' includeGlobals params t = warnings

src/ShellCheck/AnalyzerLib.hs

@@ -567,9 +567,11 @@ getReferencedVariableCommand _ = []
 --   VariableName :: String,   -- The variable name, i.e. foo
 --   VariableValue :: DataType -- A description of the value being assigned, i.e. "Literal string with value foo"
 -- )
-getModifiedVariableCommand base@(T_SimpleCommand _ _ (T_NormalWord _ (T_Literal _ x:_):rest)) =
+getModifiedVariableCommand base@(T_SimpleCommand id cmdPrefix (T_NormalWord _ (T_Literal _ x:_):rest)) =
    filter (\(_,_,s,_) -> not ("-" `isPrefixOf` s)) $
     case x of
+        "builtin" ->
+            getModifiedVariableCommand $ T_SimpleCommand id cmdPrefix rest
         "read" ->
             let params = map getLiteral rest
                 readArrayVars = getReadArrayVariables rest

src/ShellCheck/Parser.hs

@@ -246,6 +246,10 @@ addParseNote n = do
             parseNotes = n : parseNotes state
         }
 
+ignoreProblemsOf p = do
+    systemState <- lift . lift $ Ms.get
+    p <* (lift . lift . Ms.put $ systemState)
+
 shouldIgnoreCode code = do
     context <- getCurrentContexts
     checkSourced <- Mr.asks checkSourced
@@ -2041,7 +2045,11 @@ readSimpleCommand = called "simple command" $ do
 
       Just cmd -> do
             validateCommand cmd
-            suffix <- option [] $ getParser readCmdSuffix cmd [
+            -- We have to ignore possible parsing problems from the lookAhead parser
+            firstArgument <- ignoreProblemsOf . optionMaybe . try . lookAhead $ readCmdWord
+            suffix <- option [] $ getParser readCmdSuffix
+                    -- If `export` or other modifier commands are called with `builtin` we have to look at the first argument
+                    (if isCommand ["builtin"] cmd && isJust firstArgument then fromJust firstArgument else cmd) [
                         (["declare", "export", "local", "readonly", "typeset"], readModifierSuffix),
                         (["time"], readTimeSuffix),
                         (["let"], readLetSuffix),