Initial support for portage

Portage (Gentoo's package manager) packages are made up of ebuild and
eclass files.  These are essentially bash scripts with a bunch of
predefined functions, global variables, and some external semantics
(e.g. "inherit" is a wrapper around "source" that incorporates an
expected filesystem layout).

Add automatic detection of portage by mapping .ebuild and .eclass files
to bash with an extra Parameters flag that indicates they're a portage
build file.  This leaves all the bash checks as they are, but allows
additional tweaks to be made for "portage mode".  No actual checks are
added here; subsequent changes will add portage-specific behavior.

CHANGELOG.md

@@ -16,6 +16,7 @@
 - json1 format like --format=json but treats tabs as single characters
 - Recognize FLAGS variables created by the shflags library.
 - Site-specific changes can now be made in Custom.hs for ease of patching
+- Add portage as a bash-like shell for ebuild/eclass files.
 - SC2154: Also warn about unassigned uppercase variables (optional)
 - SC2252: Warn about `[ $a != x ] || [ $a != y ]`, similar to SC2055
 - SC2251: Inform about ineffectual ! in front of commands

shellcheck.1.md

@@ -87,8 +87,9 @@ not warn at all, as `ksh` supports decimals in arithmetic contexts.
 
 :   Specify Bourne shell dialect. Valid values are *sh*, *bash*, *dash* and *ksh*.
     The default is to deduce the shell from the file's `shell` directive,
-    shebang, or `.bash/.bats/.dash/.ksh` extension, in that order. *sh* refers to
-    POSIX `sh` (not the system's), and will warn of portability issues.
+    shebang, or `.bash/.bats/.dash/.ksh/.ebuild/.eclass` extension, in that
+    order. *sh* refers to POSIX `sh` (not the system's), and will warn of
+    portability issues.
 
 **-S**\ *SEVERITY*,\ **--severity=***severity*
 

src/ShellCheck/AnalyzerLib.hs

@@ -92,7 +92,9 @@ data Parameters = Parameters {
     -- The root node of the AST
     rootNode           :: Token,
     -- map from token id to start and end position
-    tokenPositions     :: Map.Map Id (Position, Position)
+    tokenPositions     :: Map.Map Id (Position, Position),
+    -- True if script is being used as a portage build file
+    isPortageBuild     :: Bool
     } deriving (Show)
 
 -- TODO: Cache results of common AST ops here
@@ -195,7 +197,8 @@ makeParameters spec =
         shellTypeSpecified = isJust (asShellType spec) || isJust (asFallbackShell spec),
         parentMap = getParentTree root,
         variableFlow = getVariableFlow params root,
-        tokenPositions = asTokenPositions spec
+        tokenPositions = asTokenPositions spec,
+        isPortageBuild = asIsPortageBuild spec
     } in params
   where root = asScript spec
 

src/ShellCheck/Checker.hs

@@ -53,12 +53,18 @@ shellFromFilename filename = foldl mplus Nothing candidates
     shellExtensions = [(".ksh", Ksh)
                       ,(".bash", Bash)
                       ,(".bats", Bash)
-                      ,(".dash", Dash)]
+                      ,(".dash", Dash)
+                      ,(".ebuild", Bash)
+                      ,(".eclass", Bash)]
                       -- The `.sh` is too generic to determine the shell:
                       -- We fallback to Bash in this case and emit SC2148 if there is no shebang
     candidates =
         map (\(ext,sh) -> if ext `isSuffixOf` filename then Just sh else Nothing) shellExtensions
 
+isPortageBuildFile filename = any (\x -> isSuffixOf x filename) portageExtensions
+  where
+    portageExtensions = [".ebuild", ".eclass"]
+
 checkScript :: Monad m => SystemInterface m -> CheckSpec -> m CheckResult
 checkScript sys spec = do
     results <- checkScript (csScript spec)
@@ -85,7 +91,8 @@ checkScript sys spec = do
                     asCheckSourced = csCheckSourced spec,
                     asExecutionMode = Executed,
                     asTokenPositions = tokenPositions,
-                    asOptionalChecks = csOptionalChecks spec
+                    asOptionalChecks = csOptionalChecks spec,
+                    asIsPortageBuild = isPortageBuildFile $ csFilename spec
                 } where as = newAnalysisSpec root
         let analysisMessages =
                 fromMaybe [] $

src/ShellCheck/Interface.hs

@@ -25,7 +25,7 @@ module ShellCheck.Interface
     , CheckResult(crFilename, crComments)
     , ParseSpec(psFilename, psScript, psCheckSourced, psIgnoreRC, psShellTypeOverride)
     , ParseResult(prComments, prTokenPositions, prRoot)
-    , AnalysisSpec(asScript, asShellType, asFallbackShell, asExecutionMode, asCheckSourced, asTokenPositions, asOptionalChecks)
+    , AnalysisSpec(asScript, asShellType, asFallbackShell, asExecutionMode, asCheckSourced, asTokenPositions, asOptionalChecks, asIsPortageBuild)
     , AnalysisResult(arComments)
     , FormatterOptions(foColorOption, foWikiLinkCount)
     , Shell(Ksh, Sh, Bash, Dash)
@@ -161,7 +161,8 @@ data AnalysisSpec = AnalysisSpec {
     asExecutionMode :: ExecutionMode,
     asCheckSourced :: Bool,
     asOptionalChecks :: [String],
-    asTokenPositions :: Map.Map Id (Position, Position)
+    asTokenPositions :: Map.Map Id (Position, Position),
+    asIsPortageBuild :: Bool
 }
 
 newAnalysisSpec token = AnalysisSpec {
@@ -171,7 +172,8 @@ newAnalysisSpec token = AnalysisSpec {
     asExecutionMode = Executed,
     asCheckSourced = False,
     asOptionalChecks = [],
-    asTokenPositions = Map.empty
+    asTokenPositions = Map.empty,
+    asIsPortageBuild = False
 }
 
 newtype AnalysisResult = AnalysisResult {