Deal with non-existent files more gracefully

So now you can start idris2 with a non-existent file and use :e to start
editing it

src/Core/Directory.idr

@@ -57,15 +57,15 @@ readDataFile fname
 -- looking first in the build directory then in the extra_dirs
 export
 nsToPath : {auto c : Ref Ctxt Defs} ->
-           FC -> List String -> Core String
+           FC -> List String -> Core (Either Error String)
 nsToPath loc ns
     = do d <- getDirs
          let fnameBase = showSep (cast sep) (reverse ns)
          let fs = map (\p => p ++ cast sep ++ fnameBase ++ ".ttc")
                       (build_dir d :: extra_dirs d)
          Just f <- firstAvailable fs
-            | Nothing => throw (ModuleNotFound loc ns)
+            | Nothing => pure (Left (ModuleNotFound loc ns))
-         pure f
+         pure (Right f)
 
 -- Given a namespace, return the full path to the source module (if it
 -- exists in the working directory)

src/Idris/Error.idr

@@ -217,7 +217,7 @@ perror (BadRunElab _ env script)
 perror (GenericMsg _ str) = pure str
 perror (TTCError msg) = pure $ "Error in TTC file: " ++ show msg
 perror (FileErr fname err) 
-    = pure $ "File error in " ++ show fname ++ ": " ++ show err
+    = pure $ "File error in " ++ fname ++ ": " ++ show err
 perror (ParseFail _ err)
     = pure $ show err
 perror (ModuleNotFound _ ns)

src/Idris/ModTree.idr

@@ -145,7 +145,10 @@ buildMod loc num len mod
    = do clearCtxt; addPrimitives
         let src = buildFile mod
         mttc <- getTTCFileName src ".ttc"
-        depFiles <- traverse (nsToPath loc) (imports mod)
+        -- We'd expect any errors in nsToPath to have been caught by now
+        -- since the imports have been built! But we still have to check.
+        depFilesE <- traverse (nsToPath loc) (imports mod)
+        let (ferrs, depFiles) = getEithers depFilesE
         ttcTime <- catch (do t <- fnameModified mttc
                              pure (Just t))
                          (\err => pure Nothing)
@@ -167,10 +170,22 @@ buildMod loc num len mod
                                    ": Building " ++ showMod ++
                                    " (" ++ src ++ ")"
                    [] <- process {u} {m} msg src
-                      | errs => do traverse emitError errs
+                      | errs => do traverse emitError (ferrs ++ errs)
-                                   pure errs
+                                   pure (ferrs ++ errs)
-                   pure []
+                   traverse_ emitError ferrs
-           else pure []
+                   pure ferrs
+           else do traverse_ emitError ferrs
+                   pure ferrs
+  where
+    getEithers : List (Either a b) -> (List a, List b)
+    getEithers [] = ([], [])
+    getEithers (Left x :: es)
+        = let (ls, rs) = getEithers es in
+              (x :: ls, rs)
+    getEithers (Right y :: es)
+        = let (ls, rs) = getEithers es in
+              (ls, y :: rs)
+
 
 buildMods : {auto c : Ref Ctxt Defs} ->
             {auto s : Ref Syn SyntaxInfo} ->

src/Idris/ProcessIdr.idr

@@ -58,7 +58,8 @@ readModule : {auto c : Ref Ctxt Defs} ->
              (as : List String) -> -- Namespace to import into
              Core ()
 readModule top loc vis reexp imp as
-    = do fname <- nsToPath loc imp
+    = do Right fname <- nsToPath loc imp
+               | Left err => throw err
          Just (syn, hash, more) <- logTime ("Reading " ++ show imp) $
                                          readFromTTC {extra = SyntaxInfo} 
                                                   loc vis fname imp as
@@ -89,7 +90,8 @@ readHash : {auto c : Ref Ctxt Defs} ->
            {auto u : Ref UST UState} ->
            Import -> Core (List String, Int)
 readHash imp
-    = do fname <- nsToPath (loc imp) (path imp)
+    = do Right fname <- nsToPath (loc imp) (path imp)
+               | Left err => throw err
          h <- readIFaceHash fname
          -- If the import is a 'public' import, then it forms part of
          -- our own interface so add its hash to our hash

src/Idris/REPL.idr

@@ -373,9 +373,10 @@ loadMainFile : {auto c : Ref Ctxt Defs} ->
                String -> Core ()
 loadMainFile f
     = do resetContext
-         updateErrorLine !(buildDeps f)
          Right res <- coreLift (readFile f)
-            | Left err => setSource ""
+            | Left err => do emitError (FileErr f err)
+                             setSource ""
+         updateErrorLine !(buildDeps f)
          setSource res
 
 -- Returns 'True' if the REPL should continue

tests/Main.idr

@@ -30,7 +30,7 @@ idrisTests
        "basic021", "basic022", "basic023", "basic024",
        "coverage001", "coverage002", "coverage003", "coverage004",
        "error001", "error002", "error003", "error004", "error005",
-       "error006", "error007",
+       "error006", "error007", "error008", "error009",
        "import001", "import002",
        "interactive001", "interactive002", "interactive003", "interactive004",
        "interactive005", "interactive006", "interactive007", "interactive008",

tests/idris2/basic002/run

@@ -1,3 +1,3 @@
-$1 --no-prelude Do.blod < input
+$1 --no-prelude Do.idr < input
 
 rm -rf build

tests/idris2/basic012/run

@@ -1,3 +1,3 @@
-$1 --check VIndex.blod
+$1 --check VIndex.idr
 
 rm -rf build

tests/idris2/error008/expected

@@ -0,0 +1,3 @@
+File error in DoesntExist.idr: File Not Found
+Welcome to Idris 2 version 0.0. Enjoy yourself!
+Main> Bye for now!

tests/idris2/error008/input

@@ -0,0 +1 @@
+:q

tests/idris2/error008/run

@@ -0,0 +1,3 @@
+$1 DoesntExist.idr < input
+
+rm -rf build

tests/idris2/error009/Exists.idr

@@ -0,0 +1,4 @@
+import DoesntExist
+
+foo : Int
+foo = 94

tests/idris2/error009/expected

@@ -0,0 +1,4 @@
+(toplevel):1:1--1:1:DoesntExist not found
+Exists.idr:1:1--3:1:DoesntExist not found
+Welcome to Idris 2 version 0.0. Enjoy yourself!
+Main> Bye for now!

tests/idris2/error009/input

@@ -0,0 +1 @@
+:q

tests/idris2/error009/run

@@ -0,0 +1,3 @@
+$1 Exists.idr < input
+
+rm -rf build

tests/idris2/interface004/run

@@ -1,3 +1,3 @@
-$1 Do.blod < input
+$1 Do.idr < input
 
 rm -rf build

tests/idris2/perror006/run

@@ -1,3 +1,3 @@
-$1 --check PError.run
+$1 --check PError.idr
 
 rm -rf build