Hide the constructors and raw record fields of message types. (#174)

Finishes #158.

They're not that useful for constructing values (especially after adding the
"unknown fields" case) and were previously mostly used for documentation.  Now
that #172 has landed, we have a better source of documentation that doesn't
expose internal details.

Also change the `Show` instance for messages to be a wrapper around
`showMessageShort`.  This both hides the now-inaccessible record fields and
shortens the output in most cases.  For example:

```
> print (def :: DescriptorProto)
{}
> print (def & #name .~ "hello" & #field .~ [def, def & #name .~ "bye"]:: DescriptorProto)
{name: "hello" field { } field { name: "bye" }}
```

Also bump the resolver for bootstrapping to match the regular build.

proto-lens-protoc/Changelog.md

@@ -3,6 +3,8 @@
 ## v0.4
 - Split out `proto-lens-setup` and `proto-lens-runtime` into separate
   packages.
+- Hide the constructors and record fields of message types, and make `Show`
+  instances call `showMessageShort`.
 - Generate explicit `NFData` instances for each type.
 
 ## v0.3.1.1
@@ -24,14 +26,11 @@
 - Don't generate Haskell modules if they won't be used. (#126)
 - Bundle enum pattern synonyms exports with their type. (#136)
 - Split the `Message` class into separate methods. (#139)
-- Refactor the `FieldDescriptorType. (#147)
+- Refactor the `FieldDescriptorType`. (#147)
 - Add a case to proto3 enums for unknown values. (#137)
 - Track consolidation of `proto-lens-descriptors` into `proto-lens`. (#140)
 - Generate service definitions using promoted datatypes. (#154)
 - Generate prisms for `oneof` message fields. (#160)
-- Build with `haskell-src-exts-1.20.*`. (#170)
-- Add Haddock comments to fields. (#172)
-- Don't unnecessarily touch files. (#177)
 
 ## v0.2.2.3
 - Don't camel-case message names.  This reverts behavior which was added

proto-lens-protoc/src/Data/ProtoLens/Compiler/Combinators.hs

@@ -157,6 +157,9 @@ alt p e = Syntax.Alt () p (Syntax.UnGuardedRhs () e) Nothing
 stringExp :: String -> Exp
 stringExp = Syntax.Lit () . string
 
+charExp :: Char -> Exp
+charExp = Syntax.Lit () . char
+
 tuple :: [Exp] -> Exp
 tuple = Syntax.Tuple () Syntax.Boxed
 
@@ -407,6 +410,9 @@ pLitInt n = Syntax.PLit () sign $ Syntax.Int () n' (show n')
 string :: String -> Syntax.Literal ()
 string s = Syntax.String () s (show s)
 
+char :: Char -> Syntax.Literal ()
+char c = Syntax.Char () c [c]
+
 modifyModuleName :: (String -> String) -> ModuleName -> ModuleName
 modifyModuleName f (Syntax.ModuleName _ unpacked) =
   Syntax.ModuleName () $ f unpacked

proto-lens-protoc/src/Data/ProtoLens/Compiler/Generate.hs

@@ -182,8 +182,10 @@ messageComment fieldModName n fields = unlines
 
 generateMessageExports :: MessageInfo Name -> [ExportSpec]
 generateMessageExports m =
-    map (exportAll . unQual)
-        $ messageName m : map oneofTypeName (messageOneofFields m)
+    -- Hide the message contructor, but expose "oneof" case constructors.
+    exportWith (unQual $ messageName m) []
+        : map (exportAll . unQual . oneofTypeName)
+                (messageOneofFields m)
 
 generateServiceDecls :: Env QName -> ServiceInfo -> [Decl]
 generateServiceDecls env si =
@@ -254,9 +256,16 @@ generateMessageDecls fieldModName syntaxType env protoName info =
                       ]
                       ++ [(messageUnknownFields info, "Data.ProtoLens.FieldSet")]
             ]
-            $ deriving' ["Prelude.Show", "Prelude.Eq", "Prelude.Ord"]
+            $ deriving' ["Prelude.Eq", "Prelude.Ord"]
+    -- instance Show Bar where
+    --   showsPrec __x __s = showChar '{' (showString (showMessageShort __x) (showChar '}' s))
+    , uncommented $
+        instDecl [] ("Prelude.Show" `ihApp` [dataType])
+            [[match "showsPrec" ["_", "__x", "__s"]
+                $ "Prelude.showChar" @@ charExp '{'
+                    @@ ("Prelude.showString" @@ ("Data.ProtoLens.showMessageShort" @@ "__x")
+                        @@ ("Prelude.showChar" @@ charExp '}' @@ "__s"))]]
     ] ++
-
     -- oneof field data type declarations
     -- proto: message Foo {
     --          oneof bar {

proto-lens-tests/tests/enum_test.hs

@@ -10,8 +10,8 @@ module Main where
 import Proto.Enum
     ( Bar(..)
     , Baz(..)
-    , TwoBazs(..)
-    , Foo(..)
+    , TwoBazs
+    , Foo
     , Foo'Baz(..)
     -- explicit import to make sure we get pattern synonyms
     , Alias(..)

proto-lens-tests/tests/oneof_test.hs

@@ -75,13 +75,10 @@ main = testMain
         -- A oneof type and constructor that overlap with an enum
         trivial (Disambiguated'EnumCon' 42 :: Disambiguated'EnumType')
 
-        -- And we don't change the message or enum types and constructors.
-        trivial (Disambiguated'MessageTypeA
-                    {_Disambiguated'MessageTypeA'_unknownFields = []}
-                    :: Disambiguated'MessageTypeA)
-        trivial (Disambiguated'MessageTypeB
-                    {_Disambiguated'MessageTypeB'_unknownFields = []}
-                    :: Disambiguated'MessageTypeB)
+        -- And we don't change the types of messages, nor the types or
+        -- constructors of enums.
+        trivial (def :: Disambiguated'MessageTypeA)
+        trivial (def :: Disambiguated'MessageTypeB)
         trivial (Disambiguated'EnumCon :: Disambiguated'EnumType)
 
     , testCase "not disambiguated names" $ do

proto-lens-tests/tests/proto3_test.hs

@@ -14,7 +14,7 @@ import Data.Monoid ((<>))
 import Proto.Proto3
     ( Foo
     , Foo'FooEnum(..)
-    , Foo'Sub(..)
+    , Foo'Sub
     , Strings
     )
 import Proto.Proto3_Fields

proto-lens/src/Proto/Google/Protobuf/Compiler/Plugin.hs

@@ -6,8 +6,8 @@
 {-# OPTIONS_GHC -fno-warn-unused-imports#-}
 {-# OPTIONS_GHC -fno-warn-duplicate-exports#-}
 module Proto.Google.Protobuf.Compiler.Plugin
-       (CodeGeneratorRequest(..), CodeGeneratorResponse(..),
-        CodeGeneratorResponse'File(..))
+       (CodeGeneratorRequest(), CodeGeneratorResponse(),
+        CodeGeneratorResponse'File())
        where
 import qualified Control.DeepSeq
 import qualified Lens.Labels.Prism
@@ -44,7 +44,12 @@ data CodeGeneratorRequest = CodeGeneratorRequest{_CodeGeneratorRequest'fileToGen
                                                  ![Proto.Google.Protobuf.Descriptor.FileDescriptorProto],
                                                  _CodeGeneratorRequest'_unknownFields ::
                                                  !Data.ProtoLens.FieldSet}
-                          deriving (Prelude.Show, Prelude.Eq, Prelude.Ord)
+                          deriving (Prelude.Eq, Prelude.Ord)
+instance Prelude.Show CodeGeneratorRequest where
+        showsPrec _ __x __s
+          = Prelude.showChar '{'
+              (Prelude.showString (Data.ProtoLens.showMessageShort __x)
+                 (Prelude.showChar '}' __s))
 instance Lens.Labels.HasLens' CodeGeneratorRequest "fileToGenerate"
            ([Data.Text.Text])
          where
@@ -141,7 +146,12 @@ data CodeGeneratorResponse = CodeGeneratorResponse{_CodeGeneratorResponse'error
                                                    ![CodeGeneratorResponse'File],
                                                    _CodeGeneratorResponse'_unknownFields ::
                                                    !Data.ProtoLens.FieldSet}
-                           deriving (Prelude.Show, Prelude.Eq, Prelude.Ord)
+                           deriving (Prelude.Eq, Prelude.Ord)
+instance Prelude.Show CodeGeneratorResponse where
+        showsPrec _ __x __s
+          = Prelude.showChar '{'
+              (Prelude.showString (Data.ProtoLens.showMessageShort __x)
+                 (Prelude.showChar '}' __s))
 instance Lens.Labels.HasLens' CodeGeneratorResponse "error"
            (Data.Text.Text)
          where
@@ -222,7 +232,12 @@ data CodeGeneratorResponse'File = CodeGeneratorResponse'File{_CodeGeneratorRespo
                                                              !(Prelude.Maybe Data.Text.Text),
                                                              _CodeGeneratorResponse'File'_unknownFields
                                                              :: !Data.ProtoLens.FieldSet}
-                                deriving (Prelude.Show, Prelude.Eq, Prelude.Ord)
+                                deriving (Prelude.Eq, Prelude.Ord)
+instance Prelude.Show CodeGeneratorResponse'File where
+        showsPrec _ __x __s
+          = Prelude.showChar '{'
+              (Prelude.showString (Data.ProtoLens.showMessageShort __x)
+                 (Prelude.showChar '}' __s))
 instance Lens.Labels.HasLens' CodeGeneratorResponse'File "name"
            (Data.Text.Text)
          where