fix: use old type name in Union migration type signatures for renamed types

extra/Lamdera/Evergreen/MigrationGenerator.hs

@@ -172,7 +172,7 @@ coreTypeMigration typeDidChange oldVersion newVersion interfaces newModule typeN
 
         (Just typeDefOld@(Union mOld typeNameOld unionOld), Just (Union mNew typeNameNew unionNew)) -> do
           let
-            unionDefMigration = migrateUnionDefinition typeDefOld oldVersion newVersion newModule identifier typeName interfaces recursionSet [] [] unionNew
+            unionDefMigration = migrateUnionDefinition typeDefOld oldVersion newVersion newModule identifier typeNameOld interfaces recursionSet [] [] unionNew
 
             (MigrationNested migrationImpl imps subDefs) = unionDefMigration
             migration = T.concat ["\n    ", migrationWrapperForType typeName, " ( ", migrationImpl, " old, Cmd.none )"]
@@ -193,16 +193,18 @@ coreTypeMigration typeDidChange oldVersion newVersion interfaces newModule typeN
 
 -- A top level Custom Type definition i.e. `type Herp = Derp ...`
 migrateUnionDefinition :: TypeDef -> Int -> Int -> ModuleName.Canonical -> TypeIdentifier -> N.Name -> Interfaces -> RecursionSet -> TvarMap -> TvarMap -> Can.Union -> Migration
-migrateUnionDefinition typeDefOld oldVersion newVersion scope identifier@(author, pkg, newModule, tipe) typeNameNew interfaces recursionSet tvarMapOld tvarMapNew newUnion =
+migrateUnionDefinition typeDefOld oldVersion newVersion scope identifier@(author, pkg, newModule, tipe) typeNameOld interfaces recursionSet tvarMapOld tvarMapNew newUnion =
+  let typeNameNew = tipe
+  in
   case typeDefOld of
-    (Alias moduleNameOld typeNameOld aliasOld) ->
+    (Alias moduleNameOld typeNameOld_ aliasOld) ->
       unimplemented "" ("`" <> N.toText typeNameNew <> "` was a type alias, but now it's a custom type. I need you to write this migration.")
-    (Union moduleNameOld typeNameOld unionOld) ->
-      migrateUnionDefinition_ author pkg unionOld newUnion tvarMapOld tvarMapNew oldVersion newVersion typeNameNew newModule identifier (dropCan moduleNameOld) interfaces recursionSet scope
+    (Union moduleNameOld typeNameOld_ unionOld) ->
+      migrateUnionDefinition_ author pkg unionOld newUnion tvarMapOld tvarMapNew oldVersion newVersion typeNameOld typeNameNew newModule identifier (dropCan moduleNameOld) interfaces recursionSet scope
 
 
-migrateUnionDefinition_ :: Pkg.Author -> Pkg.Project -> Can.Union -> Can.Union -> TvarMap -> TvarMap -> Int -> Int -> N.Name -> N.Name -> TypeIdentifier -> N.Name -> Interfaces -> RecursionSet -> ModuleName.Canonical -> Migration
-migrateUnionDefinition_ author pkg oldUnion newUnion tvarMapOld tvarMapNew oldVersion newVersion typeName newModule identifier oldModuleName interfaces recursionSet scope =
+migrateUnionDefinition_ :: Pkg.Author -> Pkg.Project -> Can.Union -> Can.Union -> TvarMap -> TvarMap -> Int -> Int -> N.Name -> N.Name -> N.Name -> TypeIdentifier -> N.Name -> Interfaces -> RecursionSet -> ModuleName.Canonical -> Migration
+migrateUnionDefinition_ author pkg oldUnion newUnion tvarMapOld tvarMapNew oldVersion newVersion typeNameOld typeName newModule identifier oldModuleName interfaces recursionSet scope =
   let
     oldModuleNameCanonical :: ModuleName.Canonical
     oldModuleNameCanonical = ModuleName.Canonical (Pkg.Name author pkg) oldModuleName
@@ -276,7 +278,7 @@ migrateUnionDefinition_ author pkg oldUnion newUnion tvarMapOld tvarMapNew oldVe
     migrationTypeSignature = T.concat
       [ paramMigrationFnsTypeSig & T.intercalate " -> " & suffixIfNonempty " -> "
       , " "
-      , oldModuleName & N.toText, ".", typeName & N.toText
+      , oldModuleName & N.toText, ".", typeNameOld & N.toText
       , " "
       , tvarsOld & fmap (\tvar -> T.concat [N.toText tvar, "_old"]) & T.intercalate " "
       , " -> "
@@ -920,6 +922,12 @@ typeToMigration oldVersion newVersion scope interfaces recursionSet_ typeNew@(Ca
               canToMigration oldVersion newVersion scope interfaces newRecursionSet p0 (Just (p0o)) tvarMapOld tvarMapNew anonymousValueRef
           in
           T.concat [ "(\\", anonymousValueRef, " -> ", migration, ")"]
+        else if not (T.isPrefixOf "(" migrate_p0) && "|>" `T.isInfixOf` migrate_p0 then
+          -- Raw pipeline migrations (e.g. nested Dict/SeqDict) must be wrapped
+          -- in a lambda so they can be passed as function arguments to
+          -- Tuple.mapBoth, List.map, etc. Already-parenthesised expressions
+          -- (e.g. lambdas like `(\(t1,t2,t3) -> ...)`) are skipped.
+          T.concat [ "(\\v__ -> v__ |> ", migrate_p0, ")" ]
         else
           T.concat [ migrate_p0 ]
 
@@ -1051,7 +1059,7 @@ migrateTypeDef typeOld typeNew oldVersion newVersion interfaces tvarMapOld tvarM
       in
       -- @TODO use unionOld instead of typeDefOld
       -- @TODO pass params
-      migrateUnionDefinition typeDefOld oldVersion newVersion mNew identifier typeNameNew interfaces newRecursionSet tvarMapOld tvarMapNew unionNew
+      migrateUnionDefinition typeDefOld oldVersion newVersion mNew identifier typeNameOld interfaces newRecursionSet tvarMapOld tvarMapNew unionNew
         & debugMigrationIncludes_ "migrateTypeDef:Union" (typeOld, typeNew)
 
     -- @ADVANCED handle case where user is aliasing a custom type?

test/Test/Lamdera/Evergreen/TestMigrationGenerator.hs

@@ -114,6 +114,8 @@ testExamples = withTestEnv $ do
         -- , "src/Test/Migrate_External_Wrap.elm"
           "src/Migrate_External_Paramed"
         , "src/Migrate_All"
+        , "src/Migrate_Union_Renamed"
+        , "src/Migrate_Nested_Dict"
         ]
 
     catchTestException :: FilePath -> SomeException -> IO a

test/scenario-migration-generate/src/Migrate_Nested_Dict/Actual.elm

@@ -0,0 +1,35 @@
+module Migrate_Nested_Dict.Actual exposing (..)
+
+{-| This migration file was automatically generated by the lamdera compiler.
+
+It includes:
+
+  - A migration for each of the 6 Lamdera core types that has changed
+  - A function named `migrate_ModuleName_TypeName` for each changed/custom type
+
+Expect to see:
+
+  - `Unimplementеd` values as placeholders wherever I was unable to figure out a clear migration path for you
+  - `@NOTICE` comments for things you should know about, i.e. new custom type constructors that won't get any
+    value mappings from the old type by default
+
+You can edit this file however you wish! It won't be generated again.
+
+See <https://dashboard.lamdera.app/docs/evergreen> for more info.
+
+-}
+
+import Lamdera.Migrations exposing (..)
+import Migrate_Nested_Dict.New
+import Migrate_Nested_Dict.Old
+
+
+target =
+    migrate_Migrate_Nested_Dict_New_Target
+
+
+migrate_Migrate_Nested_Dict_New_Target : Migrate_Nested_Dict.Old.Target -> Migrate_Nested_Dict.New.Target
+migrate_Migrate_Nested_Dict_New_Target old =
+    case old of
+        Migrate_Nested_Dict.Old.Wrapper p0 ->
+            Migrate_Nested_Dict.New.Wrapper (p0 |> Dict.toList |> List.map (Tuple.mapBoth (Unimplemented {- Type changed from `Int` to `String`. I need you to write this migration. -}) (Dict.toList |> List.map (Tuple.mapFirst (Unimplemented {- Type changed from `Int` to `String`. I need you to write this migration. -})) |> Dict.fromList)) |> Dict.fromList)

test/scenario-migration-generate/src/Migrate_Nested_Dict/Expected.elm

@@ -0,0 +1,35 @@
+module Migrate_Nested_Dict.Expected exposing (..)
+
+{-| This migration file was automatically generated by the lamdera compiler.
+
+It includes:
+
+  - A migration for each of the 6 Lamdera core types that has changed
+  - A function named `migrate_ModuleName_TypeName` for each changed/custom type
+
+Expect to see:
+
+  - `Unimplementеd` values as placeholders wherever I was unable to figure out a clear migration path for you
+  - `@NOTICE` comments for things you should know about, i.e. new custom type constructors that won't get any
+    value mappings from the old type by default
+
+You can edit this file however you wish! It won't be generated again.
+
+See <https://dashboard.lamdera.app/docs/evergreen> for more info.
+
+-}
+
+import Lamdera.Migrations exposing (..)
+import Migrate_Nested_Dict.New
+import Migrate_Nested_Dict.Old
+
+
+target =
+    migrate_Migrate_Nested_Dict_New_Target
+
+
+migrate_Migrate_Nested_Dict_New_Target : Migrate_Nested_Dict.Old.Target -> Migrate_Nested_Dict.New.Target
+migrate_Migrate_Nested_Dict_New_Target old =
+    case old of
+        Migrate_Nested_Dict.Old.Wrapper p0 ->
+            Migrate_Nested_Dict.New.Wrapper (p0 |> Dict.toList |> List.map (Tuple.mapBoth (Unimplemented {- Type changed from `Int` to `String`. I need you to write this migration. -}) (\v__ -> v__ |> Dict.toList |> List.map (Tuple.mapFirst (Unimplemented {- Type changed from `Int` to `String`. I need you to write this migration. -})) |> Dict.fromList)) |> Dict.fromList)

test/scenario-migration-generate/src/Migrate_Nested_Dict/New.elm

@@ -0,0 +1,7 @@
+module Migrate_Nested_Dict.New exposing (..)
+
+import Dict exposing (Dict)
+
+
+type Target
+    = Wrapper (Dict String (Dict String Int))

test/scenario-migration-generate/src/Migrate_Nested_Dict/Old.elm

@@ -0,0 +1,7 @@
+module Migrate_Nested_Dict.Old exposing (..)
+
+import Dict exposing (Dict)
+
+
+type Target
+    = Wrapper (Dict Int (Dict Int Int))

test/scenario-migration-generate/src/Migrate_Union_Renamed/Actual.elm

@@ -0,0 +1,45 @@
+module Migrate_Union_Renamed.Actual exposing (..)
+
+{-| This migration file was automatically generated by the lamdera compiler.
+
+It includes:
+
+  - A migration for each of the 6 Lamdera core types that has changed
+  - A function named `migrate_ModuleName_TypeName` for each changed/custom type
+
+Expect to see:
+
+  - `Unimplementеd` values as placeholders wherever I was unable to figure out a clear migration path for you
+  - `@NOTICE` comments for things you should know about, i.e. new custom type constructors that won't get any
+    value mappings from the old type by default
+
+You can edit this file however you wish! It won't be generated again.
+
+See <https://dashboard.lamdera.app/docs/evergreen> for more info.
+
+-}
+
+import Lamdera.Migrations exposing (..)
+import Migrate_Union_Renamed.New
+import Migrate_Union_Renamed.Old
+
+
+target =
+    migrate_Migrate_Union_Renamed_New_Target
+
+
+migrate_Migrate_Union_Renamed_New_CompanyType : Migrate_Union_Renamed.Old.CompanyType -> Migrate_Union_Renamed.New.CompanyType
+migrate_Migrate_Union_Renamed_New_CompanyType old =
+    case old of
+        Migrate_Union_Renamed.Old.Individual ->
+            Migrate_Union_Renamed.New.Individual
+
+        Migrate_Union_Renamed.Old.Corporation ->
+            Migrate_Union_Renamed.New.Corporation
+
+
+migrate_Migrate_Union_Renamed_New_Target : Migrate_Union_Renamed.Old.Target -> Migrate_Union_Renamed.New.Target
+migrate_Migrate_Union_Renamed_New_Target old =
+    case old of
+        Migrate_Union_Renamed.Old.Wrapper p0 ->
+            Migrate_Union_Renamed.New.Wrapper (p0 |> migrate_Migrate_Union_Renamed_New_CompanyType)

test/scenario-migration-generate/src/Migrate_Union_Renamed/Expected.elm

@@ -0,0 +1,45 @@
+module Migrate_Union_Renamed.Expected exposing (..)
+
+{-| This migration file was automatically generated by the lamdera compiler.
+
+It includes:
+
+  - A migration for each of the 6 Lamdera core types that has changed
+  - A function named `migrate_ModuleName_TypeName` for each changed/custom type
+
+Expect to see:
+
+  - `Unimplementеd` values as placeholders wherever I was unable to figure out a clear migration path for you
+  - `@NOTICE` comments for things you should know about, i.e. new custom type constructors that won't get any
+    value mappings from the old type by default
+
+You can edit this file however you wish! It won't be generated again.
+
+See <https://dashboard.lamdera.app/docs/evergreen> for more info.
+
+-}
+
+import Lamdera.Migrations exposing (..)
+import Migrate_Union_Renamed.New
+import Migrate_Union_Renamed.Old
+
+
+target =
+    migrate_Migrate_Union_Renamed_New_Target
+
+
+migrate_Migrate_Union_Renamed_New_CompanyType : Migrate_Union_Renamed.Old.MoralType -> Migrate_Union_Renamed.New.CompanyType
+migrate_Migrate_Union_Renamed_New_CompanyType old =
+    case old of
+        Migrate_Union_Renamed.Old.Individual ->
+            Migrate_Union_Renamed.New.Individual
+
+        Migrate_Union_Renamed.Old.Corporation ->
+            Migrate_Union_Renamed.New.Corporation
+
+
+migrate_Migrate_Union_Renamed_New_Target : Migrate_Union_Renamed.Old.Target -> Migrate_Union_Renamed.New.Target
+migrate_Migrate_Union_Renamed_New_Target old =
+    case old of
+        Migrate_Union_Renamed.Old.Wrapper p0 ->
+            Migrate_Union_Renamed.New.Wrapper (p0 |> migrate_Migrate_Union_Renamed_New_CompanyType)

test/scenario-migration-generate/src/Migrate_Union_Renamed/New.elm

@@ -0,0 +1,10 @@
+module Migrate_Union_Renamed.New exposing (..)
+
+
+type Target
+    = Wrapper CompanyType
+
+
+type CompanyType
+    = Individual
+    | Corporation

test/scenario-migration-generate/src/Migrate_Union_Renamed/Old.elm

@@ -0,0 +1,10 @@
+module Migrate_Union_Renamed.Old exposing (..)
+
+
+type Target
+    = Wrapper MoralType
+
+
+type MoralType
+    = Individual
+    | Corporation