Make Lint.Fix.fix return a value that shows whether it was successful

src/Lint.elm

@@ -42,7 +42,7 @@ type LintError
         , message : String
         , details : List String
         , range : Range
-        , fixedSource : Maybe (() -> String)
+        , fixedSource : Maybe (() -> Fix.Result)
         }
 
 
@@ -222,6 +222,6 @@ errorRange (LintError error) =
 
 {-| Get the result of the fix of a rule for an error.
 -}
-fixedSource : LintError -> Maybe (() -> String)
+fixedSource : LintError -> Maybe (() -> Fix.Result)
 fixedSource (LintError error) =
     error.fixedSource

src/Lint/Fix.elm

@@ -1,8 +1,8 @@
 module Lint.Fix exposing
     ( Fix
     , removeRange, replaceRangeBy, insertAt
+    , Result(..), Problem(..), fix
     , mergeRanges
-    , fix
     )
 
 {-| Gives tools to make changes to the source code.
@@ -18,15 +18,15 @@ module Lint.Fix exposing
 @docs removeRange, replaceRangeBy, insertAt
 
 
+# Applying fixes
+
+@docs Result, Problem, fix
+
+
 # Utilitaries for working with ranges
 
 @docs mergeRanges
 
-
-# Applying fixes
-
-@docs fix
-
 -}
 
 import Array
@@ -37,13 +37,21 @@ import Elm.Syntax.Range exposing (Range)
 -- DEFINITION
 
 
-{-| -}
 type Fix
     = Removal Range
     | Replacement Range String
     | InsertAt { row : Int, column : Int } String
 
 
+type Result
+    = Successful String
+    | Errored Problem
+
+
+type Problem
+    = Unchanged
+
+
 
 -- CONSTRUCTORS
 
@@ -73,12 +81,13 @@ insertAt =
 
 {-| Apply the changes on the source code.
 -}
-fix : List Fix -> String -> String
+fix : List Fix -> String -> Result
 fix fixes sourceCode =
     fixes
         |> List.sortBy (rangePosition >> negate)
         |> List.foldl applyFix (String.lines sourceCode)
         |> String.join "\n"
+        |> Successful
 
 
 rangePosition : Fix -> Int

tests/FixTest.elm

@@ -124,9 +124,9 @@ a = Debug.log "foo" 1
                         ]
                 in
                 Fix.fix fixes source
-                    |> Expect.equal """module A exposing (a)
+                    |> Expect.equal (Fix.Successful """module A exposing (a)
 a =  1
-"""
+""")
         , test "should apply a replacement on a single line" <|
             \() ->
                 let
@@ -145,9 +145,9 @@ some_var = 1
                         ]
                 in
                 Fix.fix fixes source
-                    |> Expect.equal """module A exposing (a)
+                    |> Expect.equal (Fix.Successful """module A exposing (a)
 someVar = 1
-"""
+""")
         , test "should insert something on a single line" <|
             \() ->
                 let
@@ -164,9 +164,9 @@ a = 1
                         ]
                 in
                 Fix.fix fixes source
-                    |> Expect.equal """module A exposing (a)
+                    |> Expect.equal (Fix.Successful """module A exposing (a)
 a = Debug.log "foo" 1
-"""
+""")
         , test "should apply multiple fixes regardless of the order" <|
             \() ->
                 let
@@ -190,14 +190,14 @@ a = 1
                 Expect.all
                     [ \() ->
                         Fix.fix fixes source
-                            |> Expect.equal """module A exposing (a)
+                            |> Expect.equal (Fix.Successful """module A exposing (a)
 someVar = Debug.log "foo" 1
-"""
+""")
                     , \() ->
                         Fix.fix (List.reverse fixes) source
-                            |> Expect.equal """module A exposing (a)
+                            |> Expect.equal (Fix.Successful """module A exposing (a)
 someVar = Debug.log "foo" 1
-"""
+""")
                     ]
                     ()
         , test "should apply a removal on multiple lines" <|
@@ -220,11 +220,11 @@ a = 1
                         ]
                 in
                 Fix.fix fixes source
-                    |> Expect.equal """module A exposing (someCode)
+                    |> Expect.equal (Fix.Successful """module A exposing (someCode)
 someCode = 2
 
 
-"""
+""")
         , test "should apply a replacement whose content is on multiple lines" <|
             \() ->
                 let
@@ -243,10 +243,10 @@ some_var = 1
                         ]
                 in
                 Fix.fix fixes source
-                    |> Expect.equal """module A exposing (a)
+                    |> Expect.equal (Fix.Successful """module A exposing (a)
 someVar =
   1
-"""
+""")
         , test "should apply a replacement on multiple lines" <|
             \() ->
                 let
@@ -266,9 +266,9 @@ some_var =
                         ]
                 in
                 Fix.fix fixes source
-                    |> Expect.equal """module A exposing (a)
+                    |> Expect.equal (Fix.Successful """module A exposing (a)
 someVar = 1
-"""
+""")
         , test "should apply a replacement on multiple lines with something on multiple lines" <|
             \() ->
                 let
@@ -288,10 +288,10 @@ some_var =
                         ]
                 in
                 Fix.fix fixes source
-                    |> Expect.equal """module A exposing (a)
+                    |> Expect.equal (Fix.Successful """module A exposing (a)
 foo =
   2
-"""
+""")
         , test "should apply an insertion on multiple lines" <|
             \() ->
                 let
@@ -311,12 +311,12 @@ a = 1
                         ]
                 in
                 Fix.fix fixes source
-                    |> Expect.equal """module A exposing (someCode)
+                    |> Expect.equal (Fix.Successful """module A exposing (someCode)
 someCode = 2
 
 b =
   2
 a : Int
 a = 1
-"""
+""")
         ]