Add EOF newline to source code, if not there; Fix #480

src/Fantomas.Tests/CompilerDirectivesTests.fs

@@ -766,3 +766,15 @@ let x = 1
 let x = 1
 #endif
 """
+
+[<Test>]
+let ``inactive code with no newline at EOF #480``() =
+    formatSourceString false """
+#if NOT_DEFINED
+let x = 1
+#endif
+"""  config
+    |> should equal """#if NOT_DEFINED
+let x = 1
+#endif
+"""

src/Fantomas/CodeFormatterImpl.fs

@@ -401,6 +401,13 @@ let isValidFSharpCode formatContext =
             return false
     }
 
+let addNewlineIfNeeded (formattedSourceCode:string) =
+    // When formatting the whole document, an EOL is required
+    if formattedSourceCode.EndsWith(Environment.NewLine) then
+        formattedSourceCode
+    else
+        formattedSourceCode + Environment.NewLine
+
 let formatWith ast formatContext config =
     let moduleName = Path.GetFileNameWithoutExtension formatContext.FileName
     let input =
@@ -410,7 +417,7 @@ let formatWith ast formatContext config =
     // Use '\n' as the new line delimiter consistently
     // It would be easier for F# parser
     let sourceCode = defaultArg input String.Empty
-    let normalizedSourceCode = String.normalizeNewLine sourceCode
+    let normalizedSourceCode = String.normalizeNewLine sourceCode |> addNewlineIfNeeded
     let formattedSourceCode =
         let context = Fantomas.Context.Context.create config formatContext.ProjectOptions.ConditionalCompilationDefines normalizedSourceCode (Some ast)
         context |> genParsedInput { ASTContext.Default with TopLevelModuleName = moduleName } ast
@@ -447,13 +454,6 @@ let format config formatContext =
         return merged
     }
 
-let addNewlineIfNeeded (formattedSourceCode:string) =
-    // When formatting the whole document, an EOL is required
-    if formattedSourceCode.EndsWith(Environment.NewLine) then
-        formattedSourceCode
-    else
-        formattedSourceCode + Environment.NewLine
-
 /// Format a source string using given config
 let formatDocument config formatContext =
     async {