Retain line ending by default.

If no `--end_of_line` was specified, find the first line ending in the input and use that for the whole output.

All tests include checking for differences in line endings.

Closes #552.

.gitattributes

@@ -2,3 +2,15 @@ tests/issue0228.d               text eol=lf
 tests/allman/issue0228.d.ref    text eol=crlf
 tests/knr/issue0228.d.ref       text eol=crlf
 tests/otbs/issue0228.d.ref      text eol=crlf
+tests/issue0552_lf.d            text eol=lf
+tests/allman/issue0552_lf.d.ref text eol=lf
+tests/knr/issue0552_lf.d.ref    text eol=lf
+tests/otbs/issue0552_lf.d.ref   text eol=lf
+tests/issue0552_cr.d            text eol=cr
+tests/allman/issue0552_cr.d.ref text eol=cr
+tests/knr/issue0552_cr.d.ref    text eol=cr
+tests/otbs/issue0552_cr.d.ref   text eol=cr
+tests/issue0552_crlf.d            text eol=crlf
+tests/allman/issue0552_crlf.d.ref text eol=crlf
+tests/knr/issue0552_crlf.d.ref    text eol=crlf
+tests/otbs/issue0552_crlf.d.ref   text eol=crlf

README.md

@@ -91,7 +91,7 @@ void main(string[] args)
 ### Standard EditorConfig properties
 Property Name | Allowed Values | Description
 --------------|----------------|------------
-end_of_line | `cr`, `crlf` and **`lf`** | [See EditorConfig documentation.](https://github.com/editorconfig/editorconfig/wiki/EditorConfig-Properties#end_of_line)
+end_of_line | `cr`, `crlf` and `lf` | [See EditorConfig documentation.](https://github.com/editorconfig/editorconfig/wiki/EditorConfig-Properties#end_of_line) When not set, `dfmt` adopts the first line ending in the input.
 insert_final_newline | **`true`** | Not supported. `dfmt` always inserts a final newline.
 charset | **`UTF-8`** | Not supported. `dfmt` only works correctly on UTF-8.
 indent_style | `tab`, **`space`** | [See EditorConfig documentation.](https://github.com/editorconfig/editorconfig/wiki/EditorConfig-Properties#indent_style)

src/dfmt/config.d

@@ -73,7 +73,7 @@ struct Config
     void initializeWithDefaults()
     {
         pattern = "*.d";
-        end_of_line = EOL.lf;
+        end_of_line = EOL.automatic;
         indent_style = IndentStyle.space;
         indent_size = 4;
         tab_width = 4;

src/dfmt/editorconfig.d

@@ -43,7 +43,8 @@ enum EOL : ubyte
     unspecified,
     lf,
     cr,
-    crlf
+    crlf,
+    automatic
 }
 
 mixin template StandardEditorConfigFields()

src/dfmt/formatter.d

@@ -123,6 +123,23 @@ struct TokenFormatter(OutputRange)
                 this.eolString = "\r\n";
             else if (eol == eol.unspecified)
                 assert(false, "config.end_of_line was unspecified");
+            else
+            {
+                import std.algorithm.searching : countUntil;
+
+                assert (eol == eol.automatic);
+                // Intentional wraparound, -1 turns into uint.max when not found:
+                const firstCR = cast(uint) rawSource.countUntil("\r");
+                if (firstCR < cast(uint) rawSource.countUntil("\n"))
+                {
+                    if (firstCR == rawSource.countUntil("\r\n"))
+                        this.eolString = "\r\n";
+                    else
+                        this.eolString = "\r";
+                }
+                else
+                    this.eolString = "\n";
+            }
         }
     }
 

tests/allman/issue0552_cr.d.ref

@@ -0,0 +1 @@
+/// Testing CR line endings.void main(){}

tests/allman/issue0552_crlf.d.ref

@@ -0,0 +1,4 @@
+/// Testing CRLF line endings.
+void main()
+{
+}

tests/allman/issue0552_lf.d.ref

@@ -0,0 +1,4 @@
+/// Testing LF line endings.
+void main()
+{
+}

tests/issue0552_cr.d

@@ -0,0 +1 @@
+/// Testing CR line endings.void main(){}

tests/issue0552_crlf.d

@@ -0,0 +1,4 @@
+/// Testing CRLF line endings.
+void main()
+{
+}

tests/issue0552_lf.d

@@ -0,0 +1,4 @@
+/// Testing LF line endings.
+void main()
+{
+}

tests/knr/issue0552_cr.d.ref

@@ -0,0 +1 @@
+/// Testing CR line endings.void main(){}

tests/knr/issue0552_crlf.d.ref

@@ -0,0 +1,4 @@
+/// Testing CRLF line endings.
+void main()
+{
+}

tests/knr/issue0552_lf.d.ref

@@ -0,0 +1,4 @@
+/// Testing LF line endings.
+void main()
+{
+}

tests/otbs/issue0552_cr.d.ref

@@ -0,0 +1 @@
+/// Testing CR line endings.void main() {}

tests/otbs/issue0552_crlf.d.ref

@@ -0,0 +1,3 @@
+/// Testing CRLF line endings.
+void main() {
+}

tests/otbs/issue0552_lf.d.ref

@@ -0,0 +1,3 @@
+/// Testing LF line endings.
+void main() {
+}

tests/test.d

@@ -29,13 +29,10 @@ int main()
             if (const result = spawnProcess(dfmtCommand, stdin, File(outFileName, "w")).wait)
                 return result;
 
-            // As long as dfmt defaults to LF line endings (issue #552), we'll have to default to ignore
-            // the line endings in our verification with the reference.
-            const keepTerminator = dfmtCommand.any!(a => a.canFind("--end_of_line")).to!(Flag!"keepTerminator");
             const outText = outFileName.readText;
             const refText = refFileName.readText;
-            const outLines = outText.splitLines(keepTerminator);
-            const refLines = refText.splitLines(keepTerminator);
+            const outLines = outText.splitLines(Yes.keepTerminator);
+            const refLines = refText.splitLines(Yes.keepTerminator);
             foreach (i; 0 .. min(refLines.length, outLines.length))
                 if (outLines[i] != refLines[i])
                 {
@@ -56,26 +53,6 @@ int main()
                 writefln("%(%s%)", [outLines[refLines.length]]);
                 return 1;
             }
-
-            // As long as dfmt defaults to LF line endings (issue #552) we need an explicit trailing newline check.
-            // because a) splitLines gives the same number of lines regardless whether the last line ends with a newline,
-            // and b) when line endings are ignored the trailing endline is of course also ignored.
-            if (outText.endsWithNewline)
-            {
-                if (!refText.endsWithNewline)
-                {
-                    writeln(outFileName, " ends with a newline, but ", refFileName, " does not.");
-                    return 1;
-                }
-            }
-            else
-            {
-                if (refText.endsWithNewline)
-                {
-                    writeln(refFileName, " ends with a newline, but ", outFileName, " does not.");
-                    return 1;
-                }
-            }
         }
 
     foreach (entry; dirEntries("expected_failures", "*.d", SpanMode.shallow))
@@ -88,16 +65,3 @@ int main()
     writeln("All tests succeeded.");
     return 0;
 }
-
-bool endsWithNewline(string text) pure
-{
-    // Same criteria as https://dlang.org/phobos/std_string.html#.lineSplitter
-    return
-        text.endsWith('\n') ||
-        text.endsWith('\r') ||
-        text.endsWith(lineSep) ||
-        text.endsWith(paraSep) ||
-        text.endsWith('\u0085') ||
-        text.endsWith('\v') ||
-        text.endsWith('\f');
-}