[clang] d2627cf - [clang-format] Add the KeepEmptyLinesAtEOF option

[Owen Pan via cfe-commits]

Author: Owen Pan
Date: 2023-06-07T14:17:58-07:00
New Revision: d2627cf88d2553a4c2e850430bdb908a4b7d2e52

URL: https://github.com/llvm/llvm-project/commit/d2627cf88d2553a4c2e850430bdb908a4b7d2e52
DIFF: https://github.com/llvm/llvm-project/commit/d2627cf88d2553a4c2e850430bdb908a4b7d2e52.diff

LOG: [clang-format] Add the KeepEmptyLinesAtEOF option

Adds an option KeepEmptyLinesAtEOF to keep empty lines (up to
MaxEmptyLinesToKeep) before EOF. This remedies the probably unintentional
change in behavior introduced in 3d3ea84a4f8f, which started to always
remove empty lines before EOF.

Fixes #56054.
Fixes #63150.

Differential Revision: https://reviews.llvm.org/D152305

Added: 
    

Modified: 
    clang/docs/ClangFormatStyleOptions.rst
    clang/docs/ReleaseNotes.rst
    clang/include/clang/Format/Format.h
    clang/lib/Format/Format.cpp
    clang/lib/Format/UnwrappedLineFormatter.cpp
    clang/unittests/Format/ConfigParseTest.cpp
    clang/unittests/Format/FormatTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ClangFormatStyleOptions.rst b/clang/docs/ClangFormatStyleOptions.rst
index 8f23a4aa27a92..fa552d65e208a 100644
--- a/clang/docs/ClangFormatStyleOptions.rst
+++ b/clang/docs/ClangFormatStyleOptions.rst
@@ -3555,6 +3555,11 @@ the configuration (without a prefix: ``Auto``).
      false:
      import {VeryLongImportsAreAnnoying, VeryLongImportsAreAnnoying, VeryLongImportsAreAnnoying,} from "some/module.js"
 
+.. _KeepEmptyLinesAtEOF:
+
+**KeepEmptyLinesAtEOF** (``Boolean``) :versionbadge:`clang-format 17` :ref:`¶ <KeepEmptyLinesAtEOF>`
+  Keep empty lines (up to ``MaxEmptyLinesToKeep``) at end of file.
+
 .. _KeepEmptyLinesAtTheStartOfBlocks:
 
 **KeepEmptyLinesAtTheStartOfBlocks** (``Boolean``) :versionbadge:`clang-format 3.7` :ref:`¶ <KeepEmptyLinesAtTheStartOfBlocks>`

diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e24b1cda53711..a30d9f8a38d7e 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -700,6 +700,7 @@ clang-format
 - Fix all known issues associated with ``LambdaBodyIndentation: OuterScope``.
 - Add ``BracedInitializerIndentWidth`` which can be used to configure
   the indentation level of the contents of braced init lists.
+- Add ``KeepEmptyLinesAtEOF`` to keep empty lines at end of file.
 
 libclang
 --------

diff  --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index 6a9d435174cdd..74b3e15918184 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -2675,6 +2675,10 @@ struct FormatStyle {
   bool JavaScriptWrapImports;
   // clang-format on
 
+  /// Keep empty lines (up to ``MaxEmptyLinesToKeep``) at end of file.
+  /// \version 17
+  bool KeepEmptyLinesAtEOF;
+
   /// If true, the empty line at the start of blocks is kept.
   /// \code
   ///    true:                                  false:
@@ -4364,6 +4368,7 @@ struct FormatStyle {
            JavaImportGroups == R.JavaImportGroups &&
            JavaScriptQuotes == R.JavaScriptQuotes &&
            JavaScriptWrapImports == R.JavaScriptWrapImports &&
+           KeepEmptyLinesAtEOF == R.KeepEmptyLinesAtEOF &&
            KeepEmptyLinesAtTheStartOfBlocks ==
                R.KeepEmptyLinesAtTheStartOfBlocks &&
            Language == R.Language &&

diff  --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 6e2b6a662e7e1..5fee5e6c261a9 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -942,6 +942,7 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("JavaScriptWrapImports", Style.JavaScriptWrapImports);
     IO.mapOptional("KeepEmptyLinesAtTheStartOfBlocks",
                    Style.KeepEmptyLinesAtTheStartOfBlocks);
+    IO.mapOptional("KeepEmptyLinesAtEOF", Style.KeepEmptyLinesAtEOF);
     IO.mapOptional("LambdaBodyIndentation", Style.LambdaBodyIndentation);
     IO.mapOptional("LineEnding", Style.LineEnding);
     IO.mapOptional("MacroBlockBegin", Style.MacroBlockBegin);
@@ -1410,6 +1411,7 @@ FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
       /*Hex=*/0,     /*HexMinDigits=*/0};
   LLVMStyle.JavaScriptQuotes = FormatStyle::JSQS_Leave;
   LLVMStyle.JavaScriptWrapImports = true;
+  LLVMStyle.KeepEmptyLinesAtEOF = false;
   LLVMStyle.KeepEmptyLinesAtTheStartOfBlocks = true;
   LLVMStyle.LambdaBodyIndentation = FormatStyle::LBI_Signature;
   LLVMStyle.LineEnding = FormatStyle::LE_DeriveLF;

diff  --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
index fc5d4150ed777..f229742b19d97 100644
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -1513,7 +1513,9 @@ void UnwrappedLineFormatter::formatFirstToken(
     unsigned NewlineIndent) {
   FormatToken &RootToken = *Line.First;
   if (RootToken.is(tok::eof)) {
-    unsigned Newlines = std::min(RootToken.NewlinesBefore, 1u);
+    unsigned Newlines =
+        std::min(RootToken.NewlinesBefore,
+                 Style.KeepEmptyLinesAtEOF ? Style.MaxEmptyLinesToKeep + 1 : 1);
     unsigned TokenIndent = Newlines ? NewlineIndent : 0;
     Whitespaces->replaceWhitespace(RootToken, Newlines, TokenIndent,
                                    TokenIndent);

diff  --git a/clang/unittests/Format/ConfigParseTest.cpp b/clang/unittests/Format/ConfigParseTest.cpp
index 169c93d1143eb..6c720ec22054c 100644
--- a/clang/unittests/Format/ConfigParseTest.cpp
+++ b/clang/unittests/Format/ConfigParseTest.cpp
@@ -167,6 +167,7 @@ TEST(ConfigParseTest, ParsesConfigurationBools) {
   CHECK_PARSE_BOOL(IndentWrappedFunctionNames);
   CHECK_PARSE_BOOL(InsertBraces);
   CHECK_PARSE_BOOL(InsertNewlineAtEOF);
+  CHECK_PARSE_BOOL(KeepEmptyLinesAtEOF);
   CHECK_PARSE_BOOL(KeepEmptyLinesAtTheStartOfBlocks);
   CHECK_PARSE_BOOL(ObjCSpaceAfterProperty);
   CHECK_PARSE_BOOL(ObjCSpaceBeforeProtocolList);

diff  --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index f188ab6f581cf..adc1eda41a91a 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -25744,6 +25744,15 @@ TEST_F(FormatTest, InsertNewlineAtEOF) {
   verifyFormat("int i;\n", "int i;", Style);
 }
 
+TEST_F(FormatTest, KeepEmptyLinesAtEOF) {
+  FormatStyle Style = getLLVMStyle();
+  Style.KeepEmptyLinesAtEOF = true;
+
+  const StringRef Code{"int i;\n\n"};
+  verifyFormat(Code, Code, Style);
+  verifyFormat(Code, "int i;\n\n\n", Style);
+}
+
 TEST_F(FormatTest, SpaceAfterUDL) {
   verifyFormat("auto c = (4s).count();");
   verifyFormat("auto x = 5s .count() == 5;");