[llvm] [YAML] fix output incorrect format for block scalar string (PR #131694)

[Congcong Cai via llvm-commits]

https://github.com/HerrCai0907 updated https://github.com/llvm/llvm-project/pull/131694

>From 8a859768d9cac77985b8affa478d2cdca90931be Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Tue, 18 Mar 2025 10:55:55 +0000
Subject: [PATCH 1/2] [YAML][NFC] precommit wrong test case

---
 llvm/unittests/Support/YAMLIOTest.cpp | 30 +++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/llvm/unittests/Support/YAMLIOTest.cpp b/llvm/unittests/Support/YAMLIOTest.cpp
index c0e9c57a77f19..3db1db57ad596 100644
--- a/llvm/unittests/Support/YAMLIOTest.cpp
+++ b/llvm/unittests/Support/YAMLIOTest.cpp
@@ -1273,6 +1273,36 @@ TEST(YAMLIO, TestReadWriteBlockScalarValue) {
   }
 }
 
+struct V {
+  MultilineStringType doc;
+  std::string str;
+};
+template <> struct MappingTraits<V> {
+  static void mapping(IO &io, V &v) {
+    io.mapRequired("block_scalac", v.doc);
+    io.mapRequired("scalar", v.str);
+  }
+};
+template <> struct llvm::yaml::SequenceElementTraits<V> {
+  static const bool flow = false;
+};
+TEST(YAMLIO, TestScalarAfterBlockScalar) {
+  std::vector<V> v{V{}};
+  v[0].doc.str = "AA\nBB";
+  v[0].str = "a";
+  std::string output;
+  llvm::raw_string_ostream ostr(output);
+  Output yout(ostr);
+  yout << v;
+  EXPECT_EQ(output, R"(---
+- block_scalac:     |
+    AA
+    BB
+scalar:          a
+...
+)");
+}
+
 //===----------------------------------------------------------------------===//
 //  Test flow sequences
 //===----------------------------------------------------------------------===//

>From 521bc6e2d6e93e4a2af07a2d006cdae53b2428ea Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Mon, 17 Mar 2025 23:29:36 +0000
Subject: [PATCH 2/2] [YAML] fix output incorrect format for block scalar
 string

---
 llvm/lib/Support/YAMLTraits.cpp       | 4 ++--
 llvm/unittests/Support/YAMLIOTest.cpp | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Support/YAMLTraits.cpp b/llvm/lib/Support/YAMLTraits.cpp
index 28642e004c4f4..035828b594e84 100644
--- a/llvm/lib/Support/YAMLTraits.cpp
+++ b/llvm/lib/Support/YAMLTraits.cpp
@@ -725,18 +725,18 @@ void Output::blockScalarString(StringRef &S) {
   if (!StateStack.empty())
     newLineCheck();
   output(" |");
-  outputNewLine();
 
   unsigned Indent = StateStack.empty() ? 1 : StateStack.size();
 
   auto Buffer = MemoryBuffer::getMemBuffer(S, "", false);
   for (line_iterator Lines(*Buffer, false); !Lines.is_at_end(); ++Lines) {
+    outputNewLine();
     for (unsigned I = 0; I < Indent; ++I) {
       output("  ");
     }
     output(*Lines);
-    outputNewLine();
   }
+  outputUpToEndOfLine("");
 }
 
 void Output::scalarTag(std::string &Tag) {
diff --git a/llvm/unittests/Support/YAMLIOTest.cpp b/llvm/unittests/Support/YAMLIOTest.cpp
index 3db1db57ad596..5a86555d08fb3 100644
--- a/llvm/unittests/Support/YAMLIOTest.cpp
+++ b/llvm/unittests/Support/YAMLIOTest.cpp
@@ -1298,7 +1298,7 @@ TEST(YAMLIO, TestScalarAfterBlockScalar) {
 - block_scalac:     |
     AA
     BB
-scalar:          a
+  scalar:          a
 ...
 )");
 }