From da283b54d964c4b08395baa57d8b33dcb59dfd07 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano@gmail.com>
Date: Mon, 14 Jul 2025 21:15:07 -0700
Subject: [PATCH] Revert "[clang-format] Fix an off-by-1 bug with -length
 option (#143302)"

This reverts commit 1fae5918b3d6fbed8ce6d8a2edf31bdf304ca8db because it may
break VSCode.

Closes #146036
---
 clang/test/Format/multiple-inputs-error.cpp |  2 +-
 clang/test/Format/ranges.cpp                | 11 +----------
 clang/tools/clang-format/ClangFormat.cpp    | 10 +++-------
 3 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/clang/test/Format/multiple-inputs-error.cpp b/clang/test/Format/multiple-inputs-error.cpp
index 7cb835d39f23..1aa9c9f3e2fa 100644
--- a/clang/test/Format/multiple-inputs-error.cpp
+++ b/clang/test/Format/multiple-inputs-error.cpp
@@ -1,6 +1,6 @@
 // RUN: cp %s %t-1.cpp
 // RUN: cp %s %t-2.cpp
-// RUN: not clang-format 2>&1 >/dev/null -offset=1 -length=1 %t-1.cpp %t-2.cpp |FileCheck %s
+// RUN: not clang-format 2>&1 >/dev/null -offset=1 -length=0 %t-1.cpp %t-2.cpp |FileCheck %s
 // RUN: not clang-format 2>&1 >/dev/null -lines=1:1 %t-1.cpp %t-2.cpp |FileCheck %s -check-prefix=CHECK-LINE
 // CHECK: error: -offset, -length and -lines can only be used for single file.
 // CHECK-LINE: error: -offset, -length and -lines can only be used for single file.
diff --git a/clang/test/Format/ranges.cpp b/clang/test/Format/ranges.cpp
index f42492e43f84..66b984e037b3 100644
--- a/clang/test/Format/ranges.cpp
+++ b/clang/test/Format/ranges.cpp
@@ -1,5 +1,5 @@
 // RUN: grep -Ev "// *[A-Z-]+:" %s \
-// RUN:   | clang-format -style=LLVM -offset=2 -length=1 -offset=28 -length=1 -offset=35 -length=8 \
+// RUN:   | clang-format -style=LLVM -offset=2 -length=0 -offset=28 -length=0 \
 // RUN:   | FileCheck -strict-whitespace %s
 // CHECK: {{^int\ \*i;$}}
 int*i;
@@ -9,12 +9,3 @@ int  *  i;
 
 // CHECK: {{^int\ \*i;$}}
 int   *   i;
-
-// CHECK: int I;
-// CHECK-NEXT: int J ;
-int I ;
-int J ;
-
-// RUN: not clang-format -length=0 %s 2>&1 \
-// RUN:   | FileCheck -strict-whitespace -check-prefix=CHECK0 %s
-// CHECK0: error: length should be at least 1
diff --git a/clang/tools/clang-format/ClangFormat.cpp b/clang/tools/clang-format/ClangFormat.cpp
index c0efbb7588cc..24ad3cb42254 100644
--- a/clang/tools/clang-format/ClangFormat.cpp
+++ b/clang/tools/clang-format/ClangFormat.cpp
@@ -284,7 +284,7 @@ static bool fillRanges(MemoryBuffer *Code,
   if (Offsets.size() == 1 && EmptyLengths) {
     Length = Sources.getFileOffset(Sources.getLocForEndOfFile(ID)) - Offsets[0];
   } else if (Offsets.size() != Lengths.size()) {
-    errs() << "error: number of -offset and -length arguments must match\n";
+    errs() << "error: number of -offset and -length arguments must match.\n";
     return true;
   }
   for (unsigned I = 0, E = Offsets.size(), CodeSize = Code->getBufferSize();
@@ -296,16 +296,12 @@ static bool fillRanges(MemoryBuffer *Code,
     }
     if (!EmptyLengths)
       Length = Lengths[I];
-    if (Length == 0) {
-      errs() << "error: length should be at least 1\n";
-      return true;
-    }
     if (Offset + Length > CodeSize) {
       errs() << "error: invalid length " << Length << ", offset + length ("
-             << Offset + Length << ") is outside the file\n";
+             << Offset + Length << ") is outside the file.\n";
       return true;
     }
-    Ranges.push_back(tooling::Range(Offset, Length - 1));
+    Ranges.push_back(tooling::Range(Offset, Length));
   }
   return false;
 }