[clang-format] Fix a bug in IndentExternBlock: NoIndent (#75731)

Fixes #36620.
Fixes #75719.

Author: owenca

clang/lib/Format/Format.cpp

@@ -1315,7 +1315,6 @@ static void expandPresetsBraceWrapping(FormatStyle &Expanded) {
     Expanded.BraceWrapping.AfterStruct = true;
     Expanded.BraceWrapping.AfterUnion = true;
     Expanded.BraceWrapping.AfterExternBlock = true;
-    Expanded.IndentExternBlock = FormatStyle::IEBS_AfterExternBlock;
     Expanded.BraceWrapping.SplitEmptyFunction = true;
     Expanded.BraceWrapping.SplitEmptyRecord = false;
     break;
@@ -1335,7 +1334,6 @@ static void expandPresetsBraceWrapping(FormatStyle &Expanded) {
     Expanded.BraceWrapping.AfterStruct = true;
     Expanded.BraceWrapping.AfterUnion = true;
     Expanded.BraceWrapping.AfterExternBlock = true;
-    Expanded.IndentExternBlock = FormatStyle::IEBS_AfterExternBlock;
     Expanded.BraceWrapping.BeforeCatch = true;
     Expanded.BraceWrapping.BeforeElse = true;
     Expanded.BraceWrapping.BeforeLambdaBody = true;
@@ -1350,7 +1348,6 @@ static void expandPresetsBraceWrapping(FormatStyle &Expanded) {
     Expanded.BraceWrapping.AfterObjCDeclaration = true;
     Expanded.BraceWrapping.AfterStruct = true;
     Expanded.BraceWrapping.AfterExternBlock = true;
-    Expanded.IndentExternBlock = FormatStyle::IEBS_AfterExternBlock;
     Expanded.BraceWrapping.BeforeCatch = true;
     Expanded.BraceWrapping.BeforeElse = true;
     Expanded.BraceWrapping.BeforeLambdaBody = true;
@@ -1375,7 +1372,6 @@ static void expandPresetsBraceWrapping(FormatStyle &Expanded) {
         /*SplitEmptyFunction=*/true,
         /*SplitEmptyRecord=*/true,
         /*SplitEmptyNamespace=*/true};
-    Expanded.IndentExternBlock = FormatStyle::IEBS_AfterExternBlock;
     break;
   case FormatStyle::BS_WebKit:
     Expanded.BraceWrapping.AfterFunction = true;
@@ -1909,7 +1905,6 @@ FormatStyle getMicrosoftStyle(FormatStyle::LanguageKind Language) {
   Style.BraceWrapping.AfterObjCDeclaration = true;
   Style.BraceWrapping.AfterStruct = true;
   Style.BraceWrapping.AfterExternBlock = true;
-  Style.IndentExternBlock = FormatStyle::IEBS_AfterExternBlock;
   Style.BraceWrapping.BeforeCatch = true;
   Style.BraceWrapping.BeforeElse = true;
   Style.BraceWrapping.BeforeWhile = false;

clang/unittests/Format/FormatTest.cpp

@@ -4571,6 +4571,13 @@ TEST_F(FormatTest, IndentExternBlockStyle) {
                "}",
                Style);
 
+  Style.BreakBeforeBraces = FormatStyle::BS_Allman;
+  verifyFormat("extern \"C\"\n"
+               "{\n"
+               "int i;\n"
+               "}",
+               Style);
+
   Style.BreakBeforeBraces = FormatStyle::BS_Custom;
   Style.BraceWrapping.AfterExternBlock = true;
   Style.IndentExternBlock = FormatStyle::IEBS_Indent;