Fix selective formatting of ObjC scope

[acoomans]

Summary

ObjC scopes gets formatted beyond the @end directive, when formatting specific lines (clang-format -lines=x:x).

This changeset fixes formatting of @end the same way that r_braces are.
E.g: running clang-format -lines=3:3 on (note the extra white space in front of @optional):

@protocol A
 @optional
// comment
- (void)f;
@end
MACRO

would be formatted:

@protocol A
 @optional
 // comment
 - (void)f;
@end
MACRO

instead of:

@protocol A
 @optional
 // comment
 - (void)f;
 @end
 MACRO

Initial bug report / feature request: https://bugs.llvm.org/show_bug.cgi?id=37975

[acoomans]

I probably don't need a unit test AND a lit test, but I'm unsure which one is best here. Any suggestion?

lib/Format/UnwrappedLineFormatter.cpp

1045–1047

Note to self: change the style to match PreviousRBrace

[acoomans]

@jolesiak let me know what you think

[jolesiak]

Nice! That looks very promising.

It still fails when we pass a longer range (maybe mimicking PreviousRBrace will help), e.g.:
Base code:

@protocol A
 @optional
// comment
- (void)f;
@end
MACRO

formatted with clang-format -lines=3:6 file.m gives:

@protocol A
 @optional
 // comment
 - (void)f;
 @end
 MACRO

This is not happening for Cpp, e.g.:
Base code:

class A {
 void f ();
// comment
void g ();
};
MACRO

running clang-format -lines=3:6 file.cpp gives:

class A {
 void f ();
 // comment
 void g ();
};
MACRO

I think it would be good to add all these tests to unit tests, but I see that an interface to pass line ranges is not very pleasant.

lib/Format/UnwrappedLineFormatter.cpp

for (const AnnotatedLine *Line =
     // remaining file if it currently missing a closing brace.
     bool PreviousRBrace =
         PreviousLine && PreviousLine->startsWith(tok::r_brace);
     bool ContinueFormatting =
         TheLine.Level > RangeMinLevel ||
         (TheLine.Level == RangeMinLevel && !PreviousRBrace &&
          !TheLine.startsWith(tok::r_brace));
 
+    if (TheLine.First->Next && TheLine.First->Next->Tok.isObjCAtKeyword(tok::objc_end)) {
+      ContinueFormatting = false;
+    }
+
     bool FixIndentation = (FixBadIndentation || ContinueFormatting) &&
                           Indent != TheLine.First->OriginalColumn;
     bool ShouldFormat = TheLine.Affected || FixIndentation;
     // We cannot format this line; if the reason is that the line had a
     // parsing error, remember that.
     if (ShouldFormat && TheLine.Type == LT_Invalid && Status) {
       Status->FormatComplete = false;
       Status->Line =

test/Format/adjust-indent-objc.m

+// RUN: grep -Ev "// *[A-Z-]+:" %s | clang-format -lines=4:4 \
+// RUN:   | FileCheck -strict-whitespace %s
+
+@protocol A
+// CHECK: @protocol A
+ @optional
+// CHECK: {{^ @optional}}
+- (void)f;
+// CHECK: {{^ - \(void\)f;}}
+@end
+// CHECK: {{^@end}}
+MACRO
+// CHECK: {{^MACRO}}
 No newline at end of file

unittests/Format/FormatTestSelective.cpp

EXPECT_EQ(
              "  h();\n"
              "}\n"
              "\n"
              "void g() {\n" // Make sure not to format this.
              "}",
              15, 0));
 }
 
+TEST_F(FormatTestSelective, StopFormattingWhenLeavingObjCScope) {
+    EXPECT_EQ("@protocol A\n"
+              " - (void)f;\n"
+              " - (void)g;\n"
+              "@end\n"
+              "MACRO",
+              format("@protocol A\n"
+                     " - (void)f;\n"
+                     "- (void)g;\n"  // Format here.
+                     "@end\n"
+                     "MACRO",
+                     25, 0));
+}
+
 TEST_F(FormatTestSelective, SelectivelyRequoteJavaScript) {
   Style = getGoogleStyle(FormatStyle::LK_JavaScript);
   EXPECT_EQ(
       "var x = \"a\";\n"
       "var x = 'a';\n"
       "var x = \"a\";",
       format("var x = \"a\";\n"
              "var x = \"a\";\n"