[clang] Reapply "[APINotes] Prefer diff -u over diff -b" (PR #157894)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Aiden Grossman (boomanaiden154)

<details>
<summary>Changes</summary>

This reverts commit 8d35bcc52117b79517f518de952b4b50463de160.

This was causing failures on MacOS due to the head command there not supporting negative offsets. This patch fixes that by removing the call to HEAD and relaxing the requirements around removing the last line of the file.

---
Full diff: https://github.com/llvm/llvm-project/pull/157894.diff


2 Files Affected:

- (modified) clang/test/APINotes/yaml-roundtrip-2.test (+5-7) 
- (modified) clang/test/APINotes/yaml-roundtrip.test (+18-25) 


``````````diff
diff --git a/clang/test/APINotes/yaml-roundtrip-2.test b/clang/test/APINotes/yaml-roundtrip-2.test
index 63717bda7c099..26c5a73ad1083 100644
--- a/clang/test/APINotes/yaml-roundtrip-2.test
+++ b/clang/test/APINotes/yaml-roundtrip-2.test
@@ -1,11 +1,9 @@
 RUN: apinotes-test %S/Inputs/Frameworks/SimpleKit.framework/Headers/SimpleKit.apinotes > %t.result
-RUN: not diff -b -e %t.result %S/Inputs/Frameworks/SimpleKit.framework/Headers/SimpleKit.apinotes | FileCheck %s
-
-The `-e` option of `diff` is not implemented in the builtin diff, assume
-that we have a POSIX compatible diff when we have a shell.
-REQUIRES: shell
+RUN: not diff -u %S/Inputs/Frameworks/SimpleKit.framework/Headers/SimpleKit.apinotes %t.result | \
+RUN:   tail -n +4 | \
+RUN:   FileCheck %s --implicit-check-not="{{^\+}}" --implicit-check-not="{{^\-}}"
 
 We expect only the document markers to be emitted
 
-CHECK: 52d
-CHECK: 1d
+CHECK: +---
+CHECK: +...
diff --git a/clang/test/APINotes/yaml-roundtrip.test b/clang/test/APINotes/yaml-roundtrip.test
index f69038ca828b1..355596ef8e93b 100644
--- a/clang/test/APINotes/yaml-roundtrip.test
+++ b/clang/test/APINotes/yaml-roundtrip.test
@@ -1,30 +1,23 @@
 RUN: apinotes-test %S/Inputs/Frameworks/Simple.framework/Headers/Simple.apinotes > %t.result
-RUN: not diff -b %S/Inputs/Frameworks/Simple.framework/Headers/Simple.apinotes %t.result | FileCheck %s
-
-Avoid Windows as the diff output differs due to line-endings and different diff
-implementations.
-UNSUPPORTED: system-windows
+RUN: not diff -u %S/Inputs/Frameworks/Simple.framework/Headers/Simple.apinotes %t.result | \
+RUN:   tail -n +5 | \
+RUN:   FileCheck %s --implicit-check-not="{{^\+}}" --implicit-check-not="{{^\-}}"
 
 We expect only the nullability to be different as it is canonicalized during the
 roudtrip.
 
-CHECK:      7c8
-CHECK-NEXT: <         Nullability:     N
-CHECK-NEXT: ---
-CHECK-NEXT: >         Nullability:     Nonnull
-CHECK-NEXT: 13c14
-CHECK-NEXT: <         Nullability:     O
-CHECK-NEXT: ---
-CHECK-NEXT: >         Nullability:     Optional
-CHECK-NEXT: 19c20
-CHECK-NEXT: <         Nullability:     U
-CHECK-NEXT: ---
-CHECK-NEXT: >         Nullability:     Unspecified
-CHECK-NEXT: 25c26
-CHECK-NEXT: <         Nullability:     S
-CHECK-NEXT: ---
-CHECK-NEXT: >         Nullability:     Unspecified
-CHECK-NEXT: 28c29
-CHECK-NEXT: <         Nullability:     Scalar
-CHECK-NEXT: ---
-CHECK-NEXT: >         Nullability:     Unspecified
+CHECK:      -        Nullability:     N
+CHECK-NEXT: +        Nullability:     Nonnull
+CHECK:      -        Nullability:     O
+CHECK-NEXT: +        Nullability:     Optional
+CHECK:      -        Nullability:     U
+CHECK-NEXT: +        Nullability:     Unspecified
+CHECK:      -        Nullability:     S
+CHECK-NEXT: +        Nullability:     Unspecified
+CHECK:      -        Nullability:     Scalar
+CHECK-NEXT: +        Nullability:     Unspecified
+
+# The roundtrip will add document markers. It is hard to remove the last line of the
+# file in a cross-platform manner, so just assert it here to avoid a test failure due
+# to the implicit check not.
+# CHECK: +

``````````

</details>


https://github.com/llvm/llvm-project/pull/157894