[clang] [clang-format] Add --fail-on-incomplete-format. (PR #84346)

[Owen Pan via cfe-commits]

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@@ -0,0 +1,5 @@
+// RUN: cat %s | not clang-format --fail-on-incomplete-format | FileCheck %s
+// RUN: cat %s | clang-format | FileCheck %s
+int a([) {}
+
+// CHECK: int a([) {}
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owenca wrote:

> Done. It took me quite a while but `-style=LLVM` is also required as the .clang-format in the parent directory sets DisableFormat to true. Before I didn't notice because the `cat %s | clang-format` was bypassing the lookup for the config file.

It seems that `-style=LLVM` is needed whether the input comes from the stdin or a file.

https://github.com/llvm/llvm-project/pull/84346