[clang] [clang-scan-deps] Expand response files before the argument adjuster (PR #89950)

[Alexandre Ganea via cfe-commits]

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@@ -0,0 +1,36 @@
+// Check that the scanner can adjust arguments by reading .rsp files in advance.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: sed -e "s|DIR|%/t|g" %t/cdb.json.template > %t/cdb.json
+// RUN: echo /Fo%t/tu.obj >> %t/args_nested.rsp
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aganea wrote:

Can you elaborate please on "I tried playing around with response files and they don't play well with newlines"?
Things we working on my end (empty lines in .rsp files). Also, Unreal Engine generates .rsp files with each argument on a new line, so if you're seeing any issues there we shall fix them.

https://github.com/llvm/llvm-project/pull/89950