[clang] [Format] Do not crash on non-null terminated strings (PR #131299)

[Ilya Biryukov via cfe-commits]

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@@ -2382,14 +2382,20 @@ size_t SourceManager::getDataStructureSizes() const {
 
 SourceManagerForFile::SourceManagerForFile(StringRef FileName,
                                            StringRef Content) {
+  // We copy to `std::string` for Context instead of StringRef because the
+  // SourceManager::getBufferData() works only with null-terminated buffers.
+  // And we still want to keep the API convenient.
+  ContentBuffer = Content.str();
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ilya-biryukov wrote:

> I mainly think about my battery, when I code while being mobile.

But this extra copy is likely a really-really small portion of the reformatting cost. Performance and battery go together here.
Is there anything I'm missing why it would not be the case?

https://github.com/llvm/llvm-project/pull/131299