[clang] [libclang/python] Move SPELLING_CACHE into CodeCompletion (PR #177586)

[Vlad Serebrennikov via cfe-commits]

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@@ -3149,6 +3073,107 @@ def __str__(self) -> str:
     VERTICAL_SPACE = 20
 
 
+class CompletionChunk:
+    class SpellingCacheAlias:
+        """
+        A temporary utility that acts as an alias to CompletionChunk.SPELLING_CACHE.
+        This will be removed without deprecation warning in a future release.
+        Please do not use it directly!
+        """
+
+        deprecation_message = (
+            "'SPELLING_CACHE' has been moved into the scope of 'CompletionChunk' "
+            "and adapted to use 'CompletionChunkKind's as keys instead of their "
+            "enum values. Please adapt all uses of 'SPELLING_CACHE' to use "
+            "'CompletionChunk.SPELLING_CACHE' instead. The old 'SPELLING_CACHE' "
+            "will be removed in a future release."
+        )
+
+        def __getitem__(self, value: int):
+            warnings.warn(self.deprecation_message, DeprecationWarning)
+            return CompletionChunk.SPELLING_CACHE[CompletionChunkKind.from_id(value)]
+        
+        def __contains__(self, value: int):
+            warnings.warn(self.deprecation_message, DeprecationWarning)
+            return CompletionChunkKind.from_id(value) in CompletionChunk.SPELLING_CACHE
----------------
Endilll wrote:

I think replicating the behavior `__getitem__` and `__contains__` is enough. We can handle the rest by throwing an error from `__getattr__`.

https://github.com/llvm/llvm-project/pull/177586