Tom Lane 07eee5a0dc Create a new type category for "internal use" types. ... Historically we've put type "char" into the S (String) typcategory, although calling it a string is a stretch considering it can only store one byte. (In our actual usage, it's more like an enum.) This choice now seems wrong in view of the special heuristics that parse_func.c and parse_coerce.c have for TYPCATEGORY_STRING: it's not a great idea for "char" to have those preferential casting behaviors. Worse than that, recent patches inventing special-purpose types like pg_node_tree have assigned typcategory S to those types, meaning they also get preferential casting treatment that's designed on the assumption that they can hold arbitrary text. To fix, invent a new category TYPCATEGORY_INTERNAL for internal-use types, and assign that to all these types. I used code 'Z' for lack of a better idea ('I' was already taken). This change breaks one query in psql/describe.c, which now needs to explicitly cast a catalog "char" column to text before concatenating it with an undecorated literal. Also, a test case in contrib/citext now needs an explicit cast to convert citext to "char". Since the point of this change is to not have "char" be a surprisingly-available cast target, these breakages seem OK. Per report from Ian Campbell. Discussion: https://postgr.es/m/2216388.1638480141@sss.pgh.pa.us		2021-12-11 14:10:51 -05:00
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citext.sql	Create a new type category for "internal use" types.	2021-12-11 14:10:51 -05:00