Order of tags: should TaggedOperation(op, "tag1", "tag2")==TaggedOperation(op, "tag2", "tag1")?

[babacry]

Now

TaggedOperation(op, "tag1", "tag2")!=TaggedOperation(op, "tag2", "tag1")
and
TaggedOperation(op, "tag1", "tag2")==TaggedOperation(op, "tag1", "tag2")

wonder why does the order of tags matter? if not, should serialization/deserialization take tag sorting into consideration?

[mhucka]

Discussed in Cirq Cynq 2025-04-30: trying to recall the reasons for the current design (which is a tuple, not a set), the sense is that it was probably created at a time when people weren't thinking about multiple tags. This is likely not an intentional behavior, but rather a bug.

[babacry]

Some context: I am writing some tag transformers in #7306, in tests, I need to do some extra steps to compare TaggedOperation, it's not a blocker for me, but looks like it's a bug, so I am asking here.