When (if ever) will HEAD~ and HEAD^ not be the same commit?

Question

Is there any situation in which HEAD~ and HEAD^ will not be the same commit? In a more general sense, is there any series of merges or other operations that will result in x~ not being the same thing as x^?

Answer 1

No, HEAD~ and HEAD^ are synonyms.

HEAD~ means HEAD~1 by definition.

HEAD~1 means HEAD^ by definition.

See git rev-parse --help for more information.