[adamzochowski]

That is something I wanted to know, does IPFS guarantee that same two files have same two IPFS URLs / hash links?

Otherwise, someone sharing same data again, because it will be in different IPFS folder won't be actually discoverable as same data.

[hot_gril]

Yes, a file's hash is only based on its contents. The way I understand it, a file doesn't really live in a directory, it's more like a directory (which is a kind of file itself) references files. So the same file can be in two directories, yet it'll have the same URL/hash. And if you "add" files to a directory, you're really uploading a separate copy of the dir that'll have a different hash.

I checked myself on this, but someone else might want to check me cause I'm not an expert.

[wuiheerfoj]

This is generally true, though it’s possible to encode the same data into a slightly different shaped DAG to optimise for eg video streaming performance afaiu (balanced vs imbalanced). UnixFS vs raw bytes may also be different but I’m not 100%

[fwip]

Yes, IPFS hashes individual "blocks" (pieces) of files. If two files have the same content, they will share block hashes.

[ranger_danger]

Basically it depends on specific settings that can be changed in the client as to how the individual block pieces are encoded and therefore what the resulting hash ends up being. So no there's no inherent guarantee but you may get lucky with some copies of the same file.

[mikegreenberg]

Caveat: The other comments mention the file's contents being the only dependency on the hash, but the algo used to hash would also need to be the same. If the hash algo changes in two cases, the same content would have a different hash in those two cases.

[hot_gril]

In this case, would pinning the file make it accessible from either hash? I'd expect it to, but idk, I've only ever seen sha256 hashes on IPFS.