comments

diff --git a/doc/todo/add_xxHash_backend/comment_5_ad6f50e7d27d31028c81a4899f91f223._comment b/doc/todo/add_xxHash_backend/comment_5_ad6f50e7d27d31028c81a4899f91f223._comment
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+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 5"""
+ date="2025-09-24T16:30:12Z"
+ content="""
+This is a bug in your program. It is generating a
+key using the XH3 backend, rather than the XXH3 backend.
+
+       [2025-09-24 12:29:41.565937669] (Annex.ExternalAddonProcess) /home/joey/bin/git-annex-backend-XXH3[1] <-- GENKEY .git/annex/othertmp/ingest-bar89415-0
+       [2025-09-24 12:29:41.568293334] (Annex.ExternalAddonProcess) /home/joey/bin/git-annex-backend-XXH3[1] --> GENKEY-SUCCESS XH3-s30--88ad06d188b880a1
+
+When git-annex later wants to do something that that key,
+it expects to find a git-annex-backend-XH3 program.
+
+This change will fix it:
+
+       - hashtype="${0##*git-annex-backend-X}"
+       + hashtype="${0##*git-annex-backend-}"
+
+Once you have the program working, we can add it to the list of external
+backends.
+"""]]

diff --git a/doc/todo/add_xxHash_backend/comment_6_6889f05d633cb340046c9d4796735a57._comment b/doc/todo/add_xxHash_backend/comment_6_6889f05d633cb340046c9d4796735a57._comment
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+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 6"""
+ date="2025-09-24T16:39:02Z"
+ content="""
+I am inclined to keep this todo open despite external backend
+programs existing, because it would be nice to have xxHash in
+git-annex natively due to its speed.
+
+I found this haskell library which includes xxh3
+and which would be easy to add as a git-annex dependency,
+although it would need to be gated behind a build flag for now:
+<https://hackage.haskell.org/package/xxhash-ffi>
+
+(Since that library uses Hashable, it generates an Int for the hash.
+This seems to limit it to be used on 64 bit platforms. 
+<https://github.com/haskell-haskey/xxhash-ffi/issues/6>
+The lower-level Data.Digest.XXHash.FFI.C uses CULLong so will work on 32
+bit.)
+"""]]