diff options
author | Florian Klink <flokli@flokli.de> | 2024-03-01T08·56+0200 |
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committer | clbot <clbot@tvl.fyi> | 2024-03-03T16·52+0000 |
commit | 65a810fc0b12e754af47864ab3b9d4b5756cde15 (patch) | |
tree | ec69ccf0de3dcd53dc47748f8f2a6a649a85ad48 /tvix/docs/differences-drv-paths.md | |
parent | 6bdaebcb55eef5663f93dbbc8de6a48b459a10c0 (diff) |
feat(tvix/docs): switch to mdbook r/7645
Some of the docs are still outdated (like architecture and drv path inconsistencies). Change-Id: I7a6afceb008ef4cd19a764dd6c637b39fa842a2e Reviewed-on: https://cl.tvl.fyi/c/depot/+/11072 Autosubmit: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Reviewed-by: edef <edef@edef.eu>
Diffstat (limited to 'tvix/docs/differences-drv-paths.md')
-rw-r--r-- | tvix/docs/differences-drv-paths.md | 46 |
1 files changed, 0 insertions, 46 deletions
diff --git a/tvix/docs/differences-drv-paths.md b/tvix/docs/differences-drv-paths.md deleted file mode 100644 index e93131aa57e2..000000000000 --- a/tvix/docs/differences-drv-paths.md +++ /dev/null @@ -1,46 +0,0 @@ ---- -title: ".drvPath inconsistencies" -author: - - tazjin - - flokli -email: - - tazjin@tvl.su - - flokli@flokli.de -lang: en-GB ---- - -# Why .drvPath differs between Nix and Tvix - -Nix and Tvix currently use a different approach when it comes to tracking input -references, in order to build the right dependencies in advance. -Nix is using string contexts, whereas Tvix is doing reference scanning [^inbox-drvpath]. - -There are some real-life cases, for example during nixpkgs bootstrapping, where -multiple different fixed-output derivations are written to produce the same -hash. - -For example, bootstrap sources that are downloaded early are fetched using -a special "builder hack", in which the `builder` field of the derivation is -populated with the magic string `builtin:fetchurl` and the builder itself will -perform a fetch, with everything looking like a normal derivation to the user. - -These bootstrap sources are later on defined *again*, once `curl`is available, -to be downloaded using the standard pkgs.fetchtarball mechanism, but yielding -the *same* outputs (as the same files are being fetched). - -In our reference scanning implementation, this output scanning of FOD will -cause the path of the *first* derivation producing the given fixed output to be -stored in the `inputDrvs` field of the derivation, while Nix will point to the -derivation that was actually used. - -This doesn't cause any differences in the calculated *output paths*, as paths to -fixed-output derivations are replaced with a special -`fixed:out:${algo}:${digest}:${fodPath}` string that doesn't contain the "path -to the wrong derivation" anymore. - -As we haven't fully determined if our reference scanning approach is gonna work, -and comparing output paths is sufficient to determine equality of the build -instructions, this is left as a future work item. - - -[^inbox-drvpath]: https://inbox.tvl.su/depot/20230316120039.j4fkp3puzrtbjcpi@tp/T/#t |