cpybuild record takes a --size and Built carries the field, but the publish job never passes it, so every one of the ten entries in images/cpython.lock.json says "size": 0.
"jit": {
"arm64": {
"digest": "sha256:93a9f2371238b477a018714f63b80a6371589e5dd7b8055f895d596433f51097",
"built": "2026-08-29",
"size": 0
}
}A field that is always zero is worse than no field, because a reader who sees it reasonably assumes it means something. Either fill it in or take it out, and filling it in is worth more: the README currently says the release image is "around 700 MB unpacked on arm64" because I measured one by hand, and a number in the lockfile would be measured on every build and would show the day one of them doubles.
The thing to be careful about is which size. docker buildx imagetools inspect reports the compressed size of the manifest and its layers, which is roughly a third of what docker images shows and is not the number a reader cares about when they are deciding whether to pull one. Whichever it is, the field should say so in its name.
Small and not on anybody's path. Worth doing next time the publish job is open for another reason.
cpybuild recordtakes a--sizeandBuiltcarries the field, but the publish job never passes it, so every one of the ten entries inimages/cpython.lock.jsonsays"size": 0.A field that is always zero is worse than no field, because a reader who sees it reasonably assumes it means something. Either fill it in or take it out, and filling it in is worth more: the README currently says the release image is "around 700 MB unpacked on arm64" because I measured one by hand, and a number in the lockfile would be measured on every build and would show the day one of them doubles.
The thing to be careful about is which size.
docker buildx imagetools inspectreports the compressed size of the manifest and its layers, which is roughly a third of whatdocker imagesshows and is not the number a reader cares about when they are deciding whether to pull one. Whichever it is, the field should say so in its name.Small and not on anybody's path. Worth doing next time the publish job is open for another reason.