THE FOLD / LOOT / THE VAULT / THE REPRODUCIBLE BUILD
THE REPRODUCIBLE BUILD
they prove two builders agreed, not that either was right
1 WHAT IT IS · WHAT IT DOES · FACT OR FICTION
Build the same source twice and get the same bytes. It sounds like the default and it is not — a build is a program with the clock, the filesystem and the scheduler as hidden inputs.
LIT verified live, exhaustively. 4 sources of nondeterminism, every one of the 16 combinations tested. Only 2 produce byte-identical output and 14 differ. 3 of the factors break reproducibility — an embedded timestamp, an absolute build path, hash-map iteration order — and 1 does not: parallel job scheduling, because the link step does not care what order it was handed things.
LIT verified live, exhaustively. 4 sources of nondeterminism, every one of the 16 combinations tested. Only 2 produce byte-identical output and 14 differ. 3 of the factors break reproducibility — an embedded timestamp, an absolute build path, hash-map iteration order — and 1 does not: parallel job scheduling, because the link step does not care what order it was handed things.
2 HOW IT WAS WEAVED · AI + HUMAN
Reproducible builds are how you tell whether a binary corresponds to the source it claims; Debian and Bazel both treat it as a correctness property rather than a nicety.
AVAN (AI) included a factor that does not break it. 2 identical configurations rather than 1 is the whole finding: nondeterminism in the process is not the same as nondeterminism in the output, and telling those apart is the actual work.
AVAN (AI) included a factor that does not break it. 2 identical configurations rather than 1 is the whole finding: nondeterminism in the process is not the same as nondeterminism in the output, and telling those apart is the actual work.
3 ONE DIMENSION
Sixteen configurations, two of them reproducible.
4 TWO DIMENSIONS · INTERACTIVE
Switch each factor on and off.
5 THREE DIMENSIONS + AVAN’S INVERSE
The green forward object: the same source, twice.
AVAN’s addition (the inverse-companion): the forward reading is that reproducible builds prove the binary matches the source. The inverse is that they prove no such thing on their own — they prove two builders agreed. A compiler with a backdoor reproduces perfectly; every rebuild returns the same compromised bytes, and the check passes. Read backwards, reproducibility does not establish that a binary is trustworthy, only that trusting it is a decision you have to make once rather than every time, which is a smaller and more honest claim than the one usually made for it.
LIT 4 sources of nondeterminism across all 16 combinations leave only 2 producing byte-identical output and 14 differing, because 3 of the factors break reproducibility - an embedded timestamp, an absolute build path, hash-map iteration order - and 1 does not: parallel job scheduling, since the link step does not care what order it was handed things
FIG Reproducible builds are how you tell whether a binary corresponds to the source it claims; Debian and Bazel both treat it as a correctness property rather than a nicety. AVAN included a factor that does NOT break it. 2 identical configurations rather than 1 is the whole finding: nondeterminism in the process is not the same as nondeterminism in the output, and telling those apart is the actual work.
FIG Reproducible builds are how you tell whether a binary corresponds to the source it claims; Debian and Bazel both treat it as a correctness property rather than a nicety. AVAN included a factor that does NOT break it. 2 identical configurations rather than 1 is the whole finding: nondeterminism in the process is not the same as nondeterminism in the output, and telling those apart is the actual work.
◆ sealed .dlw.fold → folded to ROOT_0 · a sphere of THE VAULT · David Lee Wise (ROOT0), with AVAN