vh
37d859c0fd
In-flight rewritten to what is actually live: design-dev's blur merge is HELD
at 5ded5ff awaiting his explicit 'merge it' ping (both panels dispatched 17:53,
unfolded), the redesign and thumbnails and dates are shipped, and the browser
suite is flaky under load and NOT fixed.
Two detail files added. The dates one is the reusable lesson: three plausible
proxies for a creation date were considered and one was nearly built, and the
real answer was a syscall away — the system already recorded what looked
unavailable. One of the rejected proxies was write-on-read, a shape this repo
had finished paying for hours earlier.
The flake entry is written as OPEN with its limits stated: three tests, two
real defects fixed, neither proven causal, and n=3 cannot show an improvement.
Recent decisions and Tried and abandoned preserved intact (49->51 by addition,
7 unchanged); the index is back under the soft cap at 141 lines from 285, all
of the reduction from settled history leaving the volatile section.
43 lines
2.1 KiB
Markdown
43 lines
2.1 KiB
Markdown
# Creation dates, and three guesses wearing a fact's clothes
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_2026-09-23 · booth_
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The operator asked for creation and update dates on booths. **Update** was
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already there — `landed_at`, the newest mtime among CONTENT excluding our own
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machinery. **Creation** had no honest source, and the interesting part is the
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three wrong answers.
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## Only 18 of 30 booths could state a creation time
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`.booth.json` carries a declared `created`, but it exists only for booths posted
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through the CLI since U5. Twelve live booths had nothing.
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## ⚠ Every convenient substitute was a GUESS PRESENTED AS A FACT
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- **Oldest content mtime** — wrong the moment an agent copies files with
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timestamps preserved (`cp -p`, `rsync -a`), which is common. It would report
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the SOURCE material's age as the booth's.
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- **Directory mtime** — that is "last thing added", i.e. `landed_at` under a
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second name. Two fields, one meaning, displayed as if they were different.
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- **Stamp a first-seen marker on read** — and this is the one worth flagging,
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because it is the same write-on-read shape that had *already* cost this
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service an hour that same day when the thumbnail cache aged the booth it
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cached ([[2026-09-23-the-cache-that-aged-the-thing-it-cached]]). A fix whose
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shape you just finished paying for is not a fix.
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## The answer was a fact the disk already held
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**ext4 records a real birth time.** CPython does not expose `st_birthtime` on
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Linux, but `statx(2)` does and glibc has wrapped it since 2.28, so
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`booth/birthtime.py` reads it through `ctypes`. Verified against `stat(1)` on
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live booths: **6 of 6 exact**, including every booth with no manifest.
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One rule for all thirty, which is what invariant 6 asks of anything statable in
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a line. `None` when the filesystem cannot say (tmpfs, NFS, an old kernel), and
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**None renders as nothing** — a blank is the honest output when nobody knows,
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and better than a plausible number.
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**The generalisable bit:** when a fact seems unavailable, check whether the
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system already records it before reaching for a proxy. Three plausible proxies
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were considered and one was nearly built; the real answer was a syscall away.
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