# 260802 — how CB-RES-0006 was conducted

Unpolished trail for `research/CB-RES-0006-render-port.md`, per
InnerLoop §Step 2 documentation requirement.

## What was measured vs cited

**Everything quoted is measured.** No line count in the survey comes from
a README, a crates.io page, or memory. Method: a scratch cargo crate per
candidate, `cargo add`, then `cargo tree --edges normal --prefix none`
over the resolved graph, then `\n` counted in every `.rs` file of the
vendored source under `~/.cargo/registry/src/*/`.

That method is copied out of `tools/dep-weight.py` rather than
re-invented, because the survey's whole purpose is to subtract candidate
sizes from a budget produced by that tool, and two methods produce two
numbers that cannot be subtracted.

Scripts: `$CLAUDE_JOB_DIR/tmp/survey/{measure,breakdown,gap}.py`.
Deliberately not committed — a throwaway probe promoted to a repo tool is
how the second-use rule gets broken by accident. If a later pass needs
these numbers refreshed, it should re-derive them, and the fact that it
costs ten minutes is a feature.

## Dead ends and corrections during the survey

**First reading was on the wrong axis.** The initial run reported headline
totals: `egui+eframe` 2,946,121, `ratatui+crossterm` 1,146,363,
`macroquad` 480,729. Those are the numbers a survey normally quotes and
they are the wrong ones — AM-4a charges what a candidate *adds* to a graph
that already holds 23 crates. Recomputed as marginal against the real
base. For `macroquad` the difference is negligible (480,729 → 480,501);
for `egui+eframe` it is 163,272 lines of overlap.

**A network 403 that was not a network failure.** `curl` to crates.io
returned 403; the sandbox looked like it was blocking egress. It was a
missing user-agent — crates.io rejects requests without one. Two further
probes (sparse index, static.crates.io) returned 200. Worth recording
because "the environment is blocking me" is a conclusion that ends
surveys, and it was wrong here by one header.

**Checked whether `cargo tree` was including non-host targets.** The
`ratatui` figure was dominated by `linux-raw-sys` (479,901) and looked
like it might be an all-platform artifact — a Windows-bindings inflation
of a Linux measurement. Re-ran with `--target x86_64-unknown-linux-gnu`:
identical, 1,146,363 both ways. The number is real, and `ratatui` really
does cost more than a 2D game framework.

**The proc-macro finding was not what the survey set out to look for.** It
came from asking why `syn` was the largest single entry in a
"shipped-runtime" figure. `--edges normal,no-proc-macro` answered it:
89,048 lines, 36.2%, none of which reaches a binary.

Order matters here, and it went the right way by luck rather than design:
the candidate measurements were complete *before* the instrument defect
was found, so the recommendation could be checked against the corrected
number instead of being derived from it. Had it gone the other way the
survey would have been unusable — a budget correction discovered while
looking for headroom is not evidence, whatever it says.

## What the survey did not do

- **It did not sample the region between 0 and 480,501 lines.** The
  candidate list was assembled from what one reaches for — modern GPU-era
  Rust GUI stacks — and every one of them landed two orders of magnitude
  over. The conclusion "no windowed toolkit fits" was therefore drawn from
  a sample that contained no small windowed toolkits. This is the gap the
  challenge (T02) attacks, and it is a real one.
- **It did not run any candidate.** No candidate was built, drawn with, or
  benchmarked. Per InnerLoop §Step 1 the comparisons here are dependency
  cost only; nothing in the survey claims one toolkit draws better than
  another, and no `better` verdict is available on that axis.
- **It did not measure the browser.** The HTML option is scored zero on
  AM-4a because AM-4a measures vendored Rust. What the browser costs on
  any other axis is unmeasured and the survey says so in §5.