format: a CSV quotes the fields that need it, and you choose which

[donislawdev]

Adds quote_style to the csv format, taking minimal, all or none.

This is a breaking change under D11 and it is deliberate. The default is
minimal, so the description column - quoted on every row until now - is
quoted only when it carries the separator. Measured on a 4 kB table at seed 7
before the change: 9 of 44 rows carry a description with no separator,
because the phrase is three to seven words and drops a separator every third
one. Those nine lose their quotes. Sizes are unchanged and every reader that
took these files still takes them.

The values are the RFC 4180 vocabulary and nothing outside it. A fourth name
preserving today's bytes was rejected: the release this belongs to closes with
a major bump either way, so a clean vocabulary costs nothing now and a fourth
name would have been carried forever.

Two things that are not obvious from the list of values

none changes the CONTENT, not only the punctuation. An unquoted field
cannot hold a separator without ending early, so the description stops carrying
one - in the phrase and in the padding both. A value that only removed the
quotes would produce a ragged row at exactly the right size, which is the
defect this tool offers deliberately elsewhere.

The closing row is built to the byte, so under minimal the decision to
quote changes the length that the decision depends on. Measured over 59
sizes: the padding first carries a separator at 30 B of description, so the
ambiguous band is two sizes per dialect. Resolved by MEASURING - the quoted
length is built first, and if it carries the separator the quotes are earned,
otherwise the description is rebuilt to the full room with the separator
withheld. A threshold constant was rejected as arithmetic that would have to
keep agreeing with the bytes beside it.

The rest

The floor moves with the setting, the way the dialect already does: 115 B
rather than 117 under minimal and none, 139 B under all. Twelve
combinations, eight distinct floors, all measured with the binary.

all quotes the header too, because a header is a row of fields and a writer
told to quote everything quotes those as well. Leaving it bare would have left
the structural checker with an "except the first row" exception, which is where
a defect hides.

The structural checker is now told the style and judges it, with negative
controls in both directions. That matters more here than for the other axes:
all three styles produce a well formed file, so nothing about the table gives
the style away and a rubber stamp would have been silent.

Verified

• 1152 files swept over every size from 115 to 260 B across three styles
  and two delimiters - exact size, six columns under Python's csv module,
  quoting matching the style, no needless quote under minimal.
• All 48 dialect combinations through the structural checker, plus seven
  negative controls.
• LibreOffice Calc headless reads all three variants as six columns on
  every row, which closes D4 for the new values. A spreadsheet rather than a
  parser, so it answers a question our oracles cannot.
• 16 of 16 mutations caught.

Two of those mutations came back NOT CAUGHT at first, and the fault was in
the guard rather than the code: both only shift the ANNOUNCED floor, which is
invisible everywhere else because Shortest is the worst draw and a real row
sits some forty bytes under it. The only handle is the count of distinct
floors, and it was written as six where the axes make eight.

An earlier version of the dialect guard also asserted that the closing row
always carries a separator inside its quotes. Under all it need not, because
all quotes regardless - the guard assumed a state it does not always reach.
It now walks a band of 24 sizes and asserts it reached one.

Full suite, preflight --quick (12 of 12, including the three CI-only checks)
and pinned staticcheck v0.8.1 are all green locally.

🤖 Generated with Claude Code