A pass over the content at startup writes three widths per picture into a cache
outside the site root, named by the source's content hash and the width (ADR-0042).
Idempotent by construction: a rerun stats and skips, an edited picture takes a new
name, and nothing stale can be served under an old one. Restarting the evidence
site made 0 derivatives the second time, as it should.
Ahead of the request rather than during it, because resampling is felt and there is
no page cache yet to hide it. Outside the site root, because the engine reads that
directory and must not leave generated files in somebody's content git — a lost
cache costs one startup pass and no correctness.
Markup now carries the original as src, the derivatives as srcset closed by the
original at its own width, and width/height from the original — which retires most
of the latent row about the output floor; only a gallery's alt is still empty, and
a filename cannot supply that.
Two things the work itself decided:
`Fragment.Items` became `Fragment.Pictures`, ADR-0037's own revisit trigger. Items
had one consumer, so widening it beat adding a second list beside it.
"A browser can show it" and "we can resample it" are different questions, and
conflating them nearly deleted content: an SVG has no decoder here, so a single
predicate would have dropped SVGs from galleries silently. Undecodable and
unsupported pictures are now rendered as they are, without a size or a srcset.
A feature now learns which bundle is rendering: render.Bundle puts an Origin —
the bundle's directory plus the rooted fs.FS — on the parse context, and
render.OriginFrom reads it back. Available while parsing, not while rendering,
which decides where a feature does its filesystem work: goldmark hands the
context to a block parser and not to a node renderer, so gallery gathers its
filenames at parse time and carries them on the node.
Reads stay inside the site root because Origin passes the fs.FS rather than a
path to join (ADR-0031).
Fragment{Args, Items} lands with it (ADR-0037), so figure's template now reads
.Args.src. Authored arguments and engine-gathered items stay in separate fields:
a src argument beside a src the engine found would otherwise silently pick one.
A gallery is pictures beside the bundle, in filename order, skipping
subdirectories and anything a browser cannot show. Filename order is what makes
the sparse numeric-prefix convention work without numbers in URLs (ADR-0016).
New latent row: the reference theme's images carry no width/height and a
gallery's carry no alt, which is below the output floor conventions.md states.
Nothing can supply either yet — dimensions need the image read, and a filename is
not alt text. Queue 13 computes dimensions and brings structured items with it.
A call is `{{< name key="value" >}}` alone on a line, parsed by a goldmark block
parser into an AST node and rendered by executing a theme template of that name
(ADR-0036). `figure` ships; `include` and `gallery` need the including bundle's
directory, which the parser does not carry yet, so they wait.
The layering did the design work here. internal/render may not import
internal/ext, so render.New takes a callback that receives a Partial and returns
Markdown extensions, and cmd/khosra/wire.go holds the only list of enabled
features. Empty that list and the engine still builds and serves — which is the
property extensions.md says the contract should have.
Raw HTML stays disabled. An author's text reaches a page only as arguments that
html/template escapes in context, which the real binary shows: a hostile alt
becomes <script> and src="javascript:…" becomes #ZgotmplZ. Getting
contextual escaping from the standard library rather than writing it is the whole
reason a fragment renders this instead of the feature.
parseSet became variadic so the fragment set reuses it rather than growing a
second copy of the overlay logic; `Partial` takes map[string]string after the
advisory correctly flagged `any` as generality nothing had asked for.