Answer architecture round 1: a module's reads sits on its index entry or, for a source without an index, in the load that walks it, the note names default modules, the shipped modules are listed by name, datafiles drops its unused base, and item 195 files the builtins' second parse

docs/comprehension-history.md

@@ -304,3 +304,29 @@ Junior A, decided by:
 - Locality, Shape: `node.go:23` `folder`: `put` and `putUnloaded` keep a name in one map, where `compileInto` and `unloadedCategory.load` kept it as a pair
 - Locality, Shape: `data.go:12` `loadSources`: one load path, where `config.load` forked and `loadShipped` was a second, panic-only pipeline
 - Shape: `data.go:81` `categorySite`: embeds `categoryAt`, where `unloadedCategory` repeated its fields
+
+## 2026-10-10T11:11:16Z, PR #203 at 421bb49, against bf1becb
+
+Ruling: worse
+
+| Seat | Navigation | Locality | Shape | Self-sufficiency | Overall |
+|---|---|---|---|---|---|
+| Mid A | same | worse | worse | same | worse |
+| Inherited architect | same | worse | worse | same | worse |
+
+Mid A, decided by:
+
+- Locality, Overall: `node.go:28` `folder.reads`: a third per-name map beside children and unloaded with no invariant tying it to them; every placement site must remember a separate setReads call (`data.go:36` addSource, `data.go:76` mergeFolder, `index.go:27` placeIndex)
+- Locality, Shape: `resolve.go:96` `withReads`: the manifest's reads travels through folder, categorySite.reads and templateSite.category to feed one error clause, four files to hold for one sentence of error text
+- Shape: `internal/datafiles/manifest.go:22` `Manifest.Reads`: reads as a load dependency the loader acts on, though it only feeds error text, and "reads" already means a template reading a name or column
+- Shape: `data/geo/SE/fs.go:2` `SE`: package names SE, US, en_US, sv_SE; in Modules SE.FS sits beside sv_SE.FS with nothing saying which is geography
+- Locality: `fejkdata.go:94` `New`: loads exactly what the options name, easier than the hidden config{shipped: true} default, though config.given brings back a smaller flag
+
+Inherited architect, decided by:
+
+- Locality, Shape, Overall: `node.go:27` `folder.reads`: a third per-name map that put and putUnloaded leave alone, so addSource, mergeFolder and placeIndex must each call setReads, and batch.load relies on placeIndex having done it; action at a distance for one error suffix
+- Locality: `resolve.go:94` `templateSite.withReads`: reads travels folder, categorySite.reads, a *categorySite per template, then withReads, four hops across three files
+- Shape: `data/geo/SE/fs.go:2` `SE`: bare package names SE and US do not say geography at WithDataFS(sv_SE.FS, SE.FS); the namespace-doubling rule lives only in README and test code
+- Shape, Self-sufficiency: `internal/datafiles/manifest.go:22` `Manifest.Reads`: suggests it drives loading though it only feeds withReads; "by default" needs README goal 9.2
+- Locality, Navigation: `data/modules.go:17` `Modules`: the hidden shippedFS default is gone; Modules lists the modules, errNoData names the fix, and the CLI loads data.Modules() in plain sight
+- Locality: `fejkdata.go:40` `config.given`: WithDataFS() with no arguments differs from no option, learnt only from its comment

docs/decisions.md

@@ -143,7 +143,7 @@ package under `data/` embeds its own files, and a library imports the packages i
 
 - One Go package per locale, one per country's `geo/` tree, and one for `misc`, all in the core's Go module. A package registers nothing when imported.
 - A bare `New()` loads no data and fails, naming the option to add. `WithoutShippedData` goes.
-- A data package's `FS` is an `fs.FS` passed to `WithDataFS`, as anyone's data is, and `New` takes several. A module carrying functions loads through an option of its own, so a data module that starts carrying functions breaks its users. Such a function reaches the randomness through an interface the root declares; `internal/drawstate`'s type stays internal.
+- A data package's `FS` is an `fs.FS` passed to `WithDataFS`, as anyone's data is, and `New` takes several. It is an exported `var FS embed.FS`, the shape `//go:embed` gives; a function returning it would guard only against a program reassigning a dependency of its own. A module carrying functions loads through an option of its own, so a data module that starts carrying functions breaks its users. Such a function reaches the randomness through an interface the root declares; `internal/drawstate`'s type stays internal.
 - A module names, in a manifest, every module it reads by default, directly or through another, so the first error names the whole set to import. A manifest is optional: a `--data-path` folder without one is a module. Nothing loads a default on its own.
 - A manifest names no fejkdata version, and `New` checks none: the shipped packages ship in the core's Go module, and a module from anyone else keeps loading across a minor or a patch, as the README's Versioning promises. The maintainer chose so on 2026-10-09.
 - In the CLI, a flag of its own says a `--data-path` replaces what it clashes with, so flags still go anywhere on the line. Data authors and hand fixture authors bench it.
@@ -582,7 +582,9 @@ when a source carries it.
 
 2026-09-24, Lilleman auf Larv; revised 2026-10-10, when the shipped data became Go packages.
 Serves goal 6.2. `sv_SE.FS` loads alone, and `sv_SE.address` then fails at first reach,
-naming `github.com/larvit/fejkdata/data/geo/SE`, which `sv_SE`'s manifest reads.
+naming `github.com/larvit/fejkdata/data/geo/SE`, which `sv_SE`'s manifest reads. `New`
+checks no `reads`: a stand-in providing the same paths under another name would fail it
+(goal 9.2).
 `--no-shipped-data -d` takes a locale's folder with its country's, or a set of one's own.
 
 ## The default embed holds every Swedish postort the import can place and give a street-delivery code and a street, and the US places of 25,000 or more