# AGENTS.md — internal/issue (DOMAIN)

**What an issue IS.** The canonical markdown format, the label taxonomy,
validation, checkboxes, the dependency graph, the store, and eviction.

It knows **nothing** about any tracker: no Gitea, no logins, no HTTP, no issue
numbers. Delete the transport entirely and this layer keeps working — issues that
live only on this machine are first-class, not drafts on their way somewhere.

Imports [`project`](../project/AGENTS.md) and the standard library, and nothing
else; two tests hold that, see [`internal/AGENTS.md`](../AGENTS.md).

| file | what is in it |
|---|---|
| `issue.go` | the `Issue` type, `FromText`/`Text`, `Slugify`, `IsSlug`, `UniqueID`, `DomainKeys` — and the package comment with the annotated file format |
| `meta.go` | `ParseMeta`/`RenderMeta`: the metadata block, one field per line |
| `taxonomy.go` | `Types`, `Severities`, the section headers, `RequiredSections`, `ExpectedSections`, `CanonicalLabels`, `SectionBody` |
| `template.go` | `Template`: the prefilled body per type |
| `validate.go` | `Validate`: errors mean malformed, warnings mean it deviates from its template |
| `checkbox.go` | `Checkboxes`, `SetCheckbox`, `CheckboxProgress` — pure functions over a string |
| `graph.go` | `Graph`, `Dependents`, `TopoOrder`, `FindCycles` over `depends:` |
| `depsection.go` | `BodyDepRefs`: references written in `## Depends on` / `## Issues` prose |
| `store.go` | `Root`, `AllIDs`, `SlugFiles`, `Load`/`LoadAll`/`Save`, `RequireStore`, `CreateStore`, `StoreError` |
| `index.go` | `BuildIndex`: INDEX.md, a view of the directory |
| `evict.go` | `Classify`, `Evict`, `Remove`, and the report types |
| `layering_test.go` | the two tests that keep a tracker out of this package |

## Identity

A slug derived from the title, and **the file name is the id**:

```
.kettle/issues/wire-sqlc-appclick.md
```

```
---
id: wire-sqlc-appclick
state: open
labels: [type/task, tech/sql]
assignees: [naudachu]
milestone: v0.2
depends: [migrate-schema]
origin: gitea
gitea: owner/repo#42
synced: 2026-08-07T18:40:00Z
---
# Wire sqlc into the appclick repo layer

## Summary
…
```

Keys down to `origin` are owned here. **Everything below is foreign**: written by
the sync layer, carried through load and save verbatim in `Issue.Extra`, never
read. That passthrough is what lets one file represent both a local issue and a
synced one without the domain learning a second vocabulary.

Every metadata field is one line and lists are inline, so plain grep works without
a parser:

```bash
grep -l  'labels:.*type/bug'          .kettle/issues/*.md
grep -ln 'depends:.*migrate-schema'   .kettle/issues/*.md   # who depends on it
```

`FromText` takes an id that **overrides** the one in the block, which is how the
store makes the file name authoritative.

## Origin is the safety argument

`origin: local` means **this file IS the issue** — there is no other copy, and
deleting it deletes the work. It is a complete state, not a pending one. Anything
with a tracker origin can be fetched again, which is what makes it safe to remove.

Every dangerous operation in this package turns on that one field:

- `Classify` splits the store into evictable, protected and still-open. It is
  **pure** — it reads loaded issues and decides, touching no disk — and a protected
  issue comes back as protected **even when it was named explicitly**: naming a
  file does not make deleting it safe.
- `Evict` classifies, removes, and rebuilds the index. One implementation, called
  both by the offline command and by the sync layer — which does nothing to this
  decision except hand over issues whose `state:` it has just refreshed.
- `Remove` is deliberately dumb: it takes an id, not a decision. Whether an issue
  may go is settled by `Classify` before this is reached, so the dangerous half of
  the operation has no branches in it at all.

The store is a **working set, not an archive**: a closed issue with a tracker origin
is evicted, and eviction is not a one-off migration — a pull by number fetches an
issue in any state, so a closed issue pulled after an eviction lands on disk again.

## The store, and the three ways it can be missing

`AllIDs` reads `<slug>.md` and nothing else. **A slug has no dot in it**, so
`wire-sqlc.comments.md` is not an issue; without that rule a bare push tries to
file a comment thread as a unit of work. `SlugFiles` is the same rule read the
other way round — everything named `<id>.<something>` belongs to that issue and
goes when it goes, which is how the domain removes an issue completely without
learning what a comment thread is.

Three failures, three messages, because they are three different things to do next:

| answer | means |
|---|---|
| `project.NotFoundError` | no project at all — run `kettle init` |
| `store … does not exist` | a project whose store was never created |
| `store … exists but is empty` | a store with nothing filed in it yet |

`ErrStoreMissing` marks the first two. Conflating "empty" with "not there" is
exactly what once made a missed directory look like an empty backlog. **Nothing
creates a store as a side effect of a write** — only `new` and `pull` call
`CreateStore`, and both announce it.

## Sections, and what a checkbox is

Section headers are fixed English literals in a fixed order; **only body prose is
Russian**. `RequiredSections` (`## Summary`, `## Spec`) must be present in every
type; `ExpectedSections` are the per-type ones and their absence is a warning.

`DepSections` — `## Depends on` and `## Issues` — both name what an issue depends
on, so both are edge sources pointing the same way. In a `type/feature` that reads
container → child: "the container is closed when its children are closed" *is* a
dependency, while "a child belongs to a feature" is membership, and membership has
no place in a dependency graph. Which is why a child never names its container back.

**`depends:` is the authoritative edge list; body prose is never walked by
`Graph`.** `BodyDepRefs` exists so a command can *report* what the prose claims,
and never so the graph can be built from it.

A checkbox is the one part of a body that is **state** and not prose. `SetCheckbox`
is surgical: exactly one byte of the input changes, and everything else — trailing
whitespace, the item's own wording, an existing `[X]`'s capital — comes back byte
for byte. Ticking a box must not produce a diff wider than the state that changed.
Fenced code blocks are skipped whole: `- [ ]` inside a fence is an example of the
markup, not a box anybody may tick.

`CheckboxProgress` is computed on the fly. Progress is not a metadata field — a
second copy of that state would be wrong by the next edit.

## Usage

```go
root := issue.Root(out)                 // out overrides; "" resolves the project
if err := issue.RequireStore(root); err != nil { return err }

issues, err := issue.LoadAll(root)
order := issue.TopoOrder(ids, issue.Graph(issues))   // dependencies first
errs, warns := issue.Validate(issues[id], knownIDs)
```

`TopoOrder` breaks cycles deterministically rather than raising: a cycle is a data
problem for the caller to report (`FindCycles` finds them), not a reason to refuse
to order the rest.

## What does not belong here

An issue number, a login, an HTTP call, a label colour, a hex code, a JSON tag, a
yaml tag. If one appears in this package it is in the wrong place — colours are
[`mapping`](../mapping/AGENTS.md)'s, because a hex code is how a tracker paints a
chip and not what an issue is.

## Keeping this file true

- **Scope:** every `.go` file in this directory — the format, the taxonomy, the
  store, the graph, checkboxes, eviction.
- **Update it when** a metadata field is added to `DomainKeys`, a type or severity
  is added to the taxonomy, a required or expected section changes, a file appears
  or goes in the table above, or any rule about what may be deleted changes. The
  format's operator-facing statement of intent is embedded in the binary
  (`cli/internal/scaffold/assets/skills/kettle-issue/references/format.md`) — when
  the taxonomy moves, both change.
- **Do not** document how any of this reaches a tracker.