diff --git a/CLAUDE.md b/CLAUDE.md index 6e937d8..b625fbb 100644 --- a/CLAUDE.md +++ b/CLAUDE.md @@ -25,7 +25,7 @@ The README is a 50,000-foot view — what markfluence does, which command to rea **`docs/commands/` is generated, not written.** `tools/gendocs` renders every command's help to markdown via cobra's doc generator (using `cmd.Root()`, exported for that one caller — a `main()` inside `cmd` would land in the binary, and a `_test.go` that writes into the repo is not a test). It is a second copy of the help text, and only safe because it cannot drift: `make docs-check` regenerates into a temp dir and diffs, inside `make check`. `DisableAutoGenTag` is set, or a timestamp would make every regeneration a diff and the guard noise. **Never hand-edit a file under `docs/commands/`.** -The rest of `docs/` is written: `markdown_file.md` (the page format — every frontmatter field and every body construct, the two halves that used to be split between the README and a separate file), `json-output.md` (per-command `--json` detail the schema cannot express as reasoning), `github-actions.md` (CI setup), `root-model.md`, `guarantees.md`, and `confluence/`. +The rest of `docs/` is written: `markdown_file.md` (the page format — every frontmatter field and every body construct, the two halves that used to be split between the README and a separate file), `json-output.md` (per-command `--json` detail the schema cannot express as reasoning), `github-actions.md` (CI setup), `root-model.md` (the documentation root *and* `markfluence.yaml`'s settings), `guarantees.md`, and `confluence/`. A change that adds a package, exports a function, adds a make target, or introduces a generated artifact belongs in **this file** as part of the same change. The only time it has drifted was a docs-only branch that felt like it needed no architecture note while adding all four. @@ -70,6 +70,7 @@ Module `github.com/mozilla/markfluence` (`go 1.25`). `main.go` is a shim to `cmd - `cmd/attachment{list,upload,download}/` — the flat `attachment-list`/`attachment-upload`/`attachment-download` commands (noun-first so cobra's alphabetized help keeps them together and `attachment-` completes as a group). `upload` reuses the checksum skip/update logic, with `--force` (`client.ForceUploadAttachments`) and `--dry-run` (`PlanAttachments`); its `--name` takes a *path* whose base name becomes the stored name, and the recorded `path=` is the path as given, so a later publish can't create a duplicate under a different name; a batch whose base names collide is refused, since `planAttachments` reads the page's attachments once before its loop and would otherwise plan two creates for one name. `download` restores an attachment to its recorded `path=`, using the stored name verbatim when there is none (never interpreting it — a file really called `a%2Fb.png` must not be scattered into `a/b.png`, and `convert.sourceFor` answers the same way on the markdown side, which is what keeps a downloaded file where the markdown says it is), with `--flat` to opt out; `destPath` is the only place server data becomes a filesystem path and clamps to `--dest`, refusing rather than clipping an escape, since `..` is legitimate in a source path. - `cmd/schema/` — `schema`: print the embedded `--json` schema to stdout verbatim (no args, no credentials, no Confluence call). `--json` is deliberately a no-op — the output is already the schema document, not an envelope — which is also why `schema` is absent from the schema's own `command` enum. - `schema/` — the published JSON Schema (`json-output/v1.json`) *and* the `schema` Go package that embeds it (`V1`). The Go file lives beside the schema because `go:embed` cannot reach outside its own directory, and the schema stays at a top-level path a non-Go consumer can browse, mirroring its own `$id`. `internal/schematest` validates against the embed rather than reading the file, which is what makes "what ships" and "what the tests checked" the same bytes — do not reintroduce a disk read or a second copy. The version number is **not** restated here: `jsonout.SchemaVersion` and the document's own `schema_version` const are the two copies, tied together by a test in `cmd/schema`. The envelope's and the error object's top-level **`warnings`** are the one field no command fills: `jsonout.NewEnvelope`/`EmitError` drain a package-level collector (`AddWarning`), because the only thing in it is raised during credential resolution — below any command, before either document exists. +- `internal/project` — the documentation root: `Discover` (walk up from a directory looking for `markfluence.yaml`), `FromPath` (`--root`), `Resolve`, and `Cache`, which consults itself at every level of the walk so a batch spanning a subtree pays for the walk — and `os.OpenRoot` — once rather than per directory (the quadratic cost `_plans/025` measured). A `Root` carries `Dir`, `File`, `Config` and an `os.Root` that refuses an escape even through a symlink partway down. `Discover` is called from **two starting points for two reasons** — once per invocation from the working directory to locate `.env`, and once per markdown file from its own directory to bound its reads and name its attachments — which is why it returns a type rather than a string; the two diverge legitimately, so a multi-root batch is allowed and nothing refuses it ([docs/root-model.md](docs/root-model.md)). `config.go` reads the project file's **settings** (#100): `space` and `page_width`, resolving **flag > frontmatter > project file**, which is *not* the credentials chain and must never be conflated with it. Three things about it are load-bearing. It is read through `frontmatter.Dialect.ReadMapping` rather than a second parser, since every rule there was found by probing goccy and a second copy would be a second set of the same bugs. An **unknown top-level key is fatal**, and that is the point rather than a cost — a silently ignored `spce: ENG` is wrong for every file at once, and a file written for a newer markfluence holds keys this binary would ignore, so there is no schema version and this must not be loosened; an empty or comment-only file stays valid, being what ships and what `export` plants. And loading happens in `open()`, the single place a `Root` is built from a marker hit, so `Discover`/`Cache`/`FromPath` cannot disagree that a file which cannot be understood **is not a valid marker**: the walk does not continue upward and does not fall back to the starting directory, because the root decides every attachment name and guessing at it is worse than stopping. `ConfigError`/`IsConfigError`/`RootError` exist so a caller reports that as a local defect (`VALIDATION`) rather than under `resolving the documentation root` as I/O. What it validates is **structure only**: `internal/pagewidth` cannot be imported here (`pagewidth` → `client` → `project`), so a width's vocabulary is checked by `pagewidth.Declared` where it already runs and by `check`'s offline lint. `Config` deliberately holds **no `url` or token**, and the reason is sharper than "those are credentials": basic auth goes to whatever host the resolved URL names, so a committed, walked-up file naming one would decide where `CONFLUENCE_TOKEN` is sent — a worse version of the `.env` hole #136 records. - `internal/pageslug` — `Slug`/`For`/`Filename`: a title to a filename-safe slug. A package rather than a helper because `export`, `read` and `attachment-download` all place attachments under a page's own directory and must agree. It lowercases (so case-variant titles collide and can be caught) and drops `/` (so no title can inject a path separator); it is lossy, and no readable slug can avoid being, so the caller decides what a collision means. Known limit: NFD and NFC spellings of one title are different Go strings but one filename on APFS, so that pair is not disambiguated. - `internal/pagedoc` — a fetched page as a markdown document: `Render` (frontmatter + converted body), `Frontmatter`, and the lookups the converter can't do for itself — `Sources`/`SourcesFrom` (attachment name → recorded source path) and `PageLinks` (the page an `` points at → its URL). **One conversion, parameterized by a `Placement`**: where the page's file sits, where its unrecorded attachments go, what `parent:` says, and the attachment listing the caller already has. `read`, `export` and `attachment-download` all go through `Options`/`AttachmentDirFor` rather than assembling their own, so they cannot drift by accident — only by argument. For a page at the top level of what is being written, which is what `read` prints and what a single-page export writes, `read` and `export` are byte-identical; deeper in a tree they differ in exactly the position-dependent parts (a sourced attachment's `../` prefix, a `-` suffix a sibling forced, and `parent:`), because `read` has no tree to be positioned in. It needs a client (page width, attachment list, title lookups), which is why it isn't in `internal/convert` — that package is deliberately client-free, and it's why `StorageToMarkdown` takes those maps rather than fetching them. Every one of them is best-effort in the same shape: no references in the body means no request at all, and a lookup that fails is omitted rather than fatal (an omitted page link renders as raw storage, not as a link with no destination). It also owns **`UserCache`**, the user-name lookup both mention directions share (#91): a per-run, **cross-page** cache, threaded in from the caller the way `project.Cache`/`linkindex.Cache` are, because the obvious structure is wrong — `PageLinks` builds its space-id map per page and `Options` is built per page, so a user map written that way would re-resolve the same twelve people on every page of a 200-page export. It **remembers misses**, or a page mentioning deactivated people costs a request each, every page, to learn the same failures. Not persisted to disk, and the reason is **L2**: output must depend only on the files on disk, not on what a cache happens to hold. `MentionWarnings` is the forward direction's use of it, and sharing the cache is what makes that warning affordable — publishing needs no display names at all, so that lookup exists purely to report an id that names nobody. `PageLinks` resolves a space id **once per space key**, not once per link, and refuses to search site-wide when it can't scope a title to a space — a same-titled page in the wrong space is a wrong answer, which is worse than the passthrough a miss produces. - `internal/attachfile` — `Resolve` (where an attachment goes under a destination root, **including the traversal clamp**) and `Write` (download it there, honoring force/dry-run). Shared by `attachment-download` and `export`; the clamp must never exist in two copies. @@ -77,7 +78,7 @@ Module `github.com/mozilla/markfluence` (`go 1.25`). `main.go` is a shim to `cmd - `internal/pageref` — `Resolve`, the single page-argument resolver: a numeric id, a Confluence page **or folder** URL (`pagePathRE` matches both `/pages/` and `/folder/`, since `children` takes a folder and a folder URL is what a browser hands you — the id is all it returns, so a command that can only use a page reports its own not-found), or a `.md` file whose frontmatter has a `page_id` (stat'd first, so `123.md` is a file). Every command taking a page uses it. `message.go` also owns the wording for the two ways a *frontmatter* `page_id` is wrong — `NotFoundMessage` (caller supplies the remedy, which differs per command) and `NotNumericMessage` — because `create`, `update`, and `fix` all report them and a reader should recognize the same problem across all three. They return strings, not errors: `create` wraps the text in its typed `pageIDFailure` (which also carries the `--json` fields), the others want a plain error. Anything checking a `page_id` before a request uses `IsDigits`, since the API answers a non-numeric id with a 400 whose body says nothing useful. - `internal/client` — `ConfluenceClient` over `net/http` with basic auth. Built from a `Config` (site URL, cloud ID, username, token) via `New`; it carries **two bases**: `BaseURL()` is where requests go (the gateway when a cloud ID is set) and `SiteURL()` is always the site. Anything a reader sees uses `SiteURL()` — printed page URLs and, critically, the `baseURL` handed to `convert.MdToConfluence`, since rewritten links are published *into* the page. Pages are Confluence **v2**; attachment writes and the user lookup are **v1** (`/wiki/rest/api/...`). A **folder** — the Cloud content type that can parent a page — has its own v2 route, `GetFolderOrNil` against `/wiki/api/v2/folders/{id}`, because every v2 *page* route answers a folder id with 404; enumerating children, if it is ever added, must be v1, since v2 cannot list inside a folder at all and its page-children route silently omits folders ([docs/confluence/folders.md](docs/confluence/folders.md)). Typed `HTTPError`, per-attempt context timeouts, centralized retry/backoff in `send`. `HTTPError.Error()` appends a **hint** for the three auth failures whose status misleads, matched on the response *body* rather than deduced from the status and always **appended** to it, never replacing it. The one that matters: **a rejected credential is a 404 on every v2 route**, so a revoked token used to make `read` answer `page ... not found` about a page that exists. `RejectedCredential` tells it apart by the fact that every genuine v2 404 *names* what it could not find and the auth one does not, `notFound` gates the three `…OrNil` helpers on it so they stop reading it as "absent", and `jsonout.CodeFor` checks it before the status switch so `--json` reports `AUTH` rather than `NOT_FOUND`. **Two error types on the request path, and one predicate for them**: an `*HTTPError` once a response has a status, an unexported `requestError` when there is none (a transport failure, a request that would not build, a body that would not decode), and `FromRequest` answers whether an error is either. That is what lets a caller tell a server failure from a local one — `jsonout.CodeOr(err, fallback)` is the whole point of it, since `CodeFor` alone reports every non-`HTTPError` as `NETWORK` and so turns `no title given` into a network problem (#133). The rule is deliberately scoped to the request: `DownloadAttachment` writing to the caller's writer, `uploadAttachment` opening the caller's file, and `Resolve` reading the environment stay untyped, because tagging them would misreport an unreadable file as a network failure. The wrapper carries no message of its own, so `Error()` is the inner text verbatim and nothing a reader sees changed. A 403 that is not one of the two measured credential phrasings gets no hint, because that is what a genuine permission denial looks like ([docs/confluence/api.md](docs/confluence/api.md#scopes)). **Retry rules**: 429 for any method; 502/503/504 for idempotent methods; **any other 5xx only when the response carries `Retry-After`** — that is how a 500 becomes retryable, and it is why `parseRetryAfter` reports the header's *presence* apart from its delay (`Retry-After: 0` means "retry now", not "no header"). The exponential delay is jittered, a server-supplied `Retry-After` never is. Decisions go to a package-level hook (`SetRetryLogger`, set once in `root.go` beside `ui.SetDebug`) and fire whichever way they went, because `internal/client` prints nothing and a silent twelve-minute retry storm is otherwise indistinguishable from a hang. **A versioned PUT is not as idempotent as its method**: `SetContentProperty` retry-once on top (recovers a lost create-POST response) and `UpdatePage`'s `updateLanded` both exist for the same reason — a write whose response was lost gets re-sent, and the re-sent version is refused. `updateLanded` requires version *and* title *and* body to match what was sent, since a concurrent edit could have produced the version alone and claiming success over someone else's content is worse than a false failure ([docs/confluence/api.md](docs/confluence/api.md)). `SyncAttachments` (skip/update by a SHA-256 recorded in the attachment's comment, alongside the source path so `read` recovers image paths exactly; only the current comment form is parsed — an attachment stamped by a markfluence predating a comment-format change reads as unmanaged and is re-uploaded once, the same as any hand-uploaded file — except that a *recorded path disagreeing with the local source* is an update even when the checksum matches, so a mangled path repairs itself instead of surviving every later publish; a comment with no source recorded at all is not a disagreement. Every text part of the upload form must go through `writeTextField`, never `multipart.Writer.WriteField`, which emits no charset and gets decoded as Latin-1), `_links.next` pagination. **Three pagination schemes, and picking the wrong one truncates silently.** v1 *child/attachment* collections page through the generic `listV1` helper by `start`/`limit` offset, never `_links.next` (absent when the results fit one page, so it cannot terminate a loop); `ListAttachments`, `ListChildPages`, and `ListChildFolders` all go through it. v2 collections page through `listV2` by the cursor in `_links.next`, which is a `/wiki`-prefixed absolute path `resolveNext` handles unchanged; `ListContentProperties` and `SearchPagesByTitle` share it. **`/wiki/rest/api/search` is neither**: it ignores `start` outright, its `next` is context-relative so it needs the `/wiki` prefix `resolveNext` does not add, a short page does *not* mean the end, and `totalSize` can be nonzero against an empty `results` — so `searchCQL` terminates only on a missing `next` and nothing may branch on `totalSize` ([docs/confluence/search.md](docs/confluence/search.md)). `searchCQLBounded` adds a row bound under it (`SearchCQL` is that call with no bound, which is why `find` is unaffected): it asks for `max+1` and reports the surplus as `more`, since `totalSize` cannot supply a count. Full text goes through `SearchText`/`SearchRawCQL`, which return the cleaned `SearchMatch` the way `FindByTitle` returns `TitleMatch` — and **every field of a match comes from the row's `content` object**, because the row-level `title` is HTML-escaped *and* wrapped in `@@@hl@@@` markers where `content.title` is neither. The `excerpt` exists only at row level, so `cleanExcerpt` strips those markers, unescapes once, and collapses to one line — in the client, so the human and `--json` paths cannot disagree about it. `excerpt=highlight` is passed explicitly and **re-attached when following the cursor** (the `next` link carries `cql` and `limit` but not `excerpt`, and `doJSON` appends params with a bare `?`); an unrecognized value there yields an empty excerpt with a 200, so a rename by Atlassian degrades to no excerpts rather than an error. A row with no `content` object is skipped and **counted** — `type = space` answers with hundreds of them, and a silent skip would report a successful empty result. A bare v1 child row already carries `webui`, `status`, and `extensions.position`, so child listing needs no `expand`. `DownloadAttachment` goes through `send` (inheriting retry/backoff) against `_links.download`; **never** add a `CheckRedirect` that forwards headers — it would leak site credentials to Atlassian's media host, which neither needs nor wants them. `config.go` holds `Resolve` and the `.env` reader, plus the **`.env` permission warning** (#136): a `.env` reachable by anyone but its owner (`mode.Perm()&0o077`) *and* containing `CONFLUENCE_TOKEN` earns a warning naming the file, its mode, and the `chmod`. Both halves matter — a `.env` holding only the URL and username leaks nothing, and a warning that fires on a file with no secret in it is how one becomes something people scroll past. It stats rather than lstats (a link's own `0777` would cry wolf over a `0600` target), lives in `loadDotenv` because that is the one function both the discovered `.env` and `--env-file` pass through, and reaches the reader through `SetSecurityWarner` for the same reason `SetRetryLogger` exists — wired to `cmd/root.go`'s `reportSecurityWarning`, which prints it (human mode) *and* records it via `jsonout.AddWarning`, since stderr under `--json` is a schema-validated document with no room for a stray line. A group/world-*writable* `.env` with no token in it is knowingly **not** covered, though `CONFLUENCE_URL` resolves from there too and rewriting it would redirect the token: see #136. Why each of these is shaped this way, with the evidence: [docs/confluence/api.md](docs/confluence/api.md) and [attachments.md](docs/confluence/attachments.md). - `internal/convert` — the converter (the crux). `MdToConfluence(md *frontmatter.MarkdownFile, root *project.Root, index *linkindex.Index, baseURL, spaceKey, version string) (*ConfluencePage, error)`. `root` bounds which images and parent references may be read (S1/S2) and is what an image's recorded `Source` is relative to; `index` is the tree-wide link/anchor index for `root` (`internal/linkindex.Build`), built once and shared across every file converted under it rather than rebuilt per conversion — both are discovered/built by the caller (`internal/project`/`internal/linkindex`), which is why this package stays client-free. It parses with goldmark (GFM) and renders through a custom `storageRenderer` registered at priority 100 (below the default HTML=1000 and table=500 renderers) that emits Confluence storage format. `shield.go` renames raw `ac:`/`ri:` tags to colon-free sentinels around the goldmark step so pasted storage passes through; `callouts.go` is an AST transformer + blockquote renderer for GitHub alerts; `mention.go` owns the user-mention mapping in both directions (#91): a mention is 80% of all `` usage, and it converts to `[@Display Name](https://home.atlassian.com/people/{accountId})`. Three things decide its shape, each measured rather than reasoned. **The URL is Atlassian Home, not the site** — Confluence's own renderer still emits `{site}/wiki/people/{id}`, which no longer resolves usefully in a browser, so a mention in markdown names *no site*, needs nothing from configuration, and is therefore recognisable by `check` with no client at all. **Matching is on the path, ignoring host and query**, because several spellings of one target circulate (the Home URL, the modal's `?cloudId=` copy, the `/o/{orgId}` redirect, both Confluence forms, root-relative) and none of `cloudId`/`ref`/the org segment identifies the person — only the id does, and `ri:user` stores nothing else. **The `@` on the link text is the marker**, load-bearing rather than decoration: the URL cannot tell "mention this person" from "link to their profile", so without it anyone writing the second would silently get the first. The account id is **not** pattern-validated (two shapes are live on one instance, so a pattern tight enough for one rejects the other) and `ri:local-id` is never emitted (a mention carrying only the id resolves to the same person, verified via ADF). `ConfluencePage.Mentions` reports the ids the *forward* direction emitted so the caller can warn about one that names nobody — the `Attachments` arrangement, and necessary because Confluence accepts any id and renders `@Unlicensed user` rather than failing, and the profile URL 200s either way. An unresolvable mention still renders as a link, `[@Unlicensed user](…)` — that wording mirrors Confluence because the only ids reaching it are the ones the page labels that way: a **deactivated account resolves normally** and keeps its name (measured across every mention on a real page — 18 of them, six departed, all 200, returning e.g. `Mark Reid (Deactivated)`), so a departed colleague never takes that branch. Name resolution is `pagedoc.UserCache`, a per-run cross-page cache, and the tri-state is the part to preserve: `client.LookupUser` separates a name from `ErrNoSuchUser` from an unaskable question, `StorageOptions.UserNames` carries that as name / `""` / absent, and only a **confirmed** absence renders the placeholder. Flattening those would write a fabricated name over a real one the moment a VPN dropped mid-export, across a whole tree, into a file that then looks authoritative — which is also why the cache remembers a 404 but not a timeout (one is an answer, the other is not) and why `MentionWarnings` warns only about a confirmed absence; `aclink.go` is the *inverse* direction's one element with enough shape to need its own file — ``, which the editor writes for every internal link and `MdToConfluence` never emits, so nothing in the regression suite covers it. One rule decides its whole mapping: **convert when the markdown republishes to a link resolving to the same target, pass the storage through when it would not** — so a page link and a space link convert, while a mention and a space link convert, and an attachment link (only images are uploaded, so a relative href would be dead) and an unresolvable target stay raw, which the shield republishes byte-identical. A page target is a **title, never an id**, so `PageLinkTargets` reports what needs resolving and `StorageOptions.PageLinks` carries the answers back. An `ac:anchor` is **percent-encoded** where `confluenceSlug` output is not: decode it before matching a heading, leave it encoded inside a URL. A same-page anchor recovers its heading from the document rather than inverting the slug, which is impossible — `confluenceSlug` turns both a space and a hyphen into `-`. The survey the mapping rests on, and the `xml.HTMLAutoClose` trap that made `` crash the parser outright (#88), are in [docs/confluence/links-and-anchors.md](docs/confluence/links-and-anchors.md); Plain text used as a markdown link's text goes through `escapeLinkText` (`\`, `[`, `]`), applied to the *raw* sources only — a page title, a space key, an anchor, a display name — and via `inlineTextForLink` to a body whose every descendant is a text node. Never to already-rendered output: an `ac:link-body` holding markup has been converted to markdown already, and escaping it yields a literal `\*\*bold\*\*`. Both directions are tested, because a fix at either extreme passes one and fails the other. `attachname.go` owns the source-path→attachment-name mapping, which is now the path's **base name** and nothing else (#59/`_plans/029`): the name is the attachment's identity, so an encoded path moved the name every time the file moved and orphaned the old attachment, and the path is recorded in the comment anyway. The mapping is therefore lossy, and what the bijection used to buy is an explicit refusal — two assets in one document whose base names agree return a typed `NameCollisionError` from `MdToConfluence`, which is a *failure* and not a `Broken` entry, since nothing blocks a publish on `Broken`. `check` catches that error and reports it as `Broken` anyway, because there it is a document defect like a dead link rather than a converter failure. A stored name is never interpreted in the other direction either: `sourceFor` reads the recorded path or uses the name verbatim. What names Confluence accepts is in [docs/confluence/attachments.md](docs/confluence/attachments.md); `destination.go` owns the **other** codec, destination↔path (`decodeDestination`/`encodeDestination`), shared by images *and* doc links — a markdown destination is a URL, so decode inbound (**before** `withinRoot`, or an encoded `..%2F` slips the clamp) and encode outbound in `storage_to_md.go` (or `export` emits markdown that no longer parses, and `sourceFor`'s absolute-path refusal is undone by the next read); an undecodable destination is a literal `%` in a filename, not an error; the reasoning is in [docs/confluence/links-and-anchors.md](docs/confluence/links-and-anchors.md); `images.go` (resolution stays page-relative like GitHub; the documentation root — cwd — bounds what may be published, and an image above it is `IMAGE BROKEN`), `links.go` (GitHub/Confluence slugs, doc-link + anchor rewriting against `internal/linkindex`'s tree-wide index; `resolveDocKey` resolves a destination to the index's root-relative key and reports `escapes` — a purely lexical check on the *query* side, since the index itself needs no clamp: an escaping key can never be in it, built by walking downward from root). A doc-link target is one of four severities, #42: missing entirely or escaping root is **Broken** (`LINK BROKEN: … (not found|outside the documentation root)`) and replaces the whole `` element — tags and visible text alike — with that literal message, matching `images.go`'s precedent for a missing image (`renderLink` needs a small per-node flag, `linkBrokenText`, since goldmark still invokes a container node's renderer on the matching leaving call regardless of `WalkSkipChildren` on entering, and there is no `` to write in the broken case); existing on disk with no `page_id` yet is unchanged — a **warning**, the normal state of an unpublished tree; a `#fragment` matching no heading on an otherwise-resolving target also **warns**, gated on `linkindex.Index.FileExists` so a missing/escaping target isn't double-reported. `tables.go` (the `` tag, stamped with `data-layout="align-start"` so tables auto-size and left-align — this must stay if column widths are ever emitted, or a `` silently induces a layout; plus cells: an AST transformer consumes a leading `` comment in a cell and `renderTableCell` emits it as `data-highlight-colour`; `storage_to_md.go`'s `cellTexts` reverses this, reading `data-highlight-colour` back into a `bg:` marker (`cellBGNames`, the reverse of `tables.go`'s swatch map — a hex outside the 21 swatches round-trips as the literal hex, and where two names share a hex the British spelling wins, matching Confluence's own `-colour`), and a column's GFM alignment becomes a `

` wrapper **inside** the cell — never the `align` attribute the GFM renderer would emit, which is the one form Confluence discards. Only center and right are emitted: Confluence has no explicit left, so `:---` publishes bare and `read` recovers it as `---`. Since alignment is per-paragraph there and per-column in GFM, `columnSeparators` in `storage_to_md.go` takes each column's most common declared alignment (ties to the first seen) and drops the rest. Rows still fall through to the GFM renderer. A multi-line cell is one `

` per line — Enter in the editor starts a new `

`, it does not insert a `
` — so `renderCellLines` in `storage_to_md.go` joins sibling `

` children with a literal `
` rather than nothing: a GFM table row is exactly one physical line, so a real newline isn't an option, and the same substitution catches a bare mid-line `
` (Shift+Enter) that would otherwise render as the two-space hard break valid in ordinary block content but not inside a table row. A `