lift limit on cid

src/domain.rs

@@ -0,0 +1,549 @@
+//! `contentKind` → `domain` / `workForm` — the routing tables from
+//! METADATA_KEYS.md §1.
+//!
+//! `domain` answers **"which application is this record destined for?"**. It
+//! is the coarsest facet in the registry and the key every client filters its
+//! catalogue on — **one value per app**, no alternation:
+//!
+//! ```text
+//! meta-watch   →  domain:screen
+//! meta-listen  →  domain:music
+//! meta-read    →  domain:literature
+//! ```
+//!
+//! `workForm` answers the *other* question the old `film`/`tv` split was
+//! secretly encoding: **is this work complete in itself, or one instalment of
+//! a run?** (`standalone` | `serial`). It is cross-domain — a comic issue is
+//! `serial` in `literature` exactly as an episode is `serial` in `screen` —
+//! which is what lets a client ask for it independently of the wall.
+//!
+//! # Why they are stored and not derived on read
+//!
+//! `contentKind`'s vocabulary is deliberately open — a new feeder may mint a
+//! kind and ship without a fleet-wide update. That only stays safe because the
+//! domain travels *with* the record: a peer that has never heard of
+//! `podcastEpisode` still routes it correctly, because it never has to
+//! interpret the token. Deriving on read would silently drop every record
+//! whose kind the reader predates. The same argument applies to `workForm`,
+//! plus a second one: the two kinds that most need it (`pack` and `card`) are
+//! exactly the two the kind alone cannot decide.
+//!
+//! # ⚠ The binding is permanent and one-way
+//!
+//! Add kinds freely; **never re-map an existing kind to a different domain**.
+//! Because the value is stored, two peers on different versions that disagree
+//! about where `audiobook` belongs produce a split-brain that redeploying
+//! cannot heal — the wrong domain is already written into records across the
+//! mesh. If a kind genuinely has to move, mint a new kind.
+//!
+//! The `film`+`tv` → `screen` merge (METADATA_KEYS.md §14.17) is the one
+//! deliberate exception, taken once and early and paid for with a one-shot
+//! meta-core corpus sweep. It is not a precedent.
+//!
+//! # Why `domain` and not one kind-key per medium
+//!
+//! `record_matches` is AND-across-keys / OR-within-key, and a non-matching key
+//! fails the record outright. A per-medium split (`videoKind` / `audioKind` /
+//! `documentKind`) would force meta-listen to express "music video **or**
+//! audio track" as an OR across two *different* keys — which the query
+//! language cannot represent at all. One domain key, OR-ed within itself,
+//! always can. `workForm` is one key everywhere for the same reason.
+
+/// The `contentKind` → `domain` table. A kind absent from this list has no
+/// domain and is **not independently routable** — correct for sidecars
+/// (subtitles, artwork) and for un-anchored hits, a producer bug for anything
+/// else.
+///
+/// ⚠ `pack` is deliberately absent. A season pack and an album release are the
+/// same structural thing, so the kind alone cannot tell `screen` from `music`;
+/// the writer stamps `pack`'s domain from its own context (the same reason
+/// `derive_file_type` cannot have a second `pack` arm).
+///
+/// ⚠ `podcast` / `podcastEpisode` are absent too: the `spoken` domain was
+/// retired unused (METADATA_KEYS.md §14.17), and the PR that first *writes*
+/// those kinds picks their domain.
+const DOMAIN_BY_CONTENT_KIND: &[(&str, &str)] = &[
+    // screen — everything meta-watch consumes, films and serials alike. The
+    // standalone/serial split lives in `workForm`, not here.
+    ("movie", "screen"),
+    ("series", "screen"),
+    ("episode", "screen"),
+    // music
+    ("track", "music"),
+    ("album", "music"),
+    ("artist", "music"),
+    ("musicVideo", "music"),
+    ("djMix", "music"),
+    ("liveSet", "music"),
+    // literature — an audiobook's identity is the book (same author, same ISBN
+    // family, same series as the ebook), so meta-read groups the two editions
+    // on one page. The player does not decide the domain.
+    ("book", "literature"),
+    ("audiobook", "literature"),
+    ("comic", "literature"),
+    ("manga", "literature"),
+    ("magazine", "literature"),
+    // science
+    ("paper", "science"),
+];
+
+/// The `contentKind` → `workForm` table (METADATA_KEYS.md §1).
+///
+/// `standalone` = a work complete in itself. `serial` = an instalment of an
+/// ongoing run, **or the container or headline for one** — which is why a
+/// `series` card and an `episode` are both `serial`.
+///
+/// ⚠ `pack` is absent for the same reason it is absent above: a season pack is
+/// `serial`, an album release is `standalone`, and only the writer knows which.
+const WORK_FORM_BY_CONTENT_KIND: &[(&str, &str)] = &[
+    // screen
+    ("movie", "standalone"),
+    ("series", "serial"),
+    ("episode", "serial"),
+    // music — an album is a closed work, not an ongoing run, so every rung of
+    // the music ladder is standalone.
+    ("track", "standalone"),
+    ("album", "standalone"),
+    ("artist", "standalone"),
+    ("musicVideo", "standalone"),
+    ("djMix", "standalone"),
+    ("liveSet", "standalone"),
+    // literature — the split that proves `workForm` is not a screen-only axis.
+    ("book", "standalone"),
+    ("audiobook", "standalone"),
+    ("comic", "serial"),
+    ("manga", "serial"),
+    ("magazine", "serial"),
+    // science
+    ("paper", "standalone"),
+];
+
+/// Resolve the domain a `contentKind` belongs to.
+///
+/// Returns `None` for `pack` (not derivable from the kind — the writer supplies
+/// it), for format/sidecar kinds that route nowhere, and for any kind this
+/// build has never heard of. A caller that already knows the domain from its
+/// own context must prefer that over this table.
+pub fn domain_for_content_kind(content_kind: &str) -> Option<&'static str> {
+    lookup(DOMAIN_BY_CONTENT_KIND, content_kind)
+}
+
+/// Resolve the work form a `contentKind` sits on. Same contract as
+/// [`domain_for_content_kind`]: `None` means "not derivable", never a guess.
+pub fn work_form_for_content_kind(content_kind: &str) -> Option<&'static str> {
+    lookup(WORK_FORM_BY_CONTENT_KIND, content_kind)
+}
+
+fn lookup(table: &'static [(&'static str, &'static str)], key: &str) -> Option<&'static str> {
+    let k = key.trim();
+    table
+        .iter()
+        .find(|(kind, _)| kind.eq_ignore_ascii_case(k))
+        .map(|(_, value)| *value)
+}
+
+/// Kinds whose `domain` the kind→domain table deliberately cannot decide, so
+/// the **writer** supplies it (METADATA_KEYS.md §1). Today that is `pack`
+/// alone: a season pack and an album release are the same structural thing, and
+/// only the producer knows which — indexer-feeder's `bt.rs` reads the domain off
+/// the per-file kind *before* overwriting it with `pack` precisely so the value
+/// survives.
+///
+/// They must ride along in every `domain:` → `contentKind:` expansion. The
+/// expansion is only ever a **pre-filter** — the real `domain:` term is enforced
+/// afterwards by [`crate::query_eval::record_matches`] — so widening it is free,
+/// while omitting these kinds would drop exactly the records whose `domain` is
+/// the most authoritative one on the wire.
+pub const WRITER_SUPPLIED_DOMAIN_KINDS: &[&str] = &["pack"];
+
+/// The `workForm` twin of [`WRITER_SUPPLIED_DOMAIN_KINDS`], and for the same
+/// reason: a season pack is `serial`, an album release is `standalone`.
+pub const WRITER_SUPPLIED_WORK_FORM_KINDS: &[&str] = &["pack"];
+
+/// The inverse: every `contentKind` that belongs to `domain`.
+///
+/// Used at the gateway-routing boundary. A gateway declares the *content kinds*
+/// it serves (`served_content_kinds`), not domains, so a `domain:` filter is
+/// matched by expanding it here rather than by adding a `served_domains` field
+/// to the heartbeat — which would be a wire-protocol change requiring every
+/// feeder manifest and every peer to move at once.
+///
+/// ⚠ Since the `film`+`tv` merge this returns **several** kinds for `screen`
+/// (`movie`, `series`, `episode`) where the two old values were disjoint. A
+/// caller that reads only the first element silently means "movie" — scan the
+/// whole list, or narrow with a `workForm:` term first.
+pub fn content_kinds_for_domain(domain: &str) -> Vec<&'static str> {
+    inverse(DOMAIN_BY_CONTENT_KIND, domain)
+}
+
+/// The inverse of the `workForm` table. Same routing-boundary role, same
+/// scan-the-whole-list warning as [`content_kinds_for_domain`].
+pub fn content_kinds_for_work_form(work_form: &str) -> Vec<&'static str> {
+    inverse(WORK_FORM_BY_CONTENT_KIND, work_form)
+}
+
+fn inverse(table: &'static [(&'static str, &'static str)], value: &str) -> Vec<&'static str> {
+    let v = value.trim();
+    table
+        .iter()
+        .filter(|(_, val)| val.eq_ignore_ascii_case(v))
+        .map(|(kind, _)| *kind)
+        .collect()
+}
+
+/// Rewrite a query so a `domain:` / `workForm:` filter can reach a plugin that
+/// has never heard of either key.
+///
+/// Returns `None` when the query carries neither — the common path, and cheaper
+/// than cloning.
+///
+/// # Why translate instead of teaching every plugin
+///
+/// `record_matches` fails a record outright when a filter key is missing from
+/// its fields, and `domain` is missing from every record a not-yet-updated
+/// feeder emits (`workForm` from every record written before it existed).
+/// Most feeders pin the SDK by git tag, so they cannot pick up a new key on our
+/// schedule. Translating `domain:literature` into the `contentKind:`
+/// alternation it covers means the wire query a plugin sees never mentions
+/// either key — old plugins keep working unchanged, while the dispatcher still
+/// enforces the real filters afterwards, against records it has just stamped.
+///
+/// # The two axes intersect
+///
+/// `domain:screen workForm:serial` covers `series` and `episode` — the
+/// **intersection**, not the union. Widening to the union would hand a serial
+/// query the whole film corpus as a pre-filter; the post-stamp check would then
+/// throw it away, having already paid for it upstream.
+///
+/// An explicit `contentKind:` filter already in the query is left alone: it is
+/// the narrower of the three, and the `domain`/`workForm` terms are still
+/// enforced post-stamp, so the AND semantics hold either way.
+pub fn expand_routing_filters(
+    query: &crate::query::GatewayQuery,
+) -> Option<crate::query::GatewayQuery> {
+    let domains = query.filters.get("domain");
+    let work_forms = query.filters.get("workForm");
+    if domains.is_none() && work_forms.is_none() {
+        return None;
+    }
+
+    let by_domain = domains.map(|vs| expand_values(vs, content_kinds_for_domain));
+    let by_work_form = work_forms.map(|vs| expand_values(vs, content_kinds_for_work_form));
+
+    let mut out = query.clone();
+    out.filters.remove("domain");
+    out.filters.remove("workForm");
+    if out.filters.contains_key("contentKind") {
+        return Some(out);
+    }
+
+    let mut kinds: Vec<&'static str> = match (by_domain, by_work_form) {
+        (Some(d), Some(w)) => d.into_iter().filter(|k| w.contains(k)).collect(),
+        (Some(d), None) => d,
+        (None, Some(w)) => w,
+        (None, None) => unreachable!("guarded above"),
+    };
+    // Domain-ambiguous kinds come along whenever the expansion is non-empty
+    // — see [`WRITER_SUPPLIED_DOMAIN_KINDS`]. Skipped when nothing mapped,
+    // so an unknown value still expands to nothing and leaves the filter
+    // out entirely (below) rather than narrowing to `contentKind:pack`.
+    if !kinds.is_empty() {
+        for k in WRITER_SUPPLIED_DOMAIN_KINDS
+            .iter()
+            .chain(WRITER_SUPPLIED_WORK_FORM_KINDS.iter())
+        {
+            if !kinds.contains(k) {
+                kinds.push(k);
+            }
+        }
+    }
+    // An unknown value — or two axes with no kind in common — expands to
+    // nothing. Inserting an empty alternation would drop every record at the
+    // plugin; leaving the filter out lets the plugin answer and the post-stamp
+    // check do the (correct, empty) filtering.
+    if !kinds.is_empty() {
+        out.filters.insert(
+            "contentKind".to_string(),
+            kinds.into_iter().map(|k| k.to_string()).collect(),
+        );
+    }
+    Some(out)
+}
+
+/// Deprecated alias for [`expand_routing_filters`], kept so a caller pinned to
+/// an older SDK keeps compiling. It expands `workForm:` too — the name is the
+/// only thing that is stale.
+#[deprecated(note = "renamed to expand_routing_filters; it now expands workForm: as well")]
+pub fn expand_domain_filter(
+    query: &crate::query::GatewayQuery,
+) -> Option<crate::query::GatewayQuery> {
+    expand_routing_filters(query)
+}
+
+fn expand_values(
+    values: &[String],
+    expand: fn(&str) -> Vec<&'static str>,
+) -> Vec<&'static str> {
+    let mut out: Vec<&'static str> = Vec::new();
+    for v in values {
+        for k in expand(v) {
+            if !out.contains(&k) {
+                out.push(k);
+            }
+        }
+    }
+    out
+}
+
+/// Stamp `domain` on a field map that already carries a `contentKind`.
+///
+/// The convention from METADATA_KEYS.md §1: **whoever writes `contentKind`
+/// writes `domain` in the same breath**. An existing `domain` is never
+/// overwritten — a writer that knows better than the table (a `pack`, say) has
+/// already set it.
+pub fn stamp_domain(fields: &mut std::collections::BTreeMap<String, String>) {
+    stamp(fields, "domain", domain_for_content_kind);
+}
+
+/// Stamp `workForm` the same way, from the same `contentKind`. Call it
+/// wherever [`stamp_domain`] is called — the registry treats the two as one
+/// breath.
+pub fn stamp_work_form(fields: &mut std::collections::BTreeMap<String, String>) {
+    stamp(fields, "workForm", work_form_for_content_kind);
+}
+
+fn stamp(
+    fields: &mut std::collections::BTreeMap<String, String>,
+    key: &str,
+    derive: fn(&str) -> Option<&'static str>,
+) {
+    if fields.contains_key(key) {
+        return;
+    }
+    let Some(kind) = fields.get("contentKind").cloned() else {
+        return;
+    };
+    if let Some(value) = derive(&kind) {
+        fields.insert(key.to_string(), value.to_string());
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::collections::BTreeMap;
+
+    #[test]
+    fn kinds_map_to_their_domain() {
+        assert_eq!(domain_for_content_kind("movie"), Some("screen"));
+        assert_eq!(domain_for_content_kind("episode"), Some("screen"));
+        assert_eq!(domain_for_content_kind("track"), Some("music"));
+        // The case that proves medium and domain are different axes.
+        assert_eq!(domain_for_content_kind("musicVideo"), Some("music"));
+        // The case that proves the player does not decide the domain.
+        assert_eq!(domain_for_content_kind("audiobook"), Some("literature"));
+    }
+
+    #[test]
+    fn film_and_tv_are_one_domain_now() {
+        // The merge (METADATA_KEYS.md §14.17): meta-watch's wall is one term.
+        assert_eq!(
+            domain_for_content_kind("movie"),
+            domain_for_content_kind("series")
+        );
+        // ...and the split it used to carry lives here instead.
+        assert_eq!(work_form_for_content_kind("movie"), Some("standalone"));
+        assert_eq!(work_form_for_content_kind("series"), Some("serial"));
+        assert_eq!(work_form_for_content_kind("episode"), Some("serial"));
+    }
+
+    #[test]
+    fn work_form_is_not_a_screen_only_axis() {
+        // The point of the key: it means the same thing in every domain.
+        assert_eq!(work_form_for_content_kind("comic"), Some("serial"));
+        assert_eq!(work_form_for_content_kind("book"), Some("standalone"));
+        assert_eq!(work_form_for_content_kind("album"), Some("standalone"));
+    }
+
+    #[test]
+    fn the_spoken_domain_is_gone() {
+        // Retired unused. The kinds stay reserved with no domain until the PR
+        // that writes them picks one.
+        assert_eq!(domain_for_content_kind("podcast"), None);
+        assert_eq!(domain_for_content_kind("podcastEpisode"), None);
+        assert!(content_kinds_for_domain("spoken").is_empty());
+    }
+
+    #[test]
+    fn pack_has_no_derivable_domain_or_work_form() {
+        assert_eq!(domain_for_content_kind("pack"), None);
+        assert_eq!(work_form_for_content_kind("pack"), None);
+    }
+
+    #[test]
+    fn unknown_kind_is_none_not_a_guess() {
+        assert_eq!(domain_for_content_kind("hologram"), None);
+        assert_eq!(work_form_for_content_kind("hologram"), None);
+    }
+
+    #[test]
+    fn expansion_is_the_inverse() {
+        let music = content_kinds_for_domain("music");
+        assert!(music.contains(&"track"));
+        assert!(music.contains(&"musicVideo"));
+        assert!(!music.contains(&"audiobook"));
+        for kind in content_kinds_for_domain("literature") {
+            assert_eq!(domain_for_content_kind(kind), Some("literature"));
+        }
+        for kind in content_kinds_for_work_form("serial") {
+            assert_eq!(work_form_for_content_kind(kind), Some("serial"));
+        }
+    }
+
+    #[test]
+    fn screen_expands_to_every_rung_not_just_the_first() {
+        // The regression the merge creates for any caller reading `.first()`.
+        let screen = content_kinds_for_domain("screen");
+        assert!(screen.contains(&"movie"));
+        assert!(screen.contains(&"series"));
+        assert!(screen.contains(&"episode"));
+    }
+
+    fn q(filters: &[(&str, &[&str])]) -> crate::query::GatewayQuery {
+        crate::query::GatewayQuery {
+            raw_text: String::new(),
+            free_text: String::new(),
+            filters: filters
+                .iter()
+                .map(|(k, vs)| {
+                    (
+                        k.to_string(),
+                        vs.iter().map(|v| v.to_string()).collect::<Vec<_>>(),
+                    )
+                })
+                .collect(),
+            ranges: Vec::new(),
+            negations: Vec::new(),
+        }
+    }
+
+    #[test]
+    fn no_routing_filter_is_left_untouched() {
+        assert!(expand_routing_filters(&q(&[("fileType", &["video"])])).is_none());
+    }
+
+    #[test]
+    fn domain_becomes_the_content_kinds_it_covers() {
+        let out = expand_routing_filters(&q(&[("domain", &["literature"])])).unwrap();
+        // The plugin never sees `domain:` — that is the whole point.
+        assert!(!out.filters.contains_key("domain"));
+        let kinds = out.filters.get("contentKind").unwrap();
+        assert!(kinds.contains(&"book".to_string()));
+        assert!(kinds.contains(&"audiobook".to_string()));
+        assert!(!kinds.contains(&"track".to_string()));
+    }
+
+    #[test]
+    fn work_form_alone_also_expands() {
+        let out = expand_routing_filters(&q(&[("workForm", &["serial"])])).unwrap();
+        assert!(!out.filters.contains_key("workForm"));
+        let kinds = out.filters.get("contentKind").unwrap();
+        assert!(kinds.contains(&"episode".to_string()));
+        assert!(kinds.contains(&"comic".to_string()));
+        assert!(!kinds.contains(&"movie".to_string()));
+    }
+
+    #[test]
+    fn the_two_axes_intersect_they_do_not_union() {
+        let out = expand_routing_filters(&q(&[
+            ("domain", &["screen"][..]),
+            ("workForm", &["serial"][..]),
+        ]))
+        .unwrap();
+        let kinds = out.filters.get("contentKind").unwrap();
+        assert!(kinds.contains(&"series".to_string()));
+        assert!(kinds.contains(&"episode".to_string()));
+        // The union would have dragged the whole film corpus in.
+        assert!(!kinds.contains(&"movie".to_string()));
+        // A `serial` comic is in `literature`, not on meta-watch's wall.
+        assert!(!kinds.contains(&"comic".to_string()));
+    }
+
+    #[test]
+    fn an_explicit_content_kind_filter_wins() {
+        let out = expand_routing_filters(&q(&[
+            ("domain", &["music"][..]),
+            ("contentKind", &["track"][..]),
+        ]))
+        .unwrap();
+        assert_eq!(
+            out.filters.get("contentKind").map(Vec::as_slice),
+            Some(&["track".to_string()][..])
+        );
+    }
+
+    #[test]
+    fn expansion_carries_the_writer_supplied_kinds() {
+        // `pack` has no domain in the table (a season pack and an album are the
+        // same structural thing), so the writer stamps one. Leaving it out of
+        // the alternation would make a `domain:screen` pre-filter drop the whole
+        // torrent-pack corpus, which `record_matches` would then never see.
+        let out = expand_routing_filters(&q(&[("domain", &["screen"])])).unwrap();
+        let kinds = out.filters.get("contentKind").unwrap();
+        assert!(kinds.contains(&"episode".to_string()));
+        assert!(kinds.contains(&"pack".to_string()));
+        // ...and it rides along on the `workForm` axis too, exactly once.
+        let out = expand_routing_filters(&q(&[("workForm", &["serial"])])).unwrap();
+        let kinds = out.filters.get("contentKind").unwrap();
+        assert_eq!(kinds.iter().filter(|k| *k == "pack").count(), 1);
+    }
+
+    #[test]
+    fn unknown_value_adds_no_alternation() {
+        // An empty alternation would drop every record at the plugin; the
+        // post-stamp check does the (correct, empty) filtering.
+        let out = expand_routing_filters(&q(&[("domain", &["hologram"])])).unwrap();
+        // Not even `pack`: a lone `contentKind:pack` would be a NARROWING of a
+        // filter that should widen to nothing.
+        assert!(!out.filters.contains_key("contentKind"));
+    }
+
+    #[test]
+    fn two_axes_with_nothing_in_common_widen_rather_than_narrow() {
+        // No music kind is `serial`. The pre-filter drops out; the post-stamp
+        // check still enforces both terms.
+        let out = expand_routing_filters(&q(&[
+            ("domain", &["music"][..]),
+            ("workForm", &["serial"][..]),
+        ]))
+        .unwrap();
+        assert!(!out.filters.contains_key("contentKind"));
+    }
+
+    #[test]
+    fn stamp_fills_in_and_never_overwrites() {
+        let mut f: BTreeMap<String, String> = BTreeMap::new();
+        f.insert("contentKind".into(), "episode".into());
+        stamp_domain(&mut f);
+        stamp_work_form(&mut f);
+        assert_eq!(f.get("domain").map(String::as_str), Some("screen"));
+        assert_eq!(f.get("workForm").map(String::as_str), Some("serial"));
+
+        // A pack writer that already knows its context keeps it.
+        let mut p: BTreeMap<String, String> = BTreeMap::new();
+        p.insert("contentKind".into(), "pack".into());
+        p.insert("domain".into(), "music".into());
+        p.insert("workForm".into(), "standalone".into());
+        stamp_domain(&mut p);
+        stamp_work_form(&mut p);
+        assert_eq!(p.get("domain").map(String::as_str), Some("music"));
+        assert_eq!(p.get("workForm").map(String::as_str), Some("standalone"));
+
+        // No contentKind → nothing invented.
+        let mut n: BTreeMap<String, String> = BTreeMap::new();
+        stamp_domain(&mut n);
+        stamp_work_form(&mut n);
+        assert!(n.get("domain").is_none());
+        assert!(n.get("workForm").is_none());
+    }
+}

src/hash.rs

@@ -248,8 +248,12 @@ fn decode_hex_id(id: &str) -> Option<Vec<u8>> {
 ///   merge (a TMDB and a MyAnimeList locator on one meta-core record) safe.
 pub const CARD_LOCATOR_CODEC: u64 = 0x1007;
 
-/// Digest byte ceiling for a card locator, matching meta-share's
-/// `MAX_MULTIHASH_SIZE` — its `CidGeneric<64>` rejects a longer multihash.
+/// Digest byte ceiling for the locators that still carry one — `yt-video`
+/// (via [`kinded_locator_cid`]) and `ext-play`. Matches meta-share's
+/// `MAX_MULTIHASH_SIZE`, whose `CidGeneric<64>` rejects a longer multihash.
+///
+/// ⚠ **[`compute_card_cid`] is deliberately NOT subject to this** — see its
+/// doc. The name is kept because both remaining users were written against it.
 const CARD_LOCATOR_MAX_DIGEST: usize = 64;
 
 /// Encode a self-describing **card locator** CID from a metadata source and
@@ -270,8 +274,28 @@ const CARD_LOCATOR_MAX_DIGEST: usize = 64;
 /// operation driven by an explicit cross-source id mapping — never inferred
 /// here (see `meta-gateway/docs/others/card-tier-search.md` §9).
 ///
-/// Returns `None` when `source` is empty or the digest would overflow the
-/// multihash budget — the caller drops that card.
+/// # No length ceiling, deliberately
+///
+/// A CIDv1 digest length is a varint, so the wire format imposes no limit; the
+/// 64-byte figure elsewhere in this file is Rust's fixed-size `CidGeneric<64>`,
+/// which meta-share needs only because beetswap is
+/// `Behaviour<const MAX_MULTIHASH_SIZE, B>`. A card is never bitswap content
+/// (seeding is gated on sha2-256), so that ceiling does not apply — exactly the
+/// reasoning `METADATA_KEYS.md` §2.1 already records for the `url` locator,
+/// which ships URLs past it today. meta-core's Go `Decode` hand-parses varints
+/// with no cap and reads these correctly.
+///
+/// This is load-bearing for URL-shaped ids: a card keyed on a work's own
+/// address (`("weebcentral.com", "/series/…/some-long-slug")`) runs to ~88
+/// bytes, and capping would silently drop the card rather than mint it.
+///
+/// ⚠ The one consumer that still cares is meta-share's `cid_rank`, which parses
+/// through `MsCid::from_str`. A locator it cannot parse scores `RANK_UNKNOWN`
+/// instead of `RANK_LOCATOR`; harmless for a card (its record carries one CID,
+/// so it wins the canonical election at any rank) but pinned by a golden vector
+/// in `cid-rank-vectors.json` so the two implementations cannot drift unseen.
+///
+/// Returns `None` only when `source` or `id` is empty.
 pub fn compute_card_cid(source: &str, id: &str) -> Option<String> {
     if source.is_empty() || id.is_empty() {
         return None;
@@ -284,9 +308,6 @@ pub fn compute_card_cid(source: &str, id: &str) -> Option<String> {
     write_pb_varint(source_b.len() as u64, &mut digest);
     digest.extend_from_slice(source_b);
     digest.extend_from_slice(id_b);
-    if digest.len() > CARD_LOCATOR_MAX_DIGEST {
-        return None;
-    }
 
     // CIDv1: [version=0x01][codec varint][mh code=0x00 identity][len varint][digest]
     let mut wire = Vec::with_capacity(1 + 3 + 2 + digest.len());
@@ -1067,19 +1088,88 @@ mod tests {
         assert_eq!(&digest[5..], b"tv:95479");
     }
 
-    /// Empty inputs are rejected rather than encoded as an ambiguous locator,
-    /// and an id past the 64-byte multihash budget (meta-share's
-    /// `CidGeneric<64>`) returns `None` so the caller drops the card instead of
-    /// emitting a cid that peer would refuse to parse.
+    /// Empty inputs are rejected rather than encoded as an ambiguous locator.
     #[test]
-    fn card_cid_rejects_empty_and_oversized() {
+    fn card_cid_rejects_empty_halves() {
         assert!(compute_card_cid("", "tv:1").is_none());
         assert!(compute_card_cid("tmdb", "").is_none());
-        let huge = "x".repeat(CARD_LOCATOR_MAX_DIGEST);
-        assert!(compute_card_cid("tmdb", &huge).is_none());
-        // Exactly at the ceiling still encodes.
-        let fits = "x".repeat(CARD_LOCATOR_MAX_DIGEST - 5); // varint(4) + "tmdb"
-        assert!(compute_card_cid("tmdb", &fits).is_some());
+    }
+
+    /// ⚠ A card locator has **no length ceiling**, and this is the test that
+    /// says so on purpose — it used to assert the opposite.
+    ///
+    /// The 64-byte figure is meta-share's `CidGeneric<64>` bitswap alias, and a
+    /// card is never bitswap content. Capping here would silently drop exactly
+    /// the cards a URL-shaped identity exists to mint: a `weebcentral.com` work
+    /// path digests to ~88 bytes. Same reasoning `METADATA_KEYS.md` §2.1
+    /// already records for the `url` locator.
+    #[test]
+    fn card_cid_has_no_length_ceiling() {
+        let long_id = "/series/01J76XYGF1RKSPWA4TQ6GGSVFV/\
+                       Ive-Been-Killing-Slimes-for-300-Years-The-Red-Dragon-Academy-for-Girls";
+        let cid = compute_card_cid("weebcentral.com", long_id).expect("no ceiling");
+        let (source, id) = split_card_digest(&cid);
+        assert!(
+            source.len() + id.len() > CARD_LOCATOR_MAX_DIGEST,
+            "fixture must actually exceed the old cap, got {}",
+            source.len() + id.len()
+        );
+        assert_eq!(source, "weebcentral.com");
+        assert_eq!(id, long_id);
+    }
+
+    /// The host-form identity: the source slot names the site that *owns* the
+    /// work, never the tool that reached it. Pinned as a literal because
+    /// `meta-read`'s `card_cid::encode` carries the mirrored assertion — the two
+    /// addressing one work differently is the failure the whole scheme cannot
+    /// survive.
+    #[test]
+    fn host_form_card_cid_golden_vector() {
+        let cid = compute_card_cid("mangadex.org", "/manga/b0b721ff-c388-4486-aa0f-c2b0bb321512")
+            .expect("card cid");
+        assert_eq!(
+            cid,
+            "bagdsaabybrwwc3thmfsgk6bon5zgol3nmfxgoyjpmiygenzsgftgmlldgm4dqljugq4dmllbmeygmlldgjrdaytcgmzdcnjrgi"
+        );
+    }
+
+    /// `varint(source_len) ‖ source ‖ id` back out of a card locator, so the
+    /// tests above can assert on the halves without a decoder in this crate.
+    fn split_card_digest(cid: &str) -> (String, String) {
+        let raw = base32_lower_decode(&cid[1..]);
+        let mut i = 0usize;
+        let mut rd = || {
+            let (mut n, mut sh) = (0u64, 0u32);
+            loop {
+                let b = raw[i];
+                i += 1;
+                n |= u64::from(b & 0x7f) << sh;
+                if b & 0x80 == 0 {
+                    return n;
+                }
+                sh += 7;
+            }
+        };
+        assert_eq!(rd(), 1, "CIDv1");
+        assert_eq!(rd(), CARD_LOCATOR_CODEC);
+        assert_eq!(rd(), 0, "identity multihash");
+        let len = rd() as usize;
+        let digest = &raw[i..i + len];
+        let mut j = 0usize;
+        let (mut sl, mut sh) = (0usize, 0u32);
+        loop {
+            let b = digest[j];
+            j += 1;
+            sl |= usize::from(b & 0x7f) << sh;
+            if b & 0x80 == 0 {
+                break;
+            }
+            sh += 7;
+        }
+        (
+            String::from_utf8(digest[j..j + sl].to_vec()).unwrap(),
+            String::from_utf8(digest[j + sl..].to_vec()).unwrap(),
+        )
     }
 
     // ---- nzb-posting (0x1003) — the dedup contract -----------------------

src/lib.rs

@@ -25,6 +25,7 @@ pub mod budget;
 pub mod cache;
 pub mod common;
 pub mod config;
+pub mod domain;
 pub mod enrich;
 pub mod filename_meta;
 pub mod hash;