swarm-controller: accept the legacy pre-alignment email in the lockdown guard

disable_repo_creation's ownership guard now matches either the aligned
{agent}@hyperhive.local email or the legacy {agent}@hive.local one
hive-c0re::forge::users::ensure_user_exists used before its own
ensure_user_email alignment pass existed. That pass only runs on the
forge-host hive, and only once it has a core token and has ticked, so a
real pre-existing agent can still carry the old email when this node reads
it. Without this, the guard would bail "not this agent's" on a genuine
agent during that rollout window (argus, round 2).

Verified separately (not a code change): swarm-controller's forge account
is a site admin (created with --admin), and Forgejo's
convert.toUser/ToUser only hides an account's email when the caller isn't
the admin and isn't the account itself (services/convert/user.go), so
user_get already returns the real email regardless of hide_email on the
target account. No endpoint change needed for that half of the review.

nix/checks.nix

@@ -156,7 +156,24 @@ in
   # per-container toplevels stay fully cached.
   cargo-test = craneLib.cargoTest {
     src = cleanSrc;
-    inherit cargoArtifacts nativeBuildInputs;
+    inherit cargoArtifacts;
+    # `swarm-controller`'s forge tests build a real `forgejo_api::Forgejo`
+    # (hence a real `reqwest::Client`) against a loopback stub server, never
+    # the real forge — but `reqwest`/`rustls` still resolves roots through
+    # `rustls-native-certs` at *client-build* time, unconditionally, even
+    # though every request that client ever sends is plain `http://` to
+    # `127.0.0.1`. The nix build sandbox has no system CA store, so that
+    # resolution finds zero certs and `ClientBuilder::build()` itself fails
+    # with "No CA certificates were loaded from the system" — the tests
+    # never get as far as making a request. Same root cause the runtime
+    # deployment already works around (see `nix/host-modules/swarm-
+    # controller.nix`'s `caTrust` comment) and the same fix: give
+    # `rustls-native-certs` something to find via `SSL_CERT_FILE`. The
+    # bundle's actual contents don't matter here — nothing in these tests
+    # ever presents or verifies a real certificate — only that the store is
+    # non-empty.
+    nativeBuildInputs = nativeBuildInputs ++ [ pkgs.cacert ];
+    SSL_CERT_FILE = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
     pname = "hyperhive-workspace";
     version = "0.1.0";
     cargoTestExtraArgs = "--workspace";

swarm-controller/src/forge.rs

@@ -20,9 +20,9 @@ use forgejo_api::structs::{
     AddCollaboratorOption, AddCollaboratorOptionPermission, ChangeFileOperation,
     ChangeFileOperationOperation, ChangeFilesOptions, CreateBranchProtectionOption,
     CreateHookOption, CreateHookOptionConfig, CreateHookOptionType, CreateRepoOption,
-    CreateUserOption, IssueListIssuesQuery, IssueListIssuesQueryState, IssueListIssuesQueryType,
+    CreateUserOption, EditUserOption, IssueListIssuesQuery, IssueListIssuesQueryState,
-    RepoGetContentsQuery, RepoListPullRequestsQuery, RepoListPullRequestsQueryState,
+    IssueListIssuesQueryType, RepoGetContentsQuery, RepoListPullRequestsQuery,
-    RepoSearchQuery, StateType,
+    RepoListPullRequestsQueryState, RepoSearchQuery, StateType,
 };
 use forgejo_api::{ApiErrorKind, Auth, Forgejo, ForgejoError};
 use futures_util::{StreamExt as _, TryStreamExt as _};
@@ -361,8 +361,8 @@ impl Client {
             .await
     }
 
-    /// Ensure `agent` exists as a Forgejo user account — the whole job of
+    /// Ensure `agent` exists as a Forgejo user account that cannot create
-    /// the `CreateForgeUser` node, and the fix for the "user does not
+    /// repos — the whole job of the `CreateForgeUser` node, and the fix for the "user does not
     /// exist" failure `AddRepoMember` hit before this node existed: adding
     /// a nonexistent user as a collaborator is a Forgejo validation error,
     /// not an idempotent no-op, so something has to create the account
@@ -373,12 +373,8 @@ impl Client {
     /// `forgejo admin` CLI, which assumes co-location with the forge host.
     /// This daemon has no such assumption — like every other call in this
     /// file, it only ever talks to the forge over HTTP — so this goes through
-    /// `admin_create_user` instead.
+    /// `admin_create_user` instead. The password is a throwaway: 32 random
-    ///
+    /// bytes, generated once, never persisted or read again (see
-    /// The password itself is a throwaway: 32 random bytes, generated once,
-    /// never persisted anywhere, and never needed again (unlike
-    /// `hive-c0re`'s CLI path, which can ask forgejo to `--random-password`
-    /// on its own, the HTTP admin API requires a real value up front — see
     /// [`crate::webhook::generate_hex_secret`], reused here for the same
     /// reason a webhook secret and this password are both "32 random bytes
     /// nothing reads back").
@@ -386,19 +382,79 @@ impl Client {
     /// Idempotent, same as [`Self::ensure_org_repo`]: 409 folds to success
     /// unconditionally, 422 only after a follow-up `user_get` confirms the
     /// user (see [`folds_into_success`] — not every 422 means it exists).
-    /// Deliberately does not align the account's email or disable its own
+    ///
-    /// repo-creation rights the way `hive-c0re`'s per-hive provisioning does
+    /// Then locks the account out of creating repos
-    /// (`ensure_user_email`, `ensure_repo_creation_disabled`) — this account
+    /// ([`Self::disable_repo_creation`]), whether it was just created or
-    /// only exists so `AddRepoMember` has something to add, and the owning
+    /// already existed. Nothing else does that for a swarm-created agent, so
-    /// hive's own provisioning pass self-heals both once the agent spawns.
+    /// a failure fails the node. Does not align the account's email the way
+    /// `hive-c0re`'s `ensure_user_email` does — cosmetic, not a guard.
     pub async fn ensure_agent_user(&self, agent: &str) -> Result<()> {
+        self.create_agent_user(agent).await?;
+        self.disable_repo_creation(agent).await
+    }
+
+    /// Set `max_repo_creation = 0` on `agent`'s account. Agents create repos
+    /// through the hive, never with their own token — a write-scoped token
+    /// can otherwise create and own a repo and self-merge in it, bypassing
+    /// the operator-only-merge policy. Existing repos are untouched; push,
+    /// PRs and clone keep working.
+    ///
+    /// The PATCH itself is unconditional rather than verify-then-patch:
+    /// Forgejo's API never returns `max_repo_creation` (it is a field of
+    /// `EditUserOption` only, not of `User`), so there is no current value
+    /// to compare against, and setting 0 on an account already at 0 is a
+    /// no-op. But `create_agent_user`'s idempotent fold only proves *some*
+    /// account named `agent` exists — a 409 folds with no read at all, and
+    /// a 422's follow-up `user_get` only confirms the username, not that
+    /// swarm-controller created it — so before that PATCH this reads the
+    /// account once and checks the one thing that *is* comparable: the
+    /// email. A match against either [`agent_email`] (what
+    /// `create_agent_user` itself sets) or [`legacy_agent_email`] (what
+    /// `hive-c0re::forge::users::ensure_user_exists` used before its own
+    /// `ensure_user_email` alignment pass runs) counts as this agent's
+    /// account — the legacy value has to be accepted too, not just the
+    /// aligned one, because `ensure_user_email` only runs on the forge-host
+    /// hive and only once it has a core token and has ticked at least once,
+    /// so a real, existing legacy agent can still carry the old email when
+    /// this node reads it mid-rollout. A mismatch against both means the
+    /// name collided with an account this node didn't create, so it fails
+    /// the node rather than sending the PATCH (or silently skipping) to an
+    /// account nobody verified is agent-controlled.
+    async fn disable_repo_creation(&self, agent: &str) -> Result<()> {
+        let user = self
+            .api
+            .user_get(agent)
+            .await
+            .with_context(|| format!("read forge user {agent} before locking it down"))?;
+        let expected = agent_email(agent);
+        let legacy = legacy_agent_email(agent);
+        if !matches!(user.email.as_deref(), Some(e) if e == expected || e == legacy) {
+            anyhow::bail!(
+                "forge account `{agent}` exists but is not this agent's (email {:?}, expected \
+                 `{expected}` or the legacy `{legacy}`); refusing to lock it down",
+                user.email
+            );
+        }
+        self.api
+            .admin_edit_user(agent, repo_creation_lockdown(agent))
+            .await
+            .with_context(|| {
+                format!("disable repo creation for forge user {agent} (max_repo_creation = 0)")
+            })?;
+        tracing::info!(%agent, "swarm forge: disabled repo creation (max_repo_creation = 0)");
+        Ok(())
+    }
+
+    /// Create `agent`'s account. Idempotent: an existing user (409/422) is
+    /// folded into success, same as [`Self::ensure_org_repo`].
+    async fn create_agent_user(&self, agent: &str) -> Result<()> {
         let password = crate::webhook::generate_hex_secret()
             .context("generating a throwaway password for the agent's forge account")?;
         let res = self
             .api
             .admin_create_user(CreateUserOption {
                 created_at: None,
-                email: format!("{agent}@hyperhive.local"),
+                email: agent_email(agent),
                 full_name: None,
                 login_name: None,
                 must_change_password: Some(false),
@@ -1084,6 +1140,63 @@ fn initial_flake_nix() -> &'static str {
     "{\n  description = \"hyperhive agent\";\n  inputs = { };\n  outputs =\n    { self, ... }@inputs:\n    {\n      nixosModules.default = {\n        imports = [ ./agent.nix ];\n        _module.args.flakeInputs = builtins.removeAttrs inputs [ \"self\" ];\n      };\n    };\n}\n"
 }
 
+/// Canonical email for an agent's Forgejo account, set by
+/// [`Client::create_agent_user`] at creation and checked by
+/// [`Client::disable_repo_creation`] before it sends the account's PATCH. Same
+/// format string as `hive-c0re::forge::users::agent_email` — not called
+/// across the crate boundary (see this module's doc comment), but both
+/// creators (and `hive-c0re`'s `ensure_user_email`, which aligns older
+/// accounts to it) converge on this exact value, so it doubles as the
+/// marker that distinguishes an agent's own account from an unrelated one
+/// that happens to share its username.
+fn agent_email(agent: &str) -> String {
+    format!("{agent}@hyperhive.local")
+}
+
+/// The pre-alignment email `hive-c0re::forge::users::ensure_user_exists`
+/// gave an agent account before that crate's own `ensure_user_email`
+/// existed — see that function's doc comment ("Existing agents were
+/// created with `{name}@hive.local`; this corrects that"). Accepted by
+/// [`Client::disable_repo_creation`]'s guard alongside [`agent_email`]
+/// because `ensure_user_email`'s alignment PATCH only runs on the
+/// forge-host hive, and only after it has a core token and has ticked at
+/// least once, so a real legacy agent can still carry this value when this
+/// node reads it.
+fn legacy_agent_email(agent: &str) -> String {
+    format!("{agent}@hive.local")
+}
+
+/// The `admin_edit_user` body that sets `max_repo_creation = 0` on `agent`
+/// and nothing else. Same shape as `hive-c0re::forge::users`'
+/// `sparse_edit_user_option`: `login_name` + `source_id = 0` (local auth,
+/// which is what [`Client::create_agent_user`] creates) ride along because
+/// Forgejo resets `use_custom_avatar` on an admin edit that omits
+/// `login_name`; every other field is left unset so nothing else is touched.
+fn repo_creation_lockdown(agent: &str) -> EditUserOption {
+    EditUserOption {
+        active: None,
+        admin: None,
+        allow_create_organization: None,
+        allow_git_hook: None,
+        allow_import_local: None,
+        description: None,
+        email: None,
+        full_name: None,
+        hide_email: None,
+        location: None,
+        login_name: Some(agent.to_owned()),
+        max_repo_creation: Some(0),
+        must_change_password: None,
+        password: None,
+        prohibit_login: None,
+        pronouns: None,
+        restricted: None,
+        source_id: Some(0),
+        visibility: None,
+        website: None,
+    }
+}
+
 /// Whether a create-style call failed because the object already
 /// exists. Forgejo signals this as HTTP 409 (conflict) or 422
 /// (validation) — match both defensively, same as
@@ -1328,4 +1441,212 @@ mod tests {
             "new logic: correctly refuses to fold a 422 with no confirmed existence"
         );
     }
+
+    /// What [`stub_forge`] saw: method, path and JSON body of each request.
+    type Seen = std::sync::Arc<std::sync::Mutex<Vec<(String, String, serde_json::Value)>>>;
+
+    /// A stand-in forge on a loopback port — never the real one — answering
+    /// the admin user create (`POST`) with `create`, the pre-lockdown
+    /// `user_get` (`GET`) with `get`, and the admin user edit (`PATCH`) with
+    /// `edit` (status, JSON body each), and recording every request.
+    async fn stub_forge(
+        create: (u16, &'static str),
+        get: (u16, &'static str),
+        edit: (u16, &'static str),
+    ) -> (Client, Seen) {
+        use axum::http::{Method, StatusCode, Uri, header::CONTENT_TYPE};
+
+        let seen = Seen::default();
+        let recorded = seen.clone();
+        let app = axum::Router::new().fallback(
+            move |method: Method, uri: Uri, body: axum::body::Bytes| {
+                let recorded = recorded.clone();
+                async move {
+                    let json = serde_json::from_slice(&body).unwrap_or_default();
+                    recorded.lock().unwrap().push((
+                        method.to_string(),
+                        uri.path().to_owned(),
+                        json,
+                    ));
+                    let (status, body) = match method {
+                        Method::POST => create,
+                        Method::GET => get,
+                        Method::PATCH => edit,
+                        _ => (404, r#"{"message":"not stubbed"}"#),
+                    };
+                    let status = StatusCode::from_u16(status).unwrap();
+                    (status, [(CONTENT_TYPE, "application/json")], body)
+                }
+            },
+        );
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let url = url::Url::parse(&format!("http://{}/", listener.local_addr().unwrap())).unwrap();
+        tokio::spawn(async move { axum::serve(listener, app).await });
+        let api = Forgejo::new(Auth::Token("stub-token"), url).unwrap();
+        (Client { api }, seen)
+    }
+
+    /// The `PATCH` [`Client::ensure_agent_user`] sent, if any.
+    fn lockdown_patch(seen: &Seen, agent: &str) -> Option<serde_json::Value> {
+        let path = format!("/api/v1/admin/users/{agent}");
+        seen.lock()
+            .unwrap()
+            .iter()
+            .find(|(method, p, _)| method == "PATCH" && *p == path)
+            .map(|(_, _, body)| body.clone())
+    }
+
+    /// The email [`stub_forge`]'s `user_get` stub should answer with for an
+    /// account this agent actually owns — same value
+    /// [`Client::create_agent_user`] itself sets.
+    fn own_account_get(agent: &str) -> (u16, &'static str) {
+        // Leaked rather than borrowed: `stub_forge`'s `get` param needs
+        // `&'static str` (it moves into a `'static` axum handler), and this
+        // helper builds the body per-agent instead of hardcoding "alice".
+        (
+            200,
+            Box::leak(format!(r#"{{"email":"{agent}@hyperhive.local"}}"#).into_boxed_str()),
+        )
+    }
+
+    /// A freshly created agent account is locked out of repo creation by
+    /// this node itself — not left for a hive-level pass to catch later —
+    /// and the edit sets nothing beyond `max_repo_creation` plus the
+    /// `login_name` / `source_id` pair Forgejo needs to leave the rest alone.
+    #[tokio::test]
+    async fn a_created_agent_user_gets_repo_creation_disabled() {
+        let (client, seen) = stub_forge((201, "{}"), own_account_get("alice"), (200, "{}")).await;
+
+        client.ensure_agent_user("alice").await.unwrap();
+
+        let body = lockdown_patch(&seen, "alice").expect("no lockdown PATCH sent");
+        assert_eq!(body["max_repo_creation"], 0);
+        let set: Vec<&str> = body
+            .as_object()
+            .unwrap()
+            .iter()
+            .filter(|(_, v)| !v.is_null())
+            .map(|(k, _)| k.as_str())
+            .collect();
+        assert_eq!(set, ["login_name", "max_repo_creation", "source_id"]);
+        assert_eq!(body["login_name"], "alice");
+        assert_eq!(body["source_id"], 0);
+    }
+
+    /// An account that already existed is locked down too: the node is
+    /// re-run, and an account created before this lockdown existed must
+    /// not keep repo creation just because the create step folded to
+    /// success. 409 rather than 422 so the case doesn't hinge on how a 422
+    /// is disambiguated.
+    #[tokio::test]
+    async fn an_existing_agent_user_still_gets_repo_creation_disabled() {
+        let (client, seen) = stub_forge(
+            (409, r#"{"message":"user already exists"}"#),
+            own_account_get("alice"),
+            (200, "{}"),
+        )
+        .await;
+
+        client.ensure_agent_user("alice").await.unwrap();
+
+        let body = lockdown_patch(&seen, "alice").expect("no lockdown PATCH sent");
+        assert_eq!(body["max_repo_creation"], 0);
+    }
+
+    /// A refused lockdown fails the node with Forgejo's own message, rather
+    /// than warning and reporting the account as provisioned — that is
+    /// `hive-c0re`'s `ensure_repo_creation_disabled` shape, which leaves an
+    /// agent able to create and self-merge with nothing marked failed.
+    #[tokio::test]
+    async fn a_refused_lockdown_fails_the_node() {
+        let (client, _seen) = stub_forge(
+            (201, "{}"),
+            own_account_get("alice"),
+            (403, r#"{"message":"token does not have required scope"}"#),
+        )
+        .await;
+
+        let err = client.ensure_agent_user("alice").await.unwrap_err();
+
+        let msg = format!("{err:#}");
+        assert!(msg.contains("max_repo_creation"), "{msg}");
+        assert!(msg.contains("token does not have required scope"), "{msg}");
+    }
+
+    /// The guard this PR adds: a name collision with a pre-existing
+    /// non-agent account (or any account whose email isn't the
+    /// `{agent}@hyperhive.local` marker) must fail the node rather than
+    /// PATCH `max_repo_creation`/`source_id` onto an account nobody
+    /// verified this node created. 409 create-fold, same as
+    /// `an_existing_agent_user_still_gets_repo_creation_disabled` — the
+    /// fold itself is untouched by this PR; the fix lives in the read right
+    /// before the PATCH.
+    #[tokio::test]
+    async fn a_name_collision_with_a_non_agent_account_fails_without_patching() {
+        let (client, seen) = stub_forge(
+            (409, r#"{"message":"user already exists"}"#),
+            (200, r#"{"email":"someone@example.com"}"#),
+            (200, "{}"),
+        )
+        .await;
+
+        let err = client.ensure_agent_user("alice").await.unwrap_err();
+
+        let msg = format!("{err:#}");
+        assert!(msg.contains("alice"), "{msg}");
+        assert!(
+            msg.contains("not this agent's"),
+            "must name the collision, got: {msg}"
+        );
+        assert!(
+            lockdown_patch(&seen, "alice").is_none(),
+            "a collision must never reach the PATCH"
+        );
+    }
+
+    /// A legacy account `hive-c0re::forge::users::ensure_user_exists` (or
+    /// its `ensure_user_email` alignment pass) created carries the same
+    /// `{agent}@hyperhive.local` marker, plus the `login_name`/`source_id`
+    /// fields its own `sparse_edit_user_option` sets — this node must still
+    /// lock such an account down, not just ones it created itself.
+    #[tokio::test]
+    async fn a_legacy_hive_created_agent_account_still_gets_locked_down() {
+        let (client, seen) = stub_forge(
+            (409, r#"{"message":"user already exists"}"#),
+            (
+                200,
+                r#"{"id":42,"login":"alice","login_name":"alice","email":"alice@hyperhive.local","source_id":0}"#,
+            ),
+            (200, "{}"),
+        )
+        .await;
+
+        client.ensure_agent_user("alice").await.unwrap();
+
+        let body = lockdown_patch(&seen, "alice").expect("no lockdown PATCH sent");
+        assert_eq!(body["max_repo_creation"], 0);
+    }
+
+    /// argus's round-2 🟡: `hive-c0re`'s `ensure_user_email` alignment pass
+    /// (the thing that rewrites a legacy `{name}@hive.local` account to
+    /// `{name}@hyperhive.local`) only runs on the forge-host hive, and only
+    /// once it has a core token and has ticked — so a real, pre-existing
+    /// agent can still be sitting on the pre-alignment `@hive.local` email
+    /// when this node reads it. The guard must accept that value too, not
+    /// just the aligned one, or a real agent would fail with "not this
+    /// agent's" during the rollout window.
+    #[tokio::test]
+    async fn a_pre_alignment_legacy_email_still_gets_locked_down() {
+        let (client, seen) = stub_forge(
+            (409, r#"{"message":"user already exists"}"#),
+            (200, r#"{"email":"alice@hive.local"}"#),
+            (200, "{}"),
+        )
+        .await;
+
+        client.ensure_agent_user("alice").await.unwrap();
+
+        let body = lockdown_patch(&seen, "alice").expect("no lockdown PATCH sent");
+        assert_eq!(body["max_repo_creation"], 0);
+    }
 }