add review classifier rules for this repo

Eight classifications in .hyperhive/review-classifier.yml: no AI
advertising in commit messages, no committed secrets, no clippy
allow attributes, no debug leftovers, no dead code, tests with
behaviour changes, docs with operator-facing changes, one purpose per PR.

A swarm-controller test parses the real file so it can't rot, and the
rust source fileset in nix/rust.nix includes it so the test finds it
in the build sandbox.

.hyperhive/review-classifier.yml

@@ -0,0 +1,52 @@
+classifications:
+  - name: no-ads
+    description: >-
+      A commit message contains a co-authored-by line or other advertising
+      for an AI model, such as a "generated with" footer.
+    polarity: negative
+    threshold: 80
+  - name: no-secrets
+    description: >-
+      The diff adds a secret as literal text: a password, API key, access
+      token or private key. A path or name that points at a secret is not
+      one.
+    polarity: negative
+    threshold: 60
+  - name: no-lint-suppression
+    description: >-
+      The diff adds a Rust `#[allow(clippy::...)]` or `#![allow(clippy::...)]`
+      attribute instead of fixing what the lint reports.
+    polarity: negative
+    threshold: 70
+  - name: no-debug-leftovers
+    description: >-
+      The diff adds leftover debugging: a `dbg!` call, a print statement
+      that only inspects a value, or a block of commented-out code.
+    polarity: negative
+    threshold: 70
+  - name: no-dead-code
+    description: >-
+      The diff adds a function, type, option or module that nothing in the
+      diff calls, uses or registers, and that is not a test, a trait
+      implementation or public API.
+    polarity: negative
+    threshold: 75
+  - name: tests-with-behaviour
+    description: >-
+      Every change to how the code behaves comes with a new or updated test
+      that exercises it.
+    polarity: positive
+    threshold: 65
+  - name: docs-updated
+    description: >-
+      A change to what an operator or user sees, such as a command, flag,
+      option, endpoint, service or default, updates the matching page under
+      docs/ or the crate's README in the same diff.
+    polarity: positive
+    threshold: 65
+  - name: one-purpose
+    description: >-
+      Every change in the diff serves what the commit messages say the PR
+      does, and nothing unrelated is bundled in.
+    polarity: positive
+    threshold: 65

nix/rust.nix

@@ -35,9 +35,15 @@ rec {
   # `hyperhive-assets` derivation and are loaded by the binaries at
   # runtime from `$HIVE_ASSETS_DIR`. Net effect: only `*.rs` /
   # `*.toml` / `Cargo.lock` edits rebuild the rust derivations.
+  #
+  # The one other file in it is the repo's own review-classifier rules: a
+  # `swarm-controller` test parses them, so they must be in the sandbox.
   cleanSrc = lib.fileset.toSource {
     root = ../.;
-    fileset = craneLib.fileset.commonCargoSources ../.;
+    fileset = lib.fileset.unions [
+      (craneLib.fileset.commonCargoSources ../.)
+      ../.hyperhive/review-classifier.yml
+    ];
   };
 
   # The workspace's dependency tree, built once and cached as its own

swarm-controller/src/review_classifier.rs

@@ -1087,6 +1087,30 @@ classifications:
         assert_eq!(parse_rules(json_path, json.as_bytes()), Ok(want));
     }
 
+    #[test]
+    fn this_repos_own_rules_file_loads() {
+        let [yml_path, _] = RULES_PATHS;
+        let rules = parse_rules(
+            yml_path,
+            include_str!("../../.hyperhive/review-classifier.yml").as_bytes(),
+        )
+        .expect("the repo's rules file parses");
+        let names: Vec<_> = rules.iter().map(|c| c.name.as_str()).collect();
+        assert_eq!(
+            names,
+            [
+                "no-ads",
+                "no-secrets",
+                "no-lint-suppression",
+                "no-debug-leftovers",
+                "no-dead-code",
+                "tests-with-behaviour",
+                "docs-updated",
+                "one-purpose",
+            ]
+        );
+    }
+
     #[test]
     fn a_bad_rules_file_is_an_error_in_either_format() {
         let mut unknown_rule_field = datetime();