Replace allowed-refs.json with ref-statuses.json

As far as stable versions of Nix Flake Checker are concerned, a Nixpkgs
branch is considered supported if it meets the following criteria:

1. The branch is connected to a channel.
2. The branch’s status is not "unmaintained".
3. The branch’s status is not "beta".

Before this change, here’s how Nix Flake Checker would enforce those
criteria:

1. An API request was made to get a list of channels. Refs were only
   considered if they were on that list [1].
2. Refs would only get added to allowed-refs.json if their current field
   was set to "1" [1]. (The current field gets set to "0" for
   unmaintained channels and "1" for all other channels [2].)
3. The Nix Flake Checker project was careful about when it released
   updates that contained changes to allowed-refs.json. Specifically,
   updates to allowed-refs.json would stay in the main branch and
   not be released while Nixpkgs channels were in beta.

This change replaces allowed-refs.json with ref-statuses.json.
allowed-refs.json contained a list of supported Nixpkgs branches.
ref-statuses.json contains a list of Nixpkgs branches along with their
current status ("rolling", "beta", "stable", "deprecated" or
"unmaintained").

Here’s how Nix Flake Checker now enforces those same criteria:

1. Unchanged.
2. All channel branches get added to ref-statuses.json regardless of
   whether or not they’re supported. Nix Flake Checker checks if a
   branch’s status is "unmaintained" at runtime.
3. Nix Flake Checker checks if a branch’s status is "beta" at runtime.

The main motivation behind this change is to make it easier to create a
future commit. That future commit will allow users to access a branch’s
status via a CEL variable. As an added bonus, this change also makes it
so that the Nix Flake Checker project doesn’t have to be careful about
releasing updates while there’s Nixpkgs branches that are in beta.

[1]: src/allowed_refs.rs
[2]: <https://github.com/NixOS/infra/blob/ae9b362fe0d92cff76c0b5404d0bcec59dd322cb/build/pluto/prometheus/exporters/channel-exporter.py#L78>

.github/workflows/ref-statuses.yaml

@@ -0,0 +1,36 @@
+name: Check that ref statuses are up to date
+
+on:
+  schedule:
+    - cron: "0 0 * * *" # Daily
+
+jobs:
+  check-ref-statuses:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: DeterminateSystems/nix-installer-action@main
+
+      - uses: DeterminateSystems/magic-nix-cache-action@main
+
+      - name: Check ref statuses
+        run: |
+          nix develop --command cargo run --features ref-statuses -- --check-ref-statuses
+
+      - name: Update ref-statuses.json
+        if: failure()
+        run: |
+          ref_statuses_json=$(nix develop --command cargo run --features ref-statuses -- --get-ref-statuses | jq --sort-keys .)
+          echo "${ref_statuses_json}" > ref-statuses.json
+
+      - name: Create pull request
+        if: failure()
+        uses: peter-evans/create-pull-request@v6
+        with:
+          commit-message: Update ref-statuses.json to new valid Git refs list
+          title: Update ref-statuses.json
+          body: |
+            Nixpkgs has changed its list of maintained references. This PR updates `ref-statuses.json` to reflect that change.
+          branch: updated-ref-statuses
+          base: main

Cargo.toml

@@ -38,4 +38,4 @@ thiserror = { workspace = true }
 
 [features]
 default = []
-allowed-refs = []
+ref-statuses = []

flake.nix

@@ -91,10 +91,10 @@
               runtimeInputs = with pkgs; [ rustToolchain ];
               text = "cargo fmt --check";
             };
-            get-allowed-refs = pkgs.writeShellApplication {
-              name = "get-allowed-refs";
+            get-ref-statuses = pkgs.writeShellApplication {
+              name = "get-ref-statuses";
               runtimeInputs = with pkgs; [ rustToolchain ];
-              text = "cargo run --features allowed-refs -- --get-allowed-refs";
+              text = "cargo run --features ref-statuses -- --get-ref-statuses";
             };
           in
           pkgs.mkShell {
@@ -117,7 +117,7 @@
               check-rustfmt
 
               # Scripts
-              get-allowed-refs
+              get-ref-statuses
             ]) ++ pkgs.lib.optionals pkgs.stdenv.isDarwin (with pkgs.darwin.apple_sdk.frameworks; [ Security SystemConfiguration ]);
 
             env = {

ref-statuses.json

@@ -0,0 +1,11 @@
+{
+  "nixos-24.05": "deprecated",
+  "nixos-24.05-small": "deprecated",
+  "nixos-24.11": "stable",
+  "nixos-24.11-small": "stable",
+  "nixos-unstable": "rolling",
+  "nixos-unstable-small": "rolling",
+  "nixpkgs-24.05-darwin": "deprecated",
+  "nixpkgs-24.11-darwin": "stable",
+  "nixpkgs-unstable": "rolling"
+}

src/flake.rs

@@ -144,13 +144,14 @@ pub(super) fn num_days_old(timestamp: i64) -> i64 {
 
 #[cfg(test)]
 mod test {
+    use std::collections::HashMap;
     use std::path::PathBuf;
 
     use crate::{
         check_flake_lock,
         condition::evaluate_condition,
         issue::{Disallowed, Issue, IssueKind, NonUpstream},
-        FlakeCheckConfig, FlakeLock,
+        supported_refs, FlakeCheckConfig, FlakeLock,
     };
 
     #[test]
@@ -170,8 +171,9 @@ mod test {
             ),
         ];
 
-        let supported_refs: Vec<String> =
-            serde_json::from_str(include_str!("../allowed-refs.json")).unwrap();
+        let ref_statuses: HashMap<String, String> =
+            serde_json::from_str(include_str!("../ref-statuses.json")).unwrap();
+        let supported_refs = supported_refs(ref_statuses);
         let path = PathBuf::from("tests/flake.cel.0.lock");
 
         for (condition, expected) in cases {
@@ -201,8 +203,9 @@ mod test {
 
     #[test]
     fn clean_flake_locks() {
-        let allowed_refs: Vec<String> =
-            serde_json::from_str(include_str!("../allowed-refs.json")).unwrap();
+        let ref_statuses: HashMap<String, String> =
+            serde_json::from_str(include_str!("../ref-statuses.json")).unwrap();
+        let allowed_refs = supported_refs(ref_statuses);
         for n in 0..=7 {
             let path = PathBuf::from(format!("tests/flake.clean.{n}.lock"));
             let flake_lock = FlakeLock::new(&path).unwrap();
@@ -221,8 +224,9 @@ mod test {
 
     #[test]
     fn dirty_flake_locks() {
-        let allowed_refs: Vec<String> =
-            serde_json::from_str(include_str!("../allowed-refs.json")).unwrap();
+        let ref_statuses: HashMap<String, String> =
+            serde_json::from_str(include_str!("../ref-statuses.json")).unwrap();
+        let allowed_refs = supported_refs(ref_statuses);
         let cases: Vec<(&str, Vec<Issue>)> = vec![
             (
                 "flake.dirty.0.lock",
@@ -275,8 +279,9 @@ mod test {
 
     #[test]
     fn explicit_nixpkgs_keys() {
-        let allowed_refs: Vec<String> =
-            serde_json::from_str(include_str!("../allowed-refs.json")).unwrap();
+        let ref_statuses: HashMap<String, String> =
+            serde_json::from_str(include_str!("../ref-statuses.json")).unwrap();
+        let allowed_refs = supported_refs(ref_statuses);
         let cases: Vec<(&str, Vec<String>, Vec<Issue>)> = vec![(
             "flake.explicit-keys.0.lock",
             vec![String::from("nixpkgs"), String::from("nixpkgs-alt")],
@@ -303,8 +308,9 @@ mod test {
 
     #[test]
     fn missing_nixpkgs_keys() {
-        let allowed_refs: Vec<String> =
-            serde_json::from_str(include_str!("../allowed-refs.json")).unwrap();
+        let ref_statuses: HashMap<String, String> =
+            serde_json::from_str(include_str!("../ref-statuses.json")).unwrap();
+        let allowed_refs = supported_refs(ref_statuses);
         let cases: Vec<(&str, Vec<String>, String)> = vec![(
             "flake.clean.0.lock",
             vec![String::from("nixpkgs"), String::from("foo"), String::from("bar")],

src/main.rs

@@ -5,13 +5,14 @@ mod issue;
 mod summary;
 mod telemetry;
 
-#[cfg(feature = "allowed-refs")]
-mod allowed_refs;
+#[cfg(feature = "ref-statuses")]
+mod ref_statuses;
 
 use error::FlakeCheckerError;
 use flake::{check_flake_lock, FlakeCheckConfig};
 use summary::Summary;
 
+use std::collections::HashMap;
 use std::path::PathBuf;
 use std::process::ExitCode;
 
@@ -21,7 +22,7 @@ use parse_flake_lock::FlakeLock;
 use crate::condition::evaluate_condition;
 
 /// A flake.lock checker for Nix projects.
-#[cfg(not(feature = "allowed-refs"))]
+#[cfg(not(feature = "ref-statuses"))]
 #[derive(Parser)]
 #[command(author, version, about, long_about = None)]
 struct Cli {
@@ -96,10 +97,26 @@ struct Cli {
     condition: Option<String>,
 }
 
-#[cfg(not(feature = "allowed-refs"))]
+#[cfg(not(feature = "ref-statuses"))]
+pub(crate) fn supported_refs(ref_statuses: HashMap<String, String>) -> Vec<String> {
+    let mut return_value: Vec<String> = ref_statuses
+        .iter()
+        .filter_map(|(channel, status)| {
+            if *status != "unmaintained" && *status != "beta" {
+                Some(channel.clone())
+            } else {
+                None
+            }
+        })
+        .collect();
+    return_value.sort();
+    return_value
+}
+
+#[cfg(not(feature = "ref-statuses"))]
 fn main() -> Result<ExitCode, FlakeCheckerError> {
-    let allowed_refs: Vec<String> =
-        serde_json::from_str(include_str!("../allowed-refs.json")).unwrap();
+    let ref_statuses: HashMap<String, String> =
+        serde_json::from_str(include_str!("../ref-statuses.json")).unwrap();
 
     let Cli {
         no_telemetry,
@@ -134,6 +151,8 @@ fn main() -> Result<ExitCode, FlakeCheckerError> {
         fail_mode,
     };
 
+    let allowed_refs = supported_refs(ref_statuses);
+
     let issues = if let Some(condition) = &condition {
         evaluate_condition(&flake_lock, &nixpkgs_keys, condition, allowed_refs.clone())?
     } else {
@@ -168,61 +187,61 @@ fn main() -> Result<ExitCode, FlakeCheckerError> {
     Ok(ExitCode::SUCCESS)
 }
 
-#[cfg(feature = "allowed-refs")]
+#[cfg(feature = "ref-statuses")]
 #[derive(Parser)]
 struct Cli {
     // Check to make sure that Flake Checker is aware of the current supported branches.
     #[arg(long, hide = true)]
-    check_allowed_refs: bool,
+    check_ref_statuses: bool,
 
     // Check to make sure that Flake Checker is aware of the current supported branches.
     #[arg(long, hide = true)]
-    get_allowed_refs: bool,
+    get_ref_statuses: bool,
 }
 
-#[cfg(feature = "allowed-refs")]
+#[cfg(feature = "ref-statuses")]
 fn main() -> Result<ExitCode, FlakeCheckerError> {
     let Cli {
-        check_allowed_refs,
-        get_allowed_refs,
+        check_ref_statuses,
+        get_ref_statuses,
     } = Cli::parse();
 
-    if !get_allowed_refs && !check_allowed_refs {
-        panic!("You must select either --get-allowed-refs or --check-allowed-refs");
+    if !get_ref_statuses && !check_ref_statuses {
+        panic!("You must select either --get-ref-statuses or --check-ref-statuses");
     }
 
-    if get_allowed_refs {
-        match allowed_refs::fetch_allowed_refs() {
+    if get_ref_statuses {
+        match ref_statuses::fetch_ref_statuses() {
             Ok(refs) => {
                 let json_refs = serde_json::to_string(&refs)?;
                 println!("{json_refs}");
                 return Ok(ExitCode::SUCCESS);
             }
             Err(e) => {
-                println!("Error fetching allowed refs: {}", e);
+                println!("Error fetching ref statuses: {}", e);
                 return Ok(ExitCode::FAILURE);
             }
         }
     }
 
-    if check_allowed_refs {
-        let mut allowed_refs: Vec<String> =
-            serde_json::from_str(include_str!("../allowed-refs.json")).unwrap();
-
-        allowed_refs.sort();
+    if check_ref_statuses {
+        let mut ref_statuses: HashMap<String, String> =
+            serde_json::from_str(include_str!("../ref-statuses.json")).unwrap();
 
-        match allowed_refs::check_allowed_refs(allowed_refs) {
+        match ref_statuses::check_ref_statuses(ref_statuses) {
             Ok(equals) => {
                 if equals {
-                    println!("The allowed reference sets are up to date.");
+                    println!("The reference statuses sets are up to date.");
                     return Ok(ExitCode::SUCCESS);
                 } else {
-                    println!("The allowed reference sets are NOT up to date. Make sure to update.");
+                    println!(
+                        "The reference statuses sets are NOT up to date. Make sure to update."
+                    );
                     return Ok(ExitCode::FAILURE);
                 }
             }
             Err(e) => {
-                println!("Error checking allowed refs: {}", e);
+                println!("Error checking ref statuses: {}", e);
                 return Ok(ExitCode::FAILURE);
             }
         }