remove the unread forge-core-token at startup

hive-c0re/src/migrate.rs

@@ -69,6 +69,11 @@ pub async fn run() -> Result<()> {
         migrate_harness_files(name);
     }
 
+    match remove_core_token(&crate::paths::state_root()) {
+        Ok(true) => tracing::info!("migration: removed the unread forge-core-token"),
+        Ok(false) => {}
+        Err(e) => tracing::warn!(error = ?e, "migration: removing the forge-core-token failed"),
+    }
     match remove_legacy_meta_git(&crate::paths::meta_root()) {
         Ok(true) => tracing::info!("migration: removed the legacy meta repo's .git"),
         Ok(false) => {}
@@ -174,6 +179,17 @@ fn remove_legacy_meta_git(meta: &Path) -> Result<bool> {
     }
 }
 
+/// Remove the forge admin token file an earlier hive left in `state`; nothing
+/// reads it. `true` when it was there.
+fn remove_core_token(state: &Path) -> Result<bool> {
+    let file = state.join("forge-core-token");
+    match std::fs::remove_file(&file) {
+        Ok(()) => Ok(true),
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(false),
+        Err(e) => Err(e).with_context(|| format!("removing {}", file.display())),
+    }
+}
+
 /// Remove the `meta` remote from the proposed repo at `dir`. `true` when it
 /// was there; a missing remote, or a `dir` that is no repo, is `false`.
 async fn remove_meta_remote(dir: &Path) -> Result<bool> {
@@ -342,6 +358,18 @@ mod tests {
         );
     }
 
+    #[test]
+    fn core_token_goes_once_and_its_neighbours_stay() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        std::fs::write(dir.path().join("forge-core-token"), "x").expect("write token");
+        std::fs::write(dir.path().join("forge-other"), "x").expect("write neighbour");
+
+        assert!(remove_core_token(dir.path()).expect("first"));
+        assert!(!dir.path().join("forge-core-token").exists());
+        assert!(dir.path().join("forge-other").exists(), "neighbour stays");
+        assert!(!remove_core_token(dir.path()).expect("second"), "no-op");
+    }
+
     #[tokio::test]
     async fn a_dir_that_is_no_repo_has_no_meta_remote() {
         let dir = tempfile::tempdir().expect("tempdir");