From c318366fab92a6e3f4e7953f116dcf3573dcfd90 Mon Sep 17 00:00:00 2001
From: vivekjami <j.vivekvamsi@gmail.com>
Date: Thu, 13 Nov 2025 00:06:09 +0530
Subject: [PATCH] Add validation for duplicate team entries

- Add explicit_leads() method to expose team leads
- Add validate_duplicate_team_entries() to check for duplicates
- Check leads, members, and alumni for duplicates
- Collect all errors for better developer experience
---
 src/schema.rs   |  4 ++++
 src/validate.rs | 62 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/src/schema.rs b/src/schema.rs
index 976eba916..feb1427d5 100644
--- a/src/schema.rs
+++ b/src/schema.rs
@@ -517,6 +517,10 @@ impl Team {
         self.people.alumni.as_ref().map_or(&[], Vec::as_slice)
     }
 
+    pub(crate) fn explicit_leads(&self) -> &[String] {
+        &self.people.leads
+    }
+
     pub(crate) fn contains_person(&self, data: &Data, person: &Person) -> Result<bool, Error> {
         let members = self.members(data)?;
         Ok(members.contains(person.github()))
diff --git a/src/validate.rs b/src/validate.rs
index 258568fa0..dcc9f9562 100644
--- a/src/validate.rs
+++ b/src/validate.rs
@@ -28,6 +28,7 @@ static CHECKS: &[Check<fn(&Data, &mut Vec<String>)>] = checks![
     validate_subteam_of,
     validate_team_leads,
     validate_team_members,
+    validate_duplicate_team_entries,
     validate_alumni,
     validate_archived_teams,
     validate_inactive_members,
@@ -236,6 +237,67 @@ fn validate_team_members(data: &Data, errors: &mut Vec<String>) {
     });
 }
 
+/// Helper for checking duplicates in a list
+fn check_duplicates<'a, I>(team_name: &str, label: &str, items: I) -> Result<(), Error>
+where
+    I: IntoIterator<Item = &'a str>,
+{
+    let mut seen = HashSet::new();
+    let mut duplicates = HashSet::new();
+
+    for item in items {
+        if !seen.insert(item) {
+            duplicates.insert(item);
+        }
+    }
+
+    if !duplicates.is_empty() {
+        let dup_list: Vec<&str> = duplicates.into_iter().collect();
+        bail!(
+            "team `{}` has duplicate {}: {}",
+            team_name,
+            label,
+            dup_list.join(", ")
+        );
+    }
+
+    Ok(())
+}
+
+/// Ensure no duplicate entries in team leads, members and alumni
+fn validate_duplicate_team_entries(data: &Data, errors: &mut Vec<String>) {
+    wrapper(data.teams(), errors, |team, errors| {
+        // Check leads for duplicates
+        if let Err(e) = check_duplicates(
+            team.name(),
+            "leads",
+            team.explicit_leads().iter().map(|s| s.as_str()),
+        ) {
+            errors.push(e.to_string());
+        }
+
+        // Check members for duplicates
+        if let Err(e) = check_duplicates(
+            team.name(),
+            "members",
+            team.explicit_members().iter().map(|m| m.github.as_str()),
+        ) {
+            errors.push(e.to_string());
+        }
+
+        // Check alumni for duplicates
+        if let Err(e) = check_duplicates(
+            team.name(),
+            "alumni",
+            team.explicit_alumni().iter().map(|a| a.github.as_str()),
+        ) {
+            errors.push(e.to_string());
+        }
+
+        Ok(())
+    });
+}
+
 /// Alumni team must consist only of automatically populated alumni from the other teams
 fn validate_alumni(data: &Data, errors: &mut Vec<String>) {
     let Some(alumni_team) = data.team("alumni") else {