From 1cce7aea29b0f9c795b4d6896df22c25cbc295c9 Mon Sep 17 00:00:00 2001
From: Jin Chen <jinchen1036@gmail.com>
Date: Tue, 8 Sep 2026 15:17:03 -0400
Subject: [PATCH] Fix index-out-of-range crash when searching the country
 picker
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country(for:) subscripted filteredCountries and countries directly. isFiltering is
derived from the search bar, so it flips on the keystroke, while filteredCountries
is only replaced when the throttled search work item lands 0.25s later. A table
view can therefore ask for a row index it read before the list changed, and the
subscript traps.

Reproduced on device in a release build:

    Fatal error: Index out of range
    CountryCodePickerViewController.country(for:)
    CountryCodePickerViewController.tableView(_:cellForRowAt:)
    -[_UIFilteredDataSource tableView:cellForRowAtIndexPath:]
    -[UITableView _createPreparedCellForGlobalRow:withIndexPath:willDisplay:]

country(for:) now returns an optional and both call sites guard. cellForRowAt
returns the dequeued cell unconfigured — the table view asks again after the
pending reload — and didSelectRowAt returns without notifying the delegate, so a
tap on a row that no longer exists cannot deliver the wrong country.

didSelectRowAt also now deselects before the guard, so the row does not stay
highlighted when the lookup misses.

country(for:) is internal and has no callers outside this file, so the signature
change is not source-breaking for clients.
---
 .../CountryCodePickerViewController.swift     | 26 ++++++++++++++++---
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/Sources/PhoneNumberKitUI/CountryCodePickerViewController.swift b/Sources/PhoneNumberKitUI/CountryCodePickerViewController.swift
index 50f25cd..81fd6ee 100644
--- a/Sources/PhoneNumberKitUI/CountryCodePickerViewController.swift
+++ b/Sources/PhoneNumberKitUI/CountryCodePickerViewController.swift
@@ -218,8 +218,22 @@ public class CountryCodePickerViewController: UITableViewController {
     
     // MARK: - Table view data source
 
-    func country(for indexPath: IndexPath) -> Country {
-        isFiltering ? filteredCountries[indexPath.row] : countries[indexPath.section][indexPath.row]
+    /// The country at `indexPath`, or `nil` if that row no longer exists.
+    ///
+    /// `isFiltering` is derived from the search bar, so it becomes true on the
+    /// keystroke, while `filteredCountries` is only replaced when the throttled
+    /// search work item lands 0.25s later. A table view can therefore ask for a row
+    /// index it read before the list changed, and subscripting it directly traps.
+    func country(for indexPath: IndexPath) -> Country? {
+        if isFiltering {
+            guard filteredCountries.indices.contains(indexPath.row) else { return nil }
+            return filteredCountries[indexPath.row]
+        }
+        guard countries.indices.contains(indexPath.section),
+              countries[indexPath.section].indices.contains(indexPath.row) else {
+            return nil
+        }
+        return countries[indexPath.section][indexPath.row]
     }
 
     override public func numberOfSections(in tableView: UITableView) -> Int {
@@ -238,7 +252,11 @@ public class CountryCodePickerViewController: UITableViewController {
             cell = tableView.dequeueReusableCell(withIdentifier: CountryCodePickerTableViewCell.reuseIdentifier, for: indexPath) as! CountryCodePickerTableViewCell
         }
         
-        let country = self.country(for: indexPath)
+        guard let country = self.country(for: indexPath) else {
+            // The row went away between the count and this call; the table view will
+            // ask again after the pending reload.
+            return cell
+        }
         cell.configure(with: country)
         cell.options = options.cellOptions
         return cell
@@ -278,8 +296,8 @@ public class CountryCodePickerViewController: UITableViewController {
     }
 
     override public func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
-        let country = self.country(for: indexPath)
         tableView.deselectRow(at: indexPath, animated: true)
+        guard let country = self.country(for: indexPath) else { return }
         delegate?.countryCodePickerViewControllerDidPickCountry(country)
     }