feat: adds error capping

lib/mv/membership/import/member_csv.ex

@@ -258,7 +258,17 @@ defmodule Mv.Membership.Import.MemberCSV do
     - `row_map` - Map with `:member` and `:custom` keys containing field values
   - `column_map` - Map of canonical field names (atoms) to column indices (for reference)
   - `custom_field_map` - Map of custom field IDs (strings) to column indices (for reference)
-  - `opts` - Optional keyword list for processing options
+  - `opts` - Optional keyword list for processing options:
+    - `:custom_field_lookup` - Map of custom field IDs to metadata (default: `%{}`)
+    - `:existing_error_count` - Number of errors already collected in previous chunks (default: `0`)
+    - `:max_errors` - Maximum number of errors to collect per import overall (default: `50`)
+
+  ## Error Capping
+
+  Errors are capped at `max_errors` per import overall. When the limit is reached:
+  - No additional errors are collected in the `errors` list
+  - Processing continues for all rows
+  - The `failed` count continues to increment correctly for all failed rows
 
   ## Returns
 
@@ -272,6 +282,11 @@ defmodule Mv.Membership.Import.MemberCSV do
       iex> custom_field_map = %{}
       iex> MemberCSV.process_chunk(chunk, column_map, custom_field_map)
       {:ok, %{inserted: 1, failed: 0, errors: []}}
+
+      iex> chunk = [{2, %{member: %{email: "invalid"}, custom: %{}}}]
+      iex> opts = [existing_error_count: 25, max_errors: 50]
+      iex> MemberCSV.process_chunk(chunk, %{}, %{}, opts)
+      {:ok, %{inserted: 0, failed: 1, errors: [%Error{}]}}
   """
   @spec process_chunk(
           list({pos_integer(), map()}),
@@ -281,16 +296,30 @@ defmodule Mv.Membership.Import.MemberCSV do
         ) :: {:ok, chunk_result()} | {:error, String.t()}
   def process_chunk(chunk_rows_with_lines, _column_map, _custom_field_map, opts \\ []) do
     custom_field_lookup = Keyword.get(opts, :custom_field_lookup, %{})
+    existing_error_count = Keyword.get(opts, :existing_error_count, 0)
+    max_errors = Keyword.get(opts, :max_errors, 50)
 
     {inserted, failed, errors} =
       Enum.reduce(chunk_rows_with_lines, {0, 0, []}, fn {line_number, row_map},
                                                         {acc_inserted, acc_failed, acc_errors} ->
+        current_error_count = existing_error_count + length(acc_errors)
+
         case process_row(row_map, line_number, custom_field_lookup) do
           {:ok, _member} ->
             {acc_inserted + 1, acc_failed, acc_errors}
 
           {:error, error} ->
-            {acc_inserted, acc_failed + 1, [error | acc_errors]}
+            new_acc_failed = acc_failed + 1
+
+            # Only collect errors if under limit
+            new_acc_errors =
+              if current_error_count < max_errors do
+                [error | acc_errors]
+              else
+                acc_errors
+              end
+
+            {acc_inserted, new_acc_failed, new_acc_errors}
         end
       end)