# evolution-0001: EXDATE dedup O(E^2) in EDateTimeList

## Target
GNOME Evolution email/calendar client

## Severity
LOW-MEDIUM

## MOAD
0001 (CWE-407: Inefficient Algorithmic Complexity)

## Location
`src/calendar/gui/e-date-time-list.c` — `e_date_time_list_append()`
Called from `src/calendar/gui/e-comp-editor-page-recurrence.c` — `ecep_recurrence_fill_exception_widgets()`

## Description
`e_date_time_list_append()` deduplicates exception dates (EXDATE properties
on a recurring calendar event) using `g_list_find_custom()` on a GList.

When loading a recurring calendar event with E exception dates,
`ecep_recurrence_fill_exception_widgets()` calls append E times in a for loop.
Each call scans up to E-1 entries already stored: O(1) + O(2) + ... + O(E-1)
= O(E^2/2) total comparisons.

Real events can accumulate hundreds of exception dates over years (e.g., a
weekly recurring meeting with individual cancellations).

## Fix
Maintain a parallel `GHashTable` in `EDateTimeListPrivate` keyed on the
ISO date string (via `i_cal_time_as_ical_string()`). Membership test in
`e_date_time_list_append()` becomes O(1). Clear the hash table in
`e_date_time_list_clear()`.

## Speedup
| E | Ops (defective) | Ops (fixed) | Ratio |
|---|-----------------|-------------|-------|
| 50 | 1225 | 50 | 24.5x |
| 100 | 4950 | 100 | 49.5x |
| 200 | 19900 | 200 | 99.5x |
| 500 | 124750 | 500 | 249.5x |
| 1000 | 499500 | 1000 | 499.5x |

## MOAD-0002 (Intertangle)
`src/mail/mail-send-recv.c`: static globals `send_data`, `send_recv_dialog`,
`glob_ongoing_downsyncs` are shared mutable state across mail send/receive
operations and UI callbacks. No explicit mutex guards these. Architectural
MOAD-0002, no single-function patch.

## MOAD-0003
CLEAN. No ThreadLocal or GPrivate request-scoped identity leakage found.

## MOAD-0004
CLEAN. No credential values (passwords, tokens) logged verbatim. Debug
messages reference password operations by description only.

## MOAD-0005
CLEAN. Evolution uses GLib main loop (single UI thread). No concurrent
cache-get+put race conditions.