coin-grinder missing test for TOTAL_TRIES #33419

1. 
   yancyribbens commented at 4:24 pm on September 17, 2025: contributor

   The following (mutation) code can be remove from coin-grinder here without encountering a test failure

   0if (curr_try >= TOTAL_TRIES) {
   1    // Solution is not guaranteed to be optimal if `curr_try` hit TOTAL_TRIES
   2    result.SetAlgoCompleted(false);
   3    break;
   4}
   

   This ought to be a similar test to Test BnB attempt limit (TOTAL_TRIES)

2. 
   yancyribbens commented at 4:26 pm on September 17, 2025: contributor

   cc @murchandamus
3. fanquake added the label Tests on Sep 18, 2025
4. 
   brunoerg commented at 12:42 pm on September 18, 2025: contributor

   For reference: https://corecheck.dev/mutation/src/wallet/coinselection.cpp#L466 and https://corecheck.dev/mutation/src/wallet/coinselection.cpp#L468
5. 
   murchandamus commented at 7:55 pm on October 16, 2025: contributor

   Yeah, it would be good to add this test. If someone wants to work on this, I would like to suggest that they peruse the very similar test for BnB here: https://github.com/bitcoin/bitcoin/blob/e744fd1249bf9577274614eaf3997bf4bbb612ff/src/wallet/test/coinselection_tests.cpp#L166 And to understand what CoinGrinder is actually doing and how it work, I would suggest that prospective implementers peruse the PR that added CoinGrinder starting with this commit: https://github.com/bitcoin/bitcoin/pull/27877/commits/6cc9a46cd0f4ed80d4523bbef1508142e0c80d27
6. 
   yancyribbens commented at 1:20 am on October 24, 2025: contributor

   Something like this would work:

    0    {
    1        // #################################################################################################################
    2        // 8) Max iterations
    3        // #################################################################################################################
    4        CAmount target =  8 * COIN;
    5        int max_selection_weight = 3200; // WU
    6        const auto& res = CoinGrinder(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    7            CoinsResult doppelgangers;
    8            for (int i = 0; i < 19; ++i) {
    9                add_coin(doppelgangers, wallet, CAmount(1 * COIN + i), CFeeRate(0), 144, false, 0, true, 96 + i);
   10            } 
   11            return doppelgangers;
   12        });
   13        BOOST_CHECK(!res);
   14    }
   

Contributors
yancyribbens brunoerg murchandamus

Labels
Tests