deterministic discards by SY3141 · Pull Request #362 · bcollazo/catanatron

SY3141 · 2026-03-20T04:57:10Z

implemented deterministic discards and updated the web UI to allow for resources to be selected to be discarded one by one.

#361

netlify · 2026-03-20T04:57:16Z

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bcollazo

Ok, pretty cool! Thanks for opening this PR!

Please don't be discouraged if we go back and forth a bit on the PR. I want to make sure I understand it fully and it goes in the direction I want for the codebase.

Could you include a video demo or so of the feature at work? Also explain a bit more how it may work? Maybe add a couple more examples like test_discard_possibilities_are_per_resource. Its a good example, but a simple one. I'd like to see a couple more to fully understand the picture. Thanks!

bcollazo · 2026-03-22T23:07:13Z


-    # TODO: None for now to avoid complexity, but should be Resource[].
-    DISCARD = "DISCARD"  # value is None
+    DISCARD = "DISCARD"  # value is Resource


Can you rename the action all together to DISCARD_RESOURCE? I think its going to help discern from a regular DISCARD.

did a grep search for every file where this action type is found and made the change

bcollazo · 2026-03-22T23:07:23Z

            abort(404)
    db.session.commit()
    game = pickle.loads(result.pickle_data)  # type: ignore
+    game.state._state_index = result.state_index


What is this for?

bcollazo · 2026-03-22T23:10:17Z

            self.state = State(players, catan_map, discard_limit=discard_limit)
            self.playable_actions = generate_playable_actions(self.state)

+    def __setstate__(self, state):


What is this for?

bcollazo · 2026-03-22T23:12:24Z


+    def __setstate__(self, state):
+        self.__dict__ = state
+        if not hasattr(self, "action_records"):


I think I see what we are trying to do here. Save old games? I rather have the simplicity in the code and have users treat games ephemerally (or tied to a version of the codebase).

was a patch for a database issue with the --step-db CLI flag that has since been resolved. Going to remove these above 3 legacy functions

bcollazo · 2026-03-22T23:13:51Z

    assert action.value == (SHEEP,)


+def test_action_from_json_discard():


bcollazo · 2026-03-22T23:17:06Z

Also, be sure to rebase and address any and all CI issues. Really want this to get in; I think its a strict improvement to what we have in place, and its pretty much needed for the UI to be usable.

bcollazo · 2026-03-23T15:26:43Z

Also, rebase or repoint the PR against bcollazo:main! master no longer! 👍 Thanks.

SY3141 · 2026-03-23T19:23:21Z

Also, rebase or repoint the PR against bcollazo:main! master no longer! 👍 Thanks.

should be pointing to main with this rebase: 99657b3. Let me know if I'm mistaken

bcollazo · 2026-03-25T00:27:43Z

Hey, I think something is still off. I still see its against "bcollazo:master", and the diff seems to suggest you'll introduce those changes in the snapshot (not related at all to deterministic cards). Feel free to close this one and re-open another if its easier! 👍

bcollazo

Hey, thanks for the work here. I have some changes I'd like to make before we merge. Please take a look! Thanks!

bcollazo · 2026-03-25T21:56:20Z

+        # Preserve historical DISCARD ordering so the rename does not reshuffle
+        # integer action ids for gym consumers.
+        return str(action).replace("DISCARD_RESOURCE", "DISCARD")
+


Is this for backwards compatibility as well? I wouldn't invest in it in the repo. I rather have it simple and treat it as a breaking change.

yup, this was for a deep learning bot in another repo trained on the 290 sized action space to work with the new 294 sized action space. Can remove this for the main repo though

bcollazo · 2026-03-25T21:57:01Z

+def discard_possibilities(state: State, color) -> List[Action]:
+    if state.discard_counts[color] <= 0:
+        return []
+
+    return [
+        Action(color, ActionType.DISCARD_RESOURCE, resource)
+        for resource in RESOURCES
+        if player_num_resource_cards(state, color, resource) > 0
+    ]


bcollazo · 2026-03-25T21:57:18Z

 The "result" field is polymorphic depending on the action_type.
 - ROLL: result is (int, int) 2 dice rolled
- DISCARD: result is List[Resource] discarded
+- DISCARD_RESOURCE: result is List[Resource] discarded in this action


result is a Resource* correct?

bcollazo · 2026-03-25T22:02:12Z

+def normalize_discarded_cards(state: State, action: Action, action_record=None):
+    if action.value is not None:
+        if isinstance(action.value, (list, tuple)):
+            return list(action.value)
+        return [action.value]
+
+    if action_record is not None and action_record.result is not None:
+        if isinstance(action_record.result, (list, tuple)):
+            return list(action_record.result)
+        return [action_record.result]
+
    hand = player_deck_to_array(state, action.color)
-    num_to_discard = len(hand) // 2
-    if action_record is None:
-        # TODO: Forcefully discard randomly so that decision tree doesnt explode in possibilities.
-        discarded = random.sample(hand, k=num_to_discard)
-    else:
-        discarded = action_record.result  # for replay functionality
+    return [random.choice(hand)]


What's the purpose of this function? Not following. Can we simplify and have the .value of DISCARD_RESOURCE be a resource and that's it? Not a list.

Also, why would we have to random.choice(hand) here? I think with this solution of discarding one at a time, we wouldn't need to random choose here, no?

bcollazo · 2026-03-25T22:05:00Z

+        if isinstance(value, list):
+            if len(value) != 1:
+                raise ValueError(
+                    "Discard action must have 1 resource when encoded as a list"
+                )
+            value = value[0]


Same here. Sounds like simplifying the .value to always a resource would simplify this code too!

bcollazo · 2026-03-25T22:05:44Z

+            self.discard_counts: Dict[Color, int] = {color: 0 for color in self.colors}
+            self.discard_counts: Dict[Color, int] = {color: 0 for color in self.colors}


Am I seeing double? hehe

bcollazo · 2026-03-25T22:06:01Z

+def test_discard_possibilities_are_per_resource():
+    player = SimplePlayer(Color.RED)
+    state = State([player])
+    state.discard_counts[player.color] = 2
+
+    player_deck_replenish(state, player.color, WHEAT, 2)
+    player_deck_replenish(state, player.color, BRICK, 1)
+
+    assert discard_possibilities(state, player.color) == [
+        Action(player.color, ActionType.DISCARD_RESOURCE, BRICK),
+        Action(player.color, ActionType.DISCARD_RESOURCE, WHEAT),
+    ]


Thank you! Can you add a couple more tests of this nature?

bcollazo · 2026-03-25T22:08:41Z

 } from "./api.types";
 import type { GameState } from "./api.types";

+export function humanizeAction(gameState: GameState, action: GameAction) {


Hmm.. we shouldn't need this function. Everything in the log should be ActionRecords.

bcollazo · 2026-03-25T22:10:07Z

Ahh, finally the checks were able to run. I think it may have been a transient error on Github's part? Anyways, let me know if you have any questions about CI checks and how to make them all green. 👍

Deterministic Discards

coveralls · 2026-03-31T02:07:35Z

Pull Request Test Coverage Report for Build 23776692959

Details

42 of 42 (100.0%) changed or added relevant lines in 5 files are covered.
1 unchanged line in 1 file lost coverage.
Overall coverage increased (+0.08%) to 93.98%

Files with Coverage Reduction	New Missed Lines	%
catanatron/catanatron/players/tree_search_utils.py	1	94.59%

Totals
Change from base Build 23773265000:	0.08%
Covered Lines:	3294
Relevant Lines:	3505

💛 - Coveralls

bcollazo · 2026-03-31T02:08:09Z

Awesome. Thank you so much for taking on this work! Makes it a lot more usable and representative. 👍

SY3141 force-pushed the Deterministic_Discards branch 4 times, most recently from d6c285f to 1284789 Compare March 21, 2026 04:26

Deterministic Discards

9ee99a7

SY3141 force-pushed the Deterministic_Discards branch from ba3b429 to 9ee99a7 Compare March 21, 2026 04:40

bcollazo reviewed Mar 22, 2026

View reviewed changes

SY3141 added 2 commits March 22, 2026 20:32

Merge remote-tracking branch 'upstream/main' into Deterministic_Discards

99657b3

Deterministic Discards and discard UI

68722f0

SY3141 force-pushed the Deterministic_Discards branch from 69f97b0 to 68722f0 Compare March 23, 2026 03:14

SY3141 changed the base branch from master to main March 25, 2026 17:56

bcollazo requested changes Mar 25, 2026

View reviewed changes

SY3141 and others added 7 commits March 26, 2026 23:10

simplified discard handling and removed some backcompatibility glue

b56b0af

Simplify DISCARD_RESOURCE value to a single Resource

7d2dea3

Update UI to use ActionRecords only

4a789c5

Merge branch 'main' into bryan/deterministic-discard

4786543

UI Nits

fafd04f

Improve apply_roll state.discard_counts setting

22ae9c4

Make FE Modal MultiDiscard

f4c899f

This was referenced Mar 31, 2026

Deterministic Discards #374

Closed

Deterministic Discards SY3141/catanatron#1

Merged

Merge pull request #1 from bcollazo/bryan/deterministic-discard

d0f47b1

Deterministic Discards

bcollazo merged commit 41ba0db into bcollazo:main Mar 31, 2026
11 checks passed

jeremiahjthomas mentioned this pull request Mar 31, 2026

Discarded resources can't be chosen #361

Closed

		assert action.value == (SHEEP,)


		def test_action_from_json_discard():

		self.discard_counts: Dict[Color, int] = {color: 0 for color in self.colors}
		self.discard_counts: Dict[Color, int] = {color: 0 for color in self.colors}

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SY3141 commented Mar 20, 2026

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bcollazo commented Mar 25, 2026

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