Fixup negative citation propagations to handle all cases

forum-network/src/classes/forum.js

@@ -100,8 +100,12 @@ export class Forum extends ReputationHolder {
 
     // Apply computed rewards to update values of tokens
     for (const [id, value] of rewardsAccumulator) {
+      if (value < 0) {
+        bench.reputation.transferValueFrom(id, post.tokenId, -value);
+      } else {
         bench.reputation.transferValueFrom(post.tokenId, id, value);
       }
+    }
 
     // Transfer ownership of the minted/staked token, from the forum to the post author
     bench.reputation.transferFrom(this.id, post.authorPublicKey, post.tokenId);
@@ -126,18 +130,31 @@ export class Forum extends ReputationHolder {
           const citedPostCapacity = citedPost.value / (1 - citedPostTotalCitationWeight);
           outboundAmount = Math.max(outboundAmount, -citedPostCapacity);
         }
-        totalOutboundAmount += outboundAmount;
-        await this.propagateValue(rewardsAccumulator, post, citedPost, outboundAmount, depth + 1);
+        const refundFromOutbound = await this.propagateValue(
+          rewardsAccumulator,
+          post,
+          citedPost,
+          outboundAmount,
+          depth + 1,
+        );
+        totalOutboundAmount += outboundAmount - refundFromOutbound;
       }
     }
 
     // Apply leaching value
     const incrementAfterLeaching = increment - totalOutboundAmount * params.leachingValue;
 
+    const rawNewValue = post.value + incrementAfterLeaching;
+    const newValue = Math.max(0, rawNewValue);
+    const appliedIncrement = newValue - post.value;
+    const refundToInbound = increment - appliedIncrement;
+
     // Award reputation to post author
-    rewardsAccumulator.set(post.tokenId, incrementAfterLeaching);
+    rewardsAccumulator.set(post.tokenId, appliedIncrement);
 
     // Increment the value of the post
-    await this.setPostValue(post, post.value + incrementAfterLeaching);
+    await this.setPostValue(post, newValue);
+
+    return refundToInbound;
   }
 }

forum-network/src/classes/reputation-token.js

@@ -45,16 +45,17 @@ export class ReputationTokenContract extends ERC721 {
     if (amount === undefined) {
       throw new Error('Transfer value: amount is undefined!');
     }
+    if (amount === 0) {
+      return;
+    }
+    if (amount < 0) {
+      throw new Error('Transfer value: amount must be positive');
+    }
     const sourceAvailable = this.availableValueOf(fromTokenId);
-    const targetAvailable = this.availableValueOf(toTokenId);
     if (sourceAvailable < amount - EPSILON) {
       throw new Error('Token value transfer: source has insufficient available value. '
       + `Needs ${amount}; has ${sourceAvailable}.`);
     }
-    if (targetAvailable < -amount + EPSILON) {
-      throw new Error('Token value transfer: target has insufficient available value. '
-      + `Needs ${-amount}; has ${targetAvailable}.`);
-    }
     this.incrementValue(fromTokenId, -amount);
     this.incrementValue(toTokenId, amount);
   }