Merge #11133: Document assumptions that are being made to avoid division by zero

55509f1 Document assumptions that are being made to avoid division by zero (practicalswift)

Pull request description:

  Document assumptions (via `assert(…)`:s) that are being made to avoid division by zero.

  Rationale:
  * Make it clear to human reviewers and non-human static analyzers that what might look like potential division by zero cases are written the way they are intentionally (these cases are currently flagged by various static analyzers).

Tree-SHA512: bbb67b1370afd8f39bda35f9e3a20f4325f017d94cc1bfac3b0d36c9f34c2d95a9efe11efe44db29fb4aadd25d8276d8f0e03c8806ac64f0d21d821912e13b8e

src/policy/fees.cpp

@@ -503,6 +503,7 @@ void TxConfirmStats::removeTx(unsigned int entryHeight, unsigned int nBestSeenHe
         }
     }
     if (!inBlock && (unsigned int)blocksAgo >= scale) { // Only counts as a failure if not confirmed for entire period
+        assert(scale != 0);
         unsigned int periodsAgo = blocksAgo / scale;
         for (size_t i = 0; i < periodsAgo && i < failAvg.size(); i++) {
             failAvg[i][bucketindex]++;