Make DEFAULT_BLOCK_UNPAID_ACTION_LIMIT zero.

fixes zcash#6899 (see that issue for rationale)

Signed-off-by: Daira-Emma Hopwood <[email protected]>

doc/release-notes.md

@@ -4,6 +4,17 @@ release-notes at release time)
 Notable changes
 ===============
 
+Mining
+------
+
+- The default setting of `-blockunpaidactionlimit` is now zero, which has
+  the effect of no longer allowing "unpaid actions" in [block production].
+  This adapts to current network conditions. If you have overridden this
+  setting as a miner, we recommend removing the override. This configuration
+  option may be removed entirely in a future release.
+
+[block production]: https://zips.z.cash/zip-0317#block-production
+
 Platform Support
 ----------------
 

src/zip317.h

@@ -21,7 +21,7 @@ static const size_t P2PKH_STANDARD_OUTPUT_SIZE = 34;
 // Constants for block template construction.
 static const int64_t WEIGHT_RATIO_SCALE = INT64_C(10000000000000000);
 static const int64_t WEIGHT_RATIO_CAP = 4;
-static const size_t DEFAULT_BLOCK_UNPAID_ACTION_LIMIT = 50;
+static const size_t DEFAULT_BLOCK_UNPAID_ACTION_LIMIT = 0;
 
 /// Limit on the number of unpaid actions a transaction can have to be accepted to the mempool.
 static const size_t DEFAULT_TX_UNPAID_ACTION_LIMIT = DEFAULT_BLOCK_UNPAID_ACTION_LIMIT;