Merge pull request #1293 from MetaMask/ImproveGasEstimates

tx-utils - gas buffer ceiling at 90% of block gas limit

2 files changed, 21 insertions, 14 deletions

diff --git a/app/scripts/lib/tx-utils.js b/app/scripts/lib/tx-utils.js
index 72df53631..e8e23f8b5 100644
--- a/app/scripts/lib/tx-utils.js
+++ b/app/scripts/lib/tx-utils.js
@@ -63,14 +63,15 @@ module.exports = class txProviderUtils {
   addGasBuffer (initialGasLimitHex, blockGasLimitHex) {
     const initialGasLimitBn = hexToBn(initialGasLimitHex)
     const blockGasLimitBn = hexToBn(blockGasLimitHex)
+    const upperGasLimitBn = blockGasLimitBn.muln(0.9)
     const bufferedGasLimitBn = initialGasLimitBn.muln(1.5)
 
     // if initialGasLimit is above blockGasLimit, dont modify it
-    if (initialGasLimitBn.gt(blockGasLimitBn)) return bnToHex(initialGasLimitBn)
+    if (initialGasLimitBn.gt(upperGasLimitBn)) return bnToHex(initialGasLimitBn)
     // if bufferedGasLimit is below blockGasLimit, use bufferedGasLimit
-    if (bufferedGasLimitBn.lt(blockGasLimitBn)) return bnToHex(bufferedGasLimitBn)
+    if (bufferedGasLimitBn.lt(upperGasLimitBn)) return bnToHex(bufferedGasLimitBn)
     // otherwise use blockGasLimit
-    return bnToHex(blockGasLimitBn)
+    return bnToHex(upperGasLimitBn)
   }
 
   fillInTxParams (txParams, cb) {
diff --git a/test/unit/tx-utils-test.js b/test/unit/tx-utils-test.js
index e57b25e83..8b4d2f059 100644
--- a/test/unit/tx-utils-test.js
+++ b/test/unit/tx-utils-test.js
@@ -14,8 +14,8 @@ describe('txUtils', function() {
 
   describe('addGasBuffer', function() {
     it('multiplies by 1.5, when within block gas limit', function() {
-      // naive estimatedGas: 0x123fad (~1.2 mil)
-      const inputHex = '0x123fad'
+      // naive estimatedGas: 0x16e360 (1.5 mil)
+      const inputHex = '0x16e360'
       // dummy gas limit: 0x3d4c52 (4 mil)
       const blockGasLimitHex = '0x3d4c52'
       const output = txUtils.addGasBuffer(inputHex, blockGasLimitHex)
@@ -26,8 +26,8 @@ describe('txUtils', function() {
     })
     
     it('uses original estimatedGas, when above block gas limit', function() {
-      // naive estimatedGas: 0x123fad (~1.2 mil)
-      const inputHex = '0x123fad'
+      // naive estimatedGas: 0x16e360 (1.5 mil)
+      const inputHex = '0x16e360'
       // dummy gas limit: 0x0f4240 (1 mil)
       const blockGasLimitHex = '0x0f4240'
       const output = txUtils.addGasBuffer(inputHex, blockGasLimitHex)
@@ -37,16 +37,18 @@ describe('txUtils', function() {
       assert(outputBn.eq(expectedBn), 'returns the original estimatedGas value')
     })
 
-    it('buffers up to block gas limit', function() {
-      // naive estimatedGas: 0x123fad (~1.2 mil)
-      const inputHex = '0x1e8480'
+    it('buffers up to reccomend gas limit reccomended ceiling', function() {
+      // naive estimatedGas: 0x16e360 (1.5 mil)
+      const inputHex = '0x16e360'
       // dummy gas limit: 0x1e8480 (2 mil)
       const blockGasLimitHex = '0x1e8480'
+      const blockGasLimitBn = hexToBn(blockGasLimitHex)
+      const ceilGasLimitBn = blockGasLimitBn.muln(0.9)
       const output = txUtils.addGasBuffer(inputHex, blockGasLimitHex)
-      const inputBn = hexToBn(inputHex)
-      const outputBn = hexToBn(output)
-      const expectedBn = hexToBn(blockGasLimitHex)
-      assert(outputBn.eq(expectedBn), 'returns the block gas limit value')
+      // const inputBn = hexToBn(inputHex)
+      // const outputBn = hexToBn(output)
+      const expectedHex = bnToHex(ceilGasLimitBn)
+      assert.equal(output, expectedHex, 'returns the gas limit reccomended ceiling value')
     })
   })
 })
@@ -55,4 +57,8 @@ describe('txUtils', function() {
 
 function hexToBn(inputHex) {
   return new BN(ethUtil.stripHexPrefix(inputHex), 16)
+}
+
+function bnToHex(inputBn) {
+  return ethUtil.addHexPrefix(inputBn.toString(16))
 }
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