fix nil interface bug

stellar · Dec 14, 2020 · 6a61fad · 6a61fad
1 parent bf8a410
commit 6a61fad
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Showing 2 changed files with 13 additions and 5 deletions.
diff --git a/ingest/ledgerbackend/captive_core_backend.go b/ingest/ledgerbackend/captive_core_backend.go
@@ -192,9 +192,13 @@ func (c *CaptiveStellarCore) openOfflineReplaySubprocess(from, to uint32) error
 		to = latestCheckpointSequence
 	}
 
-	c.stellarCoreRunner, err = c.stellarCoreRunnerFactory(stellarCoreRunnerModeOffline)
-	if err != nil {
+	var runner stellarCoreRunnerInterface
+	if runner, err = c.stellarCoreRunnerFactory(stellarCoreRunnerModeOffline); err != nil {
 		return errors.Wrap(err, "error creating stellar-core runner")
+	} else {
+		// only assign c.stellarCoreRunner if runner is not nil to avoid nil interface check
+		// see https://golang.org/doc/faq#nil_error
+		c.stellarCoreRunner = runner
 	}
 
 	err = c.stellarCoreRunner.catchup(from, to)
@@ -231,9 +235,13 @@ func (c *CaptiveStellarCore) openOnlineReplaySubprocess(from uint32) error {
 		)
 	}
 
-	c.stellarCoreRunner, err = c.stellarCoreRunnerFactory(stellarCoreRunnerModeOnline)
-	if err != nil {
+	var runner stellarCoreRunnerInterface
+	if runner, err = c.stellarCoreRunnerFactory(stellarCoreRunnerModeOnline); err != nil {
 		return errors.Wrap(err, "error creating stellar-core runner")
+	} else {
+		// only assign c.stellarCoreRunner if runner is not nil to avoid nil interface check
+		// see https://golang.org/doc/faq#nil_error
+		c.stellarCoreRunner = runner
 	}
 
 	runFrom, ledgerHash, nextLedger, err := c.runFromParams(from)

diff --git a/ingest/ledgerbackend/captive_core_backend_test.go b/ingest/ledgerbackend/captive_core_backend_test.go
@@ -544,7 +544,7 @@ func TestGetLatestLedgerSequence(t *testing.T) {
 	err := captiveBackend.PrepareRange(UnboundedRange(64))
 	assert.NoError(t, err)
 
-	// To prevent flaky test runs handleExit for channel to fill.
+	// To prevent flaky test runs wait for channel to fill.
 	waitForBufferToFill(&captiveBackend)
 
 	latest, err := captiveBackend.GetLatestLedgerSequence()