From 2af1283c65b6c1c5d4cccfe938e87e43eccad72f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ra=C3=BAl=20Kripalani?= <raul@protocol.ai>
Date: Tue, 15 Dec 2020 17:44:56 +0000
Subject: [PATCH] tvx exec: flag to fallback to API blockstore.

---
 cmd/tvx/exec.go       | 18 ++++++++++++++++--
 cmd/tvx/main.go       |  2 +-
 conformance/runner.go | 32 +++++++++++++++++++++++++++-----
 3 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/cmd/tvx/exec.go b/cmd/tvx/exec.go
index 89ad23913..f1ef91315 100644
--- a/cmd/tvx/exec.go
+++ b/cmd/tvx/exec.go
@@ -16,7 +16,8 @@ import (
 )
 
 var execFlags struct {
-	file string
+	file               string
+	fallbackBlockstore bool
 }
 
 var execCmd = &cli.Command{
@@ -30,10 +31,23 @@ var execCmd = &cli.Command{
 			TakesFile:   true,
 			Destination: &execFlags.file,
 		},
+		&cli.BoolFlag{
+			Name:        "fallback-blockstore",
+			Usage:       "sets the full node API as a fallback blockstore; use this if you're transplanting vectors and get block not found errors",
+			Destination: &execFlags.fallbackBlockstore,
+		},
 	},
 }
 
-func runExecLotus(_ *cli.Context) error {
+func runExecLotus(c *cli.Context) error {
+	if execFlags.fallbackBlockstore {
+		if err := initialize(c); err != nil {
+			return fmt.Errorf("fallback blockstore was enabled, but could not resolve lotus API endpoint: %w", err)
+		}
+		defer destroy(c) //nolint:errcheck
+		conformance.FallbackBlockstoreGetter = FullAPI
+	}
+
 	if file := execFlags.file; file != "" {
 		// we have a single test vector supplied as a file.
 		file, err := os.Open(file)
diff --git a/cmd/tvx/main.go b/cmd/tvx/main.go
index 8de851ed5..8dae39958 100644
--- a/cmd/tvx/main.go
+++ b/cmd/tvx/main.go
@@ -102,7 +102,7 @@ func initialize(c *cli.Context) error {
 	// Make the API client.
 	var err error
 	if FullAPI, Closer, err = lcli.GetFullNodeAPI(c); err != nil {
-		err = fmt.Errorf("failed to locate Lotus node; ")
+		err = fmt.Errorf("failed to locate Lotus node; err: %w", err)
 	}
 	return err
 }
diff --git a/conformance/runner.go b/conformance/runner.go
index 7ca7ea2c5..6eff25274 100644
--- a/conformance/runner.go
+++ b/conformance/runner.go
@@ -14,6 +14,7 @@ import (
 	"github.com/fatih/color"
 	"github.com/filecoin-project/go-state-types/abi"
 	"github.com/filecoin-project/go-state-types/exitcode"
+	blocks "github.com/ipfs/go-block-format"
 	"github.com/ipfs/go-blockservice"
 	"github.com/ipfs/go-cid"
 	ds "github.com/ipfs/go-datastore"
@@ -29,6 +30,14 @@ import (
 	"github.com/filecoin-project/lotus/lib/blockstore"
 )
 
+// FallbackBlockstoreGetter is a fallback blockstore to use for resolving CIDs
+// unknown to the test vector. This is rarely used, usually only needed
+// when transplanting vectors across versions. This is an interface tighter
+// than ChainModuleAPI. It can be backed by a FullAPI client.
+var FallbackBlockstoreGetter interface {
+	ChainReadObj(context.Context, cid.Cid) ([]byte, error)
+}
+
 // ExecuteMessageVector executes a message-class test vector.
 func ExecuteMessageVector(r Reporter, vector *schema.TestVector, variant *schema.Variant) {
 	var (
@@ -38,7 +47,7 @@ func ExecuteMessageVector(r Reporter, vector *schema.TestVector, variant *schema
 	)
 
 	// Load the CAR into a new temporary Blockstore.
-	bs, err := LoadVectorCAR(vector.CAR)
+	bs, err := LoadBlockstore(vector.CAR)
 	if err != nil {
 		r.Fatalf("failed to load the vector CAR: %w", err)
 	}
@@ -95,7 +104,7 @@ func ExecuteTipsetVector(r Reporter, vector *schema.TestVector, variant *schema.
 	)
 
 	// Load the vector CAR into a new temporary Blockstore.
-	bs, err := LoadVectorCAR(vector.CAR)
+	bs, err := LoadBlockstore(vector.CAR)
 	if err != nil {
 		r.Fatalf("failed to load the vector CAR: %w", err)
 	}
@@ -117,7 +126,7 @@ func ExecuteTipsetVector(r Reporter, vector *schema.TestVector, variant *schema.
 			Rand:        NewReplayingRand(r, vector.Randomness),
 		})
 		if err != nil {
-			r.Fatalf("failed to apply tipset %d message: %s", i, err)
+			r.Fatalf("failed to apply tipset %d: %s", i, err)
 		}
 
 		for j, v := range ret.AppliedResults {
@@ -254,8 +263,8 @@ func writeStateToTempCAR(bs blockstore.Blockstore, roots ...cid.Cid) (string, er
 	return tmp.Name(), nil
 }
 
-func LoadVectorCAR(vectorCAR schema.Base64EncodedBytes) (blockstore.Blockstore, error) {
-	bs := blockstore.NewTemporary()
+func LoadBlockstore(vectorCAR schema.Base64EncodedBytes) (blockstore.Blockstore, error) {
+	bs := blockstore.Blockstore(blockstore.NewTemporary())
 
 	// Read the base64-encoded CAR from the vector, and inflate the gzip.
 	buf := bytes.NewReader(vectorCAR)
@@ -270,5 +279,18 @@ func LoadVectorCAR(vectorCAR schema.Base64EncodedBytes) (blockstore.Blockstore,
 	if err != nil {
 		return nil, fmt.Errorf("failed to load state tree car from test vector: %s", err)
 	}
+
+	if FallbackBlockstoreGetter != nil {
+		fbs := &blockstore.FallbackStore{Blockstore: bs}
+		fbs.SetFallback(func(ctx context.Context, c cid.Cid) (blocks.Block, error) {
+			b, err := FallbackBlockstoreGetter.ChainReadObj(ctx, c)
+			if err != nil {
+				return nil, err
+			}
+			return blocks.NewBlockWithCid(b, c)
+		})
+		bs = fbs
+	}
+
 	return bs, nil
 }