A test that triggers null pointer exception on 3rd level of external query

x/wasm/internal/keeper/keeper.go

@@ -3,8 +3,11 @@ package keeper
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 	"path/filepath"
 
+	xdebug "runtime/debug"
+
 	"github.com/cosmos/cosmos-sdk/x/staking"
 	"github.com/pkg/errors"
 
@@ -336,7 +339,13 @@ func (k Keeper) QuerySmart(ctx sdk.Context, contractAddr sdk.AccAddress, req []b
 	if err != nil {
 		return nil, err
 	}
+
 	// prepare querier
+	if nil == k.queryPlugins.Wasm {
+		fmt.Println("k.queryPlugins.Wasm is nil: \n" + string(xdebug.Stack()))
+	}
+
+	fmt.Printf("keeper.go/QuerySmart/k.queryPlugins: %v\n", k.queryPlugins)
 	querier := QueryHandler{
 		Ctx:     ctx,
 		Plugins: k.queryPlugins,

x/wasm/internal/keeper/keeper_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"testing"
@@ -869,3 +870,30 @@ func keyPubAddr() (crypto.PrivKey, crypto.PubKey, sdk.AccAddress) {
 	addr := sdk.AccAddress(pub.Address())
 	return key, pub, addr
 }
+
+func TestOOMKillsInfiniteQueryLoopEithan(t *testing.T) {
+	tempDir, err := ioutil.TempDir("", "wasm")
+	require.NoError(t, err)
+	ctx, keepers := CreateTestInput(t, false, tempDir, SupportedFeatures, nil, nil)
+	accKeeper, keeper := keepers.AccountKeeper, keepers.WasmKeeper
+
+	deposit := sdk.NewCoins(sdk.NewInt64Coin("denom", 100000))
+	walletA := createFakeFundedAccount(ctx, accKeeper, deposit.Add(deposit...))
+
+	wasmCode, err := ioutil.ReadFile("./testdata/test-contract/contract.wasm.gz")
+	require.NoError(t, err)
+
+	codeID, err := keeper.Create(ctx, walletA, wasmCode, "", "")
+	require.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	// init
+
+	contractAddress, _ := keeper.Instantiate(ctx, codeID, walletA, nil, []byte(`{"nop":{}}`), "some label", sdk.NewCoins(sdk.NewInt64Coin("denom", 0)))
+
+	// infinite external query loop
+
+	_, err = keeper.QuerySmart(ctx, contractAddress, []byte(fmt.Sprintf(`{"send_external_query_infinite_loop":{"to":"%s"}}`, contractAddress.String())))
+
+	require.Error(t, err)
+}

x/wasm/internal/keeper/testdata/test-contract/.gitignore

@@ -0,0 +1,12 @@
+# Build results
+/target
+
+# Text file backups
+**/*.rs.bk
+
+# macOS
+.DS_Store
+
+# IDEs
+*.iml
+.idea

x/wasm/internal/keeper/testdata/test-contract/Cargo.toml

@@ -0,0 +1,40 @@
+[package]
+name = "test-contract"
+version = "0.0.1"
+authors = ["Enigma <info@enigma.co>"]
+edition = "2018"
+description = "A Test contract intended to use in system tests for the Secret Netowrk"
+license = "MIT"
+exclude = [
+  # Those files are cosmwasm-opt artifacts. You might want to commit them for convenience but they should not be part of the source code publication.
+  "contract.wasm",
+  "hash.txt",
+]
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[profile.release]
+opt-level = 3
+debug = false
+rpath = false
+lto = true
+debug-assertions = false
+codegen-units = 1
+panic = 'abort'
+incremental = false
+overflow-checks = true
+
+[features]
+default = ["backtraces"]
+backtraces = ["cosmwasm-std/backtraces"]
+
+[dependencies]
+cosmwasm-std = { git = "https://github.com/CosmWasm/cosmwasm", tag = "v0.9.1" }
+schemars = "0.7"
+serde = { version = "1.0.114", default-features = false, features = [
+  "derive",
+  "alloc"
+] }
+# serde-json-wasm = "0.2.1"

x/wasm/internal/keeper/testdata/test-contract/Makefile

@@ -0,0 +1,8 @@
+all:
+	RUSTFLAGS='-C link-arg=-s' cargo build --release --target wasm32-unknown-unknown --locked
+	wasm-opt -Os ./target/wasm32-unknown-unknown/release/test_contract.wasm -o ./contract.wasm
+	cat contract.wasm | gzip -9 > ./contract.wasm.gz
+
+clean:
+	cargo clean
+	-rm -f ./contract.wasm ./contract.wasm.gz

x/wasm/internal/keeper/testdata/test-contract/README.md

@@ -0,0 +1 @@
+Just `make`. :rainbow: