feat(stdlibs/std): restrict Banker methods based on caller of GetBank…

…er (gnolang#1921)

related pr gnolang#1787

There was bit of extra conversion in previous pr after merged. 
1) revert test cases
2) allow `Send` from realm that created banker rather the one calling

<!-- please provide a detailed description of the changes made in this
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<details><summary>Contributors' checklist...</summary>

- [x] Added new tests, or not needed, or not feasible
- [x] Provided an example (e.g. screenshot) to aid review or the PR is
self-explanatory
- [x] Updated the official documentation or not needed
- [x] No breaking changes were made, or a `BREAKING CHANGE: xxx` message
was included in the description
- [x] Added references to related issues and PRs
- [ ] Provided any useful hints for running manual tests
- [ ] Added new benchmarks to [generated
graphs](https://gnoland.github.io/benchmarks), if any. More info
[here](https://github.com/gnolang/gno/blob/master/.benchmarks/README.md).
</details>

---------

Co-authored-by: Morgan <git@howl.moe>

docs/concepts/stdlibs/coin.md

@@ -32,4 +32,4 @@ which can manipulate them depending on access rights.
 
 Read more about coins in the [Effective Gno](../effective-gno.md#coins) section. 
 
-The Coin(s) API can be found in under the `std` package [reference](../../reference/stdlibs/std/coin.md).
+The Coin(s) API can be found in under the `std` package [reference](../../reference/stdlibs/std/coin.md).

examples/gno.land/r/demo/banktest/banktest.gno

@@ -40,7 +40,7 @@ func Deposit(returnDenom string, returnAmount int64) string {
 	// return if any.
 	if returnAmount > 0 {
 		banker := std.GetBanker(std.BankerTypeOrigSend)
-		pkgaddr := std.CurrentRealm().Addr()
+		pkgaddr := std.GetOrigPkgAddr()
 		// TODO: use std.Coins constructors, this isn't generally safe.
 		banker.SendCoins(pkgaddr, caller, send)
 		return "returned!"

examples/gno.land/r/demo/banktest/z_0_filetest.gno

@@ -1,47 +1,48 @@
-package main
-
-// NOTE: this doesn't do anything, as it sends to "main".
 // SEND: 100000000ugnot
 
+package main
+
 import (
 	"std"
 
 	"gno.land/r/demo/banktest"
 )
 
 func main() {
+	// set up main address and banktest addr.
 	banktestAddr := std.DerivePkgAddr("gno.land/r/demo/banktest")
-
-	// print main balance before.
 	mainaddr := std.DerivePkgAddr("main")
 	std.TestSetOrigCaller(mainaddr)
+	std.TestSetOrigPkgAddr(banktestAddr)
 
-	banker := std.GetBanker(std.BankerTypeReadonly)
+	// get and print balance of mainaddr.
+	// with the SEND, + 200 gnot given by the TestContext, main should have 300gnot.
+	banker := std.GetBanker(std.BankerTypeRealmSend)
 	mainbal := banker.GetCoins(mainaddr)
-	println("main before:", mainbal) // plus OrigSend equals 300.
+	println("main before:", mainbal)
 
-	// simulate a Deposit call.
-	std.TestIssueCoins(banktestAddr, std.Coins{{"ugnot", 100000000}})
-	std.TestSetOrigSend(std.Coins{{"ugnot", 100000000}}, nil)
-	res := banktest.Deposit("ugnot", 100000000)
+	// simulate a Deposit call. use Send + OrigSend to simulate -send.
+	banker.SendCoins(mainaddr, banktestAddr, std.Coins{{"ugnot", 100_000_000}})
+	std.TestSetOrigSend(std.Coins{{"ugnot", 100_000_000}}, nil)
+	res := banktest.Deposit("ugnot", 50_000_000)
 	println("Deposit():", res)
 
 	// print main balance after.
 	mainbal = banker.GetCoins(mainaddr)
-	println("main after:", mainbal) // still 300.
+	println("main after:", mainbal)
 
-	// simulate a Render().
+	// simulate a Render(). banker should have given back all coins.
 	res = banktest.Render("")
 	println(res)
 }
 
 // Output:
-// main before: 200000000ugnot
+// main before: 300000000ugnot
 // Deposit(): returned!
-// main after: 300000000ugnot
+// main after: 250000000ugnot
 // ## recent activity
 //
-//  * g17rgsdnfxzza0sdfsdma37sdwxagsz378833ca4 100000000ugnot sent, 100000000ugnot returned, at 2009-02-13 11:31pm UTC
+//  * g17rgsdnfxzza0sdfsdma37sdwxagsz378833ca4 100000000ugnot sent, 50000000ugnot returned, at 2009-02-13 11:31pm UTC
 //
 // ## total deposits
-// 300000000ugnot
+// 50000000ugnot

examples/gno.land/r/demo/banktest/z_1_filetest.gno

@@ -10,6 +10,7 @@ func main() {
 	banktestAddr := std.DerivePkgAddr("gno.land/r/demo/banktest")
 
 	// simulate a Deposit call.
+	std.TestSetOrigPkgAddr(banktestAddr)
 	std.TestIssueCoins(banktestAddr, std.Coins{{"ugnot", 100000000}})
 	std.TestSetOrigSend(std.Coins{{"ugnot", 100000000}}, nil)
 	res := banktest.Deposit("ugnot", 101000000)

examples/gno.land/r/demo/banktest/z_3_filetest.gno

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"std"
+)
+
+func main() {
+	banktestAddr := std.DerivePkgAddr("gno.land/r/demo/banktest")
+
+	mainaddr := std.DerivePkgAddr("main")
+	std.TestSetOrigCaller(mainaddr)
+
+	banker := std.GetBanker(std.BankerTypeRealmSend)
+	send := std.Coins{{"ugnot", 123}}
+	banker.SendCoins(banktestAddr, mainaddr, send)
+
+}
+
+// Error:
+// can only send coins from realm that created banker "g17rgsdnfxzza0sdfsdma37sdwxagsz378833ca4", not "g1dv3435088tlrgggf745kaud0ptrkc9v42k8llz"

examples/gno.land/r/demo/wugnot/z0_filetest.gno

@@ -41,16 +41,10 @@ func printBalances() {
 	printSingleBalance := func(name string, addr std.Address) {
 		wugnotBal := wugnot.BalanceOf(pusers.AddressOrName(addr))
 		std.TestSetOrigCaller(addr)
-		abanker := std.GetBanker(std.BankerTypeOrigSend)
-		acoins := abanker.GetCoins(addr).AmountOf("ugnot")
-		bbanker := std.GetBanker(std.BankerTypeRealmIssue)
-		bcoins := bbanker.GetCoins(addr).AmountOf("ugnot")
-		cbanker := std.GetBanker(std.BankerTypeRealmSend)
-		ccoins := cbanker.GetCoins(addr).AmountOf("ugnot")
-		dbanker := std.GetBanker(std.BankerTypeReadonly)
-		dcoins := dbanker.GetCoins(addr).AmountOf("ugnot")
-		fmt.Printf("| %-13s | addr=%s | wugnot=%-5d | ugnot=%-9d %-9d %-9d %-9d |\n",
-			name, addr, wugnotBal, acoins, bcoins, ccoins, dcoins)
+		robanker := std.GetBanker(std.BankerTypeReadonly)
+		coins := robanker.GetCoins(addr).AmountOf("ugnot")
+		fmt.Printf("| %-13s | addr=%s | wugnot=%-5d | ugnot=%-9d |\n",
+			name, addr, wugnotBal, coins)
 	}
 	println("-----------")
 	printSingleBalance("wugnot_test", addrt)
@@ -61,17 +55,17 @@ func printBalances() {
 
 // Output:
 // -----------
-// | wugnot_test   | addr=g19rmydykafrqyyegc8uuaxxpzqwzcnxraj2dev9 | wugnot=0     | ugnot=200000000 200000000 200000000 200000000 |
-// | wugnot        | addr=g1pf6dv9fjk3rn0m4jjcne306ga4he3mzmupfjl6 | wugnot=0     | ugnot=100000001 100000001 100000001 100000001 |
-// | addr1         | addr=g1w3jhxap3ta047h6lta047h6lta047h6l4mfnm7 | wugnot=0     | ugnot=100000001 100000001 100000001 100000001 |
+// | wugnot_test   | addr=g19rmydykafrqyyegc8uuaxxpzqwzcnxraj2dev9 | wugnot=0     | ugnot=200000000 |
+// | wugnot        | addr=g1pf6dv9fjk3rn0m4jjcne306ga4he3mzmupfjl6 | wugnot=0     | ugnot=100000001 |
+// | addr1         | addr=g1w3jhxap3ta047h6lta047h6lta047h6l4mfnm7 | wugnot=0     | ugnot=100000001 |
 // -----------
 // -----------
-// | wugnot_test   | addr=g19rmydykafrqyyegc8uuaxxpzqwzcnxraj2dev9 | wugnot=123400 | ugnot=200000000 200000000 200000000 200000000 |
-// | wugnot        | addr=g1pf6dv9fjk3rn0m4jjcne306ga4he3mzmupfjl6 | wugnot=0     | ugnot=100000001 100000001 100000001 100000001 |
-// | addr1         | addr=g1w3jhxap3ta047h6lta047h6lta047h6l4mfnm7 | wugnot=0     | ugnot=100000001 100000001 100000001 100000001 |
+// | wugnot_test   | addr=g19rmydykafrqyyegc8uuaxxpzqwzcnxraj2dev9 | wugnot=123400 | ugnot=200000000 |
+// | wugnot        | addr=g1pf6dv9fjk3rn0m4jjcne306ga4he3mzmupfjl6 | wugnot=0     | ugnot=100000001 |
+// | addr1         | addr=g1w3jhxap3ta047h6lta047h6lta047h6l4mfnm7 | wugnot=0     | ugnot=100000001 |
 // -----------
 // -----------
-// | wugnot_test   | addr=g19rmydykafrqyyegc8uuaxxpzqwzcnxraj2dev9 | wugnot=119158 | ugnot=200004242 200004242 200004242 200004242 |
-// | wugnot        | addr=g1pf6dv9fjk3rn0m4jjcne306ga4he3mzmupfjl6 | wugnot=0     | ugnot=99995759  99995759  99995759  99995759  |
-// | addr1         | addr=g1w3jhxap3ta047h6lta047h6lta047h6l4mfnm7 | wugnot=0     | ugnot=100000001 100000001 100000001 100000001 |
+// | wugnot_test   | addr=g19rmydykafrqyyegc8uuaxxpzqwzcnxraj2dev9 | wugnot=119158 | ugnot=200004242 |
+// | wugnot        | addr=g1pf6dv9fjk3rn0m4jjcne306ga4he3mzmupfjl6 | wugnot=0     | ugnot=99995759  |
+// | addr1         | addr=g1w3jhxap3ta047h6lta047h6lta047h6l4mfnm7 | wugnot=0     | ugnot=100000001 |
 // -----------

gnovm/stdlibs/std/banker.gno

@@ -1,6 +1,8 @@
 package std
 
-import "strconv"
+import (
+	"strconv"
+)
 
 // Realm functions can call std.GetBanker(options) to get
 // a banker instance. Banker objects cannot be persisted,
@@ -66,7 +68,20 @@ func GetBanker(bt BankerType) Banker {
 	if bt >= maxBanker {
 		panic("invalid banker type")
 	}
-	return banker{bt}
+
+	var pkgAddr Address
+	if bt == BankerTypeOrigSend {
+		pkgAddr = GetOrigPkgAddr()
+		if pkgAddr != CurrentRealm().Addr() {
+			panic("banker with type BankerTypeOrigSend can only be instantiated by the origin package")
+		}
+	} else if bt == BankerTypeRealmSend || bt == BankerTypeRealmIssue {
+		pkgAddr = CurrentRealm().Addr()
+	}
+	return banker{
+		bt,
+		pkgAddr,
+	}
 }
 
 // These are native bindings to the banker's functions.
@@ -77,7 +92,8 @@ func bankerIssueCoin(bt uint8, addr string, denom string, amount int64)
 func bankerRemoveCoin(bt uint8, addr string, denom string, amount int64)
 
 type banker struct {
-	bt BankerType
+	bt      BankerType
+	pkgAddr Address
 }
 
 func (b banker) GetCoins(addr Address) (dst Coins) {
@@ -93,6 +109,10 @@ func (b banker) SendCoins(from, to Address, amt Coins) {
 	if b.bt == BankerTypeReadonly {
 		panic("BankerTypeReadonly cannot send coins")
 	}
+	if b.pkgAddr != from {
+		msg := `can only send coins from realm that created banker "` + b.pkgAddr + `", not "` + from + `"`
+		panic(msg)
+	}
 	denoms, amounts := amt.expandNative()
 	bankerSendCoins(uint8(b.bt), string(from), string(to), denoms, amounts)
 }

gnovm/stdlibs/std/banker.go

@@ -48,23 +48,6 @@ func X_bankerSendCoins(m *gno.Machine, bt uint8, fromS, toS string, denoms []str
 	amt := CompactCoins(denoms, amounts)
 	from, to := crypto.Bech32Address(fromS), crypto.Bech32Address(toS)
 
-	pkgAddr := ctx.OrigPkgAddr
-	if m.Realm != nil {
-		pkgPath := m.Realm.Path
-		pkgAddr = gno.DerivePkgAddr(pkgPath).Bech32()
-	}
-
-	if bt == btOrigSend || bt == btRealmSend {
-		if from != pkgAddr {
-			m.Panic(typedString(
-				fmt.Sprintf(
-					"can only send from the realm package address %q, but got %q",
-					pkgAddr, from),
-			))
-			return
-		}
-	}
-
 	switch bt {
 	case btOrigSend:
 		// indirection allows us to "commit" in a second phase