fix(gno.land): refine error message for addpkg operation (#2409)

This PR introduces `PkgExistError` to replace `InvalidPkgPathError` for
situations where a package already exists during the `addpkg` operation,
enhancing clarity and specificity.

gno.land/pkg/sdk/vm/errors.go

@@ -16,6 +16,7 @@ func (abciError) AssertABCIError() {}
 // NOTE: these are meant to be used in conjunction with pkgs/errors.
 type (
 	InvalidPkgPathError   struct{ abciError }
+	PkgExistError         struct{ abciError }
 	InvalidStmtError      struct{ abciError }
 	InvalidExprError      struct{ abciError }
 	UnauthorizedUserError struct{ abciError }
@@ -26,6 +27,7 @@ type (
 )
 
 func (e InvalidPkgPathError) Error() string   { return "invalid package path" }
+func (e PkgExistError) Error() string         { return "package already exists" }
 func (e InvalidStmtError) Error() string      { return "invalid statement" }
 func (e InvalidExprError) Error() string      { return "invalid expression" }
 func (e UnauthorizedUserError) Error() string { return "unauthorized user" }
@@ -36,6 +38,10 @@ func (e TypeCheckError) Error() string {
 	return bld.String()
 }
 
+func ErrPkgAlreadyExists(msg string) error {
+	return errors.Wrap(PkgExistError{}, msg)
+}
+
 func ErrUnauthorizedUser(msg string) error {
 	return errors.Wrap(UnauthorizedUserError{}, msg)
 }

gno.land/pkg/sdk/vm/keeper.go

@@ -325,7 +325,7 @@ func (vm *VMKeeper) AddPackage(ctx sdk.Context, msg MsgAddPackage) (err error) {
 		return ErrInvalidPkgPath(err.Error())
 	}
 	if pv := gnostore.GetPackage(pkgPath, false); pv != nil {
-		return ErrInvalidPkgPath("package already exists: " + pkgPath)
+		return ErrPkgAlreadyExists("package already exists: " + pkgPath)
 	}
 	if gno.ReGnoRunPath.MatchString(pkgPath) {
 		return ErrInvalidPkgPath("reserved package name: " + pkgPath)

gno.land/pkg/sdk/vm/keeper_test.go

@@ -54,7 +54,7 @@ func Echo() string {return "hello world"}`,
 	err = env.vmk.AddPackage(ctx, msg1)
 
 	assert.Error(t, err)
-	assert.True(t, errors.Is(err, InvalidPkgPathError{}))
+	assert.True(t, errors.Is(err, PkgExistError{}))
 
 	// added package is formatted
 	store := env.vmk.getGnoTransactionStore(ctx)

gno.land/pkg/sdk/vm/package.go

@@ -18,6 +18,7 @@ var Package = amino.RegisterPackage(amino.NewPackage(
 
 	// errors
 	InvalidPkgPathError{}, "InvalidPkgPathError",
+	PkgExistError{}, "PkgExistError",
 	InvalidStmtError{}, "InvalidStmtError",
 	InvalidExprError{}, "InvalidExprError",
 	TypeCheckError{}, "TypeCheckError",

gno.land/pkg/sdk/vm/vm.proto

@@ -30,6 +30,9 @@ message m_addpkg {
 message InvalidPkgPathError {
 }
 
+message PkgExistError {
+}
+
 message InvalidStmtError {
 }