From edfbdf98cd12960362859e924a2b60036047a990 Mon Sep 17 00:00:00 2001
From: Hariom Verma <hariom18599@gmail.com>
Date: Thu, 2 May 2024 20:52:03 +0530
Subject: [PATCH] feat!: forbid importing '/r' from '/p'

---
 tm2/pkg/std/memfile.go      | 20 ++++++++
 tm2/pkg/std/memfile_test.go | 92 +++++++++++++++++++++++++++++++++----
 2 files changed, 103 insertions(+), 9 deletions(-)

diff --git a/tm2/pkg/std/memfile.go b/tm2/pkg/std/memfile.go
index 5655876c9bb..556bad02f07 100644
--- a/tm2/pkg/std/memfile.go
+++ b/tm2/pkg/std/memfile.go
@@ -2,6 +2,8 @@ package std
 
 import (
 	"fmt"
+	"go/parser"
+	"go/token"
 	"regexp"
 	"sort"
 	"strings"
@@ -80,6 +82,24 @@ func (mempkg *MemPackage) Validate() error {
 		prev = file.Name
 	}
 
+	// Check if package imports realm
+	// TODO(hariom): move this to a separate helper
+	if strings.HasPrefix(mempkg.Path, "gno.land/p") { // TODO(hariom): Use !gnolang.IsRealmPath() instead
+		for _, file := range mempkg.Files {
+			fset := token.NewFileSet()
+			astFile, err := parser.ParseFile(fset, file.Name, file.Body, parser.ImportsOnly)
+			if err != nil {
+				return fmt.Errorf("unable to parse %q", file.Name)
+			}
+			for _, imp := range astFile.Imports {
+				importPath := strings.TrimPrefix(strings.TrimSuffix(imp.Path.Value, `"`), `"`)
+				if strings.HasPrefix(importPath, "gno.land/r") { // TODO(hariom): Use gnolang.IsRealmPath() instead
+					return fmt.Errorf("package %q imports realm %q", mempkg.Path, importPath)
+				}
+			}
+		}
+	}
+
 	return nil
 }
 
diff --git a/tm2/pkg/std/memfile_test.go b/tm2/pkg/std/memfile_test.go
index 375e0d1a41a..abbe5dd1c27 100644
--- a/tm2/pkg/std/memfile_test.go
+++ b/tm2/pkg/std/memfile_test.go
@@ -15,30 +15,104 @@ func TestMemPackage_Validate(t *testing.T) {
 		{
 			"Correct",
 			&MemPackage{
-				Name:  "hey",
-				Path:  "gno.land/r/demo/hey",
-				Files: []*MemFile{{Name: "a.gno"}},
+				Name: "hey",
+				Path: "gno.land/r/demo/hey",
+				Files: []*MemFile{
+					{
+						Name: "a.gno",
+						Body: "package hey",
+					},
+				},
 			},
 			"",
 		},
 		{
 			"Unsorted",
 			&MemPackage{
-				Name:  "hey",
-				Path:  "gno.land/r/demo/hey",
-				Files: []*MemFile{{Name: "b.gno"}, {Name: "a.gno"}},
+				Name: "hey",
+				Path: "gno.land/r/demo/hey",
+				Files: []*MemFile{
+					{
+						Name: "b.gno",
+						Body: "package hey",
+					},
+					{
+						Name: "a.gno",
+						Body: "package hey",
+					},
+				},
 			},
 			`mempackage "gno.land/r/demo/hey" has unsorted files`,
 		},
 		{
 			"Duplicate",
 			&MemPackage{
-				Name:  "hey",
-				Path:  "gno.land/r/demo/hey",
-				Files: []*MemFile{{Name: "a.gno"}, {Name: "a.gno"}},
+				Name: "hey",
+				Path: "gno.land/r/demo/hey",
+				Files: []*MemFile{
+					{
+						Name: "a.gno",
+						Body: "package hey",
+					},
+					{
+						Name: "a.gno",
+						Body: "package hey",
+					},
+				},
 			},
 			`duplicate file name "a.gno"`,
 		},
+		{
+			"Package Imports Package",
+			&MemPackage{
+				Name: "hey",
+				Path: "gno.land/p/demo/hey",
+				Files: []*MemFile{
+					{
+						Name: "a.gno",
+						Body: `package hey
+
+						import "gno.land/p/demo/hello"
+						`,
+					},
+				},
+			},
+			"",
+		},
+		{
+			"Realm Imports Realm",
+			&MemPackage{
+				Name: "hey",
+				Path: "gno.land/r/demo/hey",
+				Files: []*MemFile{
+					{
+						Name: "a.gno",
+						Body: `package hey
+
+						import "gno.land/r/demo/hello"
+						`,
+					},
+				},
+			},
+			"",
+		},
+		{
+			"Package Imports Realm",
+			&MemPackage{
+				Name: "hey",
+				Path: "gno.land/p/demo/hey",
+				Files: []*MemFile{
+					{
+						Name: "a.gno",
+						Body: `package hey
+
+						import "gno.land/r/demo/heyrealm"
+						`,
+					},
+				},
+			},
+			`package "gno.land/p/demo/hey" imports realm "gno.land/r/demo/heyrealm"`,
+		},
 	}
 	for _, tc := range tt {
 		t.Run(tc.name, func(t *testing.T) {