Merge pull request #2835 from onflow/sainati/view-before

Check `before` statements in `view` contexts
onflow · Oct 3, 2023 · 445adf4 · 445adf4
2 parents 09fb4b8 + bf4207b
commit 445adf4
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Showing 3 changed files with 96 additions and 3 deletions.
diff --git a/runtime/sema/check_function.go b/runtime/sema/check_function.go
@@ -344,7 +344,10 @@ func (checker *Checker) visitWithPostConditions(postConditions *ast.Conditions,
 
 		checker.Elaboration.SetPostConditionsRewrite(postConditions, rewriteResult)
 
-		checker.visitStatements(rewriteResult.BeforeStatements)
+		// all condition blocks are `view`
+		checker.InNewPurityScope(true, func() {
+			checker.visitStatements(rewriteResult.BeforeStatements)
+		})
 	}
 
 	body()

diff --git a/runtime/tests/checker/conditions_test.go b/runtime/tests/checker/conditions_test.go
@@ -1018,3 +1018,92 @@ func TestCheckRewrittenPostConditions(t *testing.T) {
 
 	})
 }
+
+func TestCheckBeforeConditions(t *testing.T) {
+
+	t.Parallel()
+
+	t.Run("function call", func(t *testing.T) {
+
+		t.Parallel()
+
+		_, err := ParseAndCheck(t, `
+      fun impure(): Int { 
+        return 0
+      }
+
+      fun test() {
+          post {
+            before(impure()) > 0
+          }
+      }
+    `)
+
+		errs := RequireCheckerErrors(t, err, 1)
+
+		assert.IsType(t, &sema.PurityError{}, errs[0])
+	})
+
+	t.Run("view function call", func(t *testing.T) {
+
+		t.Parallel()
+
+		_, err := ParseAndCheck(t, `
+            view fun pure(): Int { 
+                return 0
+            }
+
+            fun test() {
+                post {
+                    before(pure()) > 0
+                }
+            }
+        `)
+
+		require.NoError(t, err)
+	})
+
+	t.Run("nested function call", func(t *testing.T) {
+
+		t.Parallel()
+
+		_, err := ParseAndCheck(t, `
+            view fun pure(): Int { 
+                return 0
+            }
+
+            fun impure(): Int { 
+                return 0
+            }
+
+            fun test() {
+                post {
+                    before(before(impure())) > pure()
+                }
+            }
+        `)
+
+		errs := RequireCheckerErrors(t, err, 1)
+
+		assert.IsType(t, &sema.PurityError{}, errs[0])
+	})
+
+	t.Run("nested pure function call", func(t *testing.T) {
+
+		t.Parallel()
+
+		_, err := ParseAndCheck(t, `
+            view fun pure(): Int { 
+                return 0
+            }
+
+            fun test() {
+                post {
+                    before(before(pure())) > 0 
+                }
+            }
+        `)
+
+		require.NoError(t, err)
+	})
+}
diff --git a/runtime/tests/checker/resources_test.go b/runtime/tests/checker/resources_test.go
@@ -5673,9 +5673,10 @@ func TestCheckInvalidationInPostConditionBefore(t *testing.T) {
       }
     `)
 
-	errs := RequireCheckerErrors(t, err, 1)
+	errs := RequireCheckerErrors(t, err, 2)
 
-	assert.IsType(t, &sema.ResourceUseAfterInvalidationError{}, errs[0])
+	assert.IsType(t, &sema.PurityError{}, errs[0])
+	assert.IsType(t, &sema.ResourceUseAfterInvalidationError{}, errs[1])
 }
 
 func TestCheckInvalidationInPostCondition(t *testing.T) {