6 files changed, 63 insertions(+), 17 deletions(-)

M lib/dhall/ast.rb
M lib/dhall/binary.rb
M lib/dhall/resolve.rb
M test/normalization/gen
M test/test_resolve.rb
M test/test_resolvers.rb

@@ 974,10 974,28 @@ module Dhall
 		end
 
 		class IntegrityCheck
-			def initialize(protocol, data)
+			class FailureException < StandardError; end
+
+			def initialize(protocol=:nocheck, data=nil)
 				@protocol = protocol
 				@data = data
 			end
+
+			def to_s
+				"#{@protocol}:#{@data}"
+			end
+
+			def check(expr)
+				if @protocol == :nocheck || expr.cache_key == to_s
+					expr
+				else
+					raise FailureException, "#{expr} does not match #{self}"
+				end
+			end
+
+			def as_json
+				@protocol == :nocheck ? nil : [@protocol, @data]
+			end
 		end
 
 		class Expression

@@ 1,6 1,7 @@
 # frozen_string_literal: true
 
 require "cbor"
+require "digest/sha2"
 
 require "dhall/ast"
 require "dhall/builtins"


@@ 33,6 34,14 @@ module Dhall
 		def as_cbor
 			as_json
 		end
+
+		def digest(digest: Digest::SHA2.new(256))
+			(digest << normalize.to_binary).freeze
+		end
+
+		def cache_key
+			"sha256:#{digest.hexdigest}"
+		end
 	end
 
 	class Application


@@ 180,7 189,7 @@ module Dhall
 			parts[0] = Dhall.decode(parts[0]) if path_type < 2 && !parts[0].nil?
 
 			new(
-				integrity_check.nil? ? nil : IntegrityCheck.new(*integrity_check),
+				IntegrityCheck.new(*integrity_check),
 				IMPORT_TYPES[import_type],
 				PATH_TYPES[path_type].new(*parts)
 			)

@@ 246,8 246,10 @@ module Dhall
 
 			def resolve(resolver)
 				@expr.instance_eval do
-					@path.resolve(resolver).then do |expr|
-						@import_type.call(expr).resolve(resolver.child(@path))
+					@path.resolve(resolver).then do |result|
+						@integrity_check.check(
+							@import_type.call(result)
+						).resolve(resolver.child(@path))
 					end
 				end
 			end

@@ 1,5 1,9 @@
 #!/bin/sh
 
 cp -r "$(git root)"/dhall-lang/tests/normalization/success "$(git root)"/test/normalization/standard
+
 cd "$(git root)"/test/normalization/standard
 find . -name '*.dhall' -exec "$(git root)"/test/normalization/dhall-encode '{}' \;
+
+cd "$(git root)"/test/normalization
+find . -name '*.dhallb' -exec "$(git root)"/test/normalization/dhall-hash '{}' \;

@@ 44,7 44,7 @@ class TestResolve < Minitest::Test
 
 	def test_import_as_text
 		expr = Dhall::Import.new(
-			nil,
+			Dhall::Import::IntegrityCheck.new,
 			Dhall::Import::Text,
 			Dhall::Import::RelativePath.new("text")
 		)


@@ 59,7 59,7 @@ class TestResolve < Minitest::Test
 		expr = Dhall::Function.of_arguments(
 			Dhall::Variable["Natural"],
 			body: Dhall::Import.new(
-				nil,
+				Dhall::Import::IntegrityCheck.new,
 				Dhall::Import::Expression,
 				Dhall::Import::RelativePath.new("var")
 			)


@@ 75,7 75,7 @@ class TestResolve < Minitest::Test
 		expr = Dhall::Function.of_arguments(
 			Dhall::Variable["Natural"],
 			body: Dhall::Import.new(
-				nil,
+				Dhall::Import::IntegrityCheck.new,
 				Dhall::Import::Expression,
 				Dhall::Import::RelativePath.new("import")
 			)


@@ 91,7 91,7 @@ class TestResolve < Minitest::Test
 		expr = Dhall::Function.of_arguments(
 			Dhall::Variable["Natural"],
 			body: Dhall::Import.new(
-				nil,
+				Dhall::Import::IntegrityCheck.new,
 				Dhall::Import::Expression,
 				Dhall::Import::RelativePath.new("self")
 			)


@@ 106,7 106,7 @@ class TestResolve < Minitest::Test
 		expr = Dhall::Function.of_arguments(
 			Dhall::Variable["Natural"],
 			body: Dhall::Import.new(
-				nil,
+				Dhall::Import::IntegrityCheck.new,
 				Dhall::Import::Expression,
 				Dhall::Import::RelativePath.new("a")
 			)


@@ 119,7 119,7 @@ class TestResolve < Minitest::Test
 
 	def test_two_references_no_loop
 		expr = Dhall::Import.new(
-			nil,
+			Dhall::Import::IntegrityCheck.new,
 			Dhall::Import::Expression,
 			Dhall::Import::RelativePath.new("2text")
 		)


@@ 135,7 135,7 @@ class TestResolve < Minitest::Test
 
 	def test_missing
 		expr = Dhall::Import.new(
-			nil,
+			Dhall::Import::IntegrityCheck.new,
 			Dhall::Import::Expression,
 			Dhall::Import::MissingImport.new
 		)


@@ 145,10 145,22 @@ class TestResolve < Minitest::Test
 		end
 	end
 
+	def test_integrity_check_failure
+		expr = Dhall::Import.new(
+			Dhall::Import::IntegrityCheck.new("sha256", "badhash"),
+			Dhall::Import::Expression,
+			Dhall::Import::RelativePath.new("var")
+		)
+
+		assert_raises Dhall::Import::IntegrityCheck::FailureException do
+			expr.resolve(@resolver).sync
+		end
+	end
+
 	def test_fallback_to_expr
 		expr = Dhall::Operator::ImportFallback.new(
 			lhs: Dhall::Import.new(
-				nil,
+				Dhall::Import::IntegrityCheck.new,
 				Dhall::Import::Expression,
 				Dhall::Import::MissingImport.new
 			),


@@ 161,12 173,12 @@ class TestResolve < Minitest::Test
 	def test_fallback_to_import
 		expr = Dhall::Operator::ImportFallback.new(
 			lhs: Dhall::Import.new(
-				nil,
+				Dhall::Import::IntegrityCheck.new,
 				Dhall::Import::Expression,
 				Dhall::Import::MissingImport.new
 			),
 			rhs: Dhall::Import.new(
-				nil,
+				Dhall::Import::IntegrityCheck.new,
 				Dhall::Import::Expression,
 				Dhall::Import::RelativePath.new("import")
 			)


@@ 181,7 193,7 @@ class TestResolve < Minitest::Test
 			.to_return(status: 200, body: "\x00")
 
 		expr = Dhall::Import.new(
-			nil,
+			Dhall::Import::IntegrityCheck.new,
 			Dhall::Import::Expression,
 			Dhall::Import::RelativePath.new("using")
 		)


@@ 194,7 206,7 @@ class TestResolve < Minitest::Test
 			.to_return(status: 200, body: "\x00")
 
 		expr = Dhall::Import.new(
-			nil,
+			Dhall::Import::IntegrityCheck.new,
 			Dhall::Import::Expression,
 			Dhall::Import::AbsolutePath.new("ipfs", "TESTCID")
 		)


@@ 210,7 222,7 @@ class TestResolve < Minitest::Test
 			.to_return(status: 200, body: "\x00")
 
 		expr = Dhall::Import.new(
-			nil,
+			Dhall::Import::IntegrityCheck.new,
 			Dhall::Import::Expression,
 			Dhall::Import::AbsolutePath.new("ipfs", "TESTCID")
 		)

@@ 3,6 3,7 @@
 require "minitest/autorun"
 
 require "dhall/resolve"
+require "dhall/normalize"
 
 class TestResolvers < Minitest::Test
 	def test_default_resolver_path