Add minifier failure message

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "third_party/dawn"]
 	path = third_party/dawn
 	url = https://dawn.googlesource.com/dawn
+[submodule "third_party/range-v3"]
+	path = third_party/range-v3
+	url = https://github.com/ericniebler/range-v3.git

.vscode/settings.json

@@ -1,3 +1,4 @@
 {
-  "cmake.buildDirectory": "${workspaceFolder}/out/${buildType}"
+  "cmake.buildDirectory": "${workspaceFolder}/out/${buildType}",
+  "editor.formatOnSave": true
 }

minifier/CMakeLists.txt

@@ -1,6 +1,6 @@
 add_library(minifier src/minifier.cpp)
 target_include_directories(minifier PUBLIC include PRIVATE src)
-target_link_libraries(minifier PRIVATE tint_api)
+target_link_libraries(minifier PRIVATE tint_api range-v3)
 
 add_executable(minifier_test src/minifier_test.cpp)
 target_link_libraries(minifier_test PRIVATE minifier gtest_main)

minifier/include/minifier/minifier.h

@@ -9,7 +9,8 @@ struct Options {};
 
 struct Result {
     std::string wgsl;
-    bool failed;
+    std::string failureMessage;
+    bool failed = false;
 };
 
 Result Minify(std::string_view data, const Options& options);

minifier/src/minifier.cpp

@@ -1,11 +1,27 @@
 #include "minifier/minifier.h"
 
-#include "tint/tint.h"
+#include <src/tint/lang/wgsl/reader/reader.h>
+#include <src/tint/lang/wgsl/writer/writer.h>
+#include <src/tint/utils/diagnostic/diagnostic.h>
+
+#include <range/v3/all.hpp>
 
 namespace wgslx::minifier {
 
 static constexpr const auto* DefaultPath = "temp.wgsl";
 
+static Result GenerateError(const tint::diag::List& diagnostics) {
+    auto message = diagnostics | ranges::views::filter([](const tint::diag::Diagnostic& d) {
+                       return d.severity == tint::diag::Severity::Error;
+                   }) |
+                   ranges::views::transform([](const tint::diag::Diagnostic& d) { return d.message.Plain(); }) |
+                   ranges::views::join('\n') | ranges::to<std::string>();
+    return {
+        .failed = true,
+        .failureMessage = std::move(message),
+    };
+}
+
 Result Minify(std::string_view data, const Options& options) {
     tint::Source::File file(DefaultPath, data);
     auto program = tint::wgsl::reader::Parse(
@@ -15,15 +31,17 @@ Result Minify(std::string_view data, const Options& options) {
             .mode = tint::wgsl::ValidationMode::kFull,
         }
     );
+    if (program.Diagnostics().ContainsErrors()) {
+        return GenerateError(program.Diagnostics());
+    }
 
     auto result = tint::wgsl::writer::Generate(program, {});
     if (result != tint::Success) {
-        return {.failed = true};
+        return GenerateError(result.Failure().reason);
     }
 
     return {
         .wgsl = result->wgsl,
-        .failed = false,
     };
 }
 

minifier/src/minifier_test.cpp

@@ -17,4 +17,17 @@ fn average(a: f32, b: f32) -> f32 {
     EXPECT_EQ(result.wgsl, "fn average(a : f32, b : f32) -> f32 {\n  return ((a + b) / 2);\n}\n");
 }
 
+TEST(minifier, MinifyFailed) {
+    auto result = Minify(
+        R"(
+fn average(a: f32, b: f3) -> f32 {
+    return (a + b) / 2
+}
+)",
+        {}
+    );
+    EXPECT_TRUE(result.failed);
+    EXPECT_EQ(result.failureMessage, "expected ';' for return statement");
+}
+
 }  // namespace wgslx::minifier

third_party/CMakeLists.txt

@@ -25,3 +25,5 @@ set(TINT_BUILD_TESTS OFF)
 add_subdirectory(dawn)
 
 add_subdirectory(dawn/third_party/googletest)
+
+add_subdirectory(range-v3)