improve concept constraint diagnostics

Author: GaspardKirira

src/errors/template/ConceptConstraintFailureRule.cpp

@@ -14,9 +14,13 @@
 #include <vix/cli/errors/template/ITemplateErrorRule.hpp>
 #include <vix/cli/errors/CodeFrame.hpp>
 
+#include <filesystem>
 #include <iostream>
 #include <memory>
+#include <optional>
+#include <regex>
 #include <string>
+#include <string_view>
 
 #include <vix/cli/Style.hpp>
 
@@ -62,6 +66,122 @@ namespace vix::cli::errors::template_rules
 
       return false;
     }
+
+    bool is_system_path(std::string_view path) noexcept
+    {
+      return path.find("/usr/include/") != std::string_view::npos ||
+             path.find("/usr/lib/") != std::string_view::npos ||
+             path.find("/usr/local/include/") != std::string_view::npos ||
+             path.find("/usr/local/lib/") != std::string_view::npos ||
+             path.find("/lib/") != std::string_view::npos ||
+             path.find("/lib64/") != std::string_view::npos;
+    }
+
+    bool is_user_path(std::string_view path) noexcept
+    {
+      if (path.empty())
+        return false;
+
+      if (is_system_path(path))
+        return false;
+
+      return path.find(".cpp") != std::string_view::npos ||
+             path.find(".cc") != std::string_view::npos ||
+             path.find(".cxx") != std::string_view::npos ||
+             path.find(".hpp") != std::string_view::npos ||
+             path.find(".hh") != std::string_view::npos ||
+             path.find(".h") != std::string_view::npos;
+    }
+
+    vix::cli::errors::CompilerError make_location(
+        const std::string &file,
+        int line,
+        int column,
+        const std::string &message)
+    {
+      vix::cli::errors::CompilerError out;
+      out.file = file;
+      out.line = line;
+      out.column = column > 0 ? column : 1;
+      out.message = message;
+      return out;
+    }
+
+    std::optional<vix::cli::errors::CompilerError>
+    try_extract_first_user_location_from_log(
+        const std::string &log,
+        const std::string &message)
+    {
+      static const std::regex re(
+          R"((/[^:\n]+?\.(?:c|cc|cpp|cxx|h|hpp|hh)):(\d+):(\d+))",
+          std::regex::ECMAScript);
+
+      std::smatch match;
+      std::string::const_iterator it = log.begin();
+
+      while (std::regex_search(it, log.cend(), match, re))
+      {
+        const std::string file = match[1].str();
+        const int line = std::stoi(match[2].str());
+        const int column = std::stoi(match[3].str());
+
+        if (is_user_path(file))
+          return make_location(file, line, column, message);
+
+        it = match.suffix().first;
+      }
+
+      return std::nullopt;
+    }
+
+    const std::string &compiler_log_from_context(
+        const vix::cli::errors::ErrorContext &ctx)
+    {
+      return ctx.buildLog;
+    }
+
+    vix::cli::errors::CompilerError best_location(
+        const vix::cli::errors::CompilerError &err,
+        const vix::cli::errors::ErrorContext &ctx)
+    {
+      const std::string &log = compiler_log_from_context(ctx);
+
+      if (auto user_location =
+              try_extract_first_user_location_from_log(log, err.message))
+      {
+        return *user_location;
+      }
+
+      if (is_user_path(err.file))
+        return err;
+
+      return err;
+    }
+
+    void print_hint_and_at(
+        const vix::cli::errors::CompilerError &location,
+        const vix::cli::errors::CompilerError &original)
+    {
+      std::cerr << YELLOW
+                << "hint: "
+                << RESET
+                << "check the type used at the call site; it does not provide the operation required by this concept"
+                << "\n";
+
+      if (location.file != original.file)
+      {
+        std::cerr << GRAY
+                  << "note: original compiler location was "
+                  << original.file << ":" << original.line << ":" << original.column
+                  << RESET << "\n";
+      }
+
+      std::cerr << GREEN
+                << "at: "
+                << RESET
+                << location.file << ":" << location.line << ":" << location.column
+                << "\n";
+    }
   } // namespace
 
   class ConceptConstraintFailureRule final : public ITemplateErrorRule
@@ -84,23 +204,20 @@ namespace vix::cli::errors::template_rules
         const vix::cli::errors::CompilerError &err,
         const vix::cli::errors::ErrorContext &ctx) const override
     {
+      const auto location = best_location(err, ctx);
+
       std::cerr << RED
                 << "error: concept constraint not satisfied"
                 << RESET << "\n";
 
-      printCodeFrame(err, ctx);
+      CodeFrameOptions options;
+      options.contextLines = 2;
+      options.maxLineWidth = 120;
+      options.tabWidth = 4;
 
-      std::cerr << YELLOW
-                << "hint: "
-                << RESET
-                << "check that the type provides the operations, nested types, and return types required by the concept"
-                << "\n";
+      printCodeFrame(location, ctx, options);
 
-      std::cerr << GREEN
-                << "at: "
-                << RESET
-                << err.file << ":" << err.line << ":" << err.column
-                << "\n";
+      print_hint_and_at(location, err);
 
       return true;
     }