ccls/src/project.cc

#include "project.h"

#include "cache_manager.h"
#include "clang_utils.h"
#include "filesystem.hh"
#include "language.h"
#include "match.h"
#include "platform.h"
#include "queue_manager.h"
#include "serializers/json.h"
#include "timer.h"
#include "utils.h"
#include "working_files.h"

#include <clang/Driver/Options.h>
#include <llvm/ADT/ArrayRef.h>
#include <llvm/Option/ArgList.h>
#include <llvm/Option/OptTable.h>
#include <llvm/Support/MemoryBuffer.h>
#include <llvm/Support/LineIterator.h>
using namespace clang;
using namespace llvm;
using namespace llvm::opt;

#include <clang-c/CXCompilationDatabase.h>
#include <doctest/doctest.h>
#include <rapidjson/writer.h>
#include <loguru.hpp>

#if defined(__unix__) || defined(__APPLE__)
#include <unistd.h>
#endif

#include <limits>
#include <unordered_set>
#include <vector>

struct CompileCommandsEntry {
  std::string directory;
  std::string file;
  std::string command;
  std::vector<std::string> args;

  std::string ResolveIfRelative(std::string path) const {
    if (sys::path::is_absolute(path))
      return path;
    SmallString<256> Ret;
    sys::path::append(Ret, directory, path);
    return Ret.str();
  }
};
MAKE_REFLECT_STRUCT(CompileCommandsEntry, directory, file, command, args);

namespace {

enum class ProjectMode { CompileCommandsJson, DotCcls, ExternalCommand };

struct ProjectConfig {
  std::unordered_set<std::string> quote_dirs;
  std::unordered_set<std::string> angle_dirs;
  std::vector<std::string> extra_flags;
  std::string project_dir;
  ProjectMode mode = ProjectMode::CompileCommandsJson;
};

enum OptionClass {
  EqOrJoinOrSep,
  EqOrSep,
  JoinOrSep,
  Separate,
};

Project::Entry GetCompilationEntryFromCompileCommandEntry(
    ProjectConfig* config,
    const CompileCommandsEntry& entry) {
  Project::Entry result;
  result.filename = entry.file;
  const std::string base_name = sys::path::filename(entry.file);

  // Expand %c %cpp %clang
  std::vector<std::string> args;
  const LanguageId lang = SourceFileLanguage(entry.file);
  for (const std::string& arg : entry.args) {
    if (arg.compare(0, 3, "%c ") == 0) {
      if (lang == LanguageId::C)
        args.push_back(arg.substr(3));
    } else if (arg.compare(0, 5, "%cpp ") == 0) {
      if (lang == LanguageId::Cpp)
        args.push_back(arg.substr(5));
    } else if (arg == "%clang") {
      args.push_back(lang == LanguageId::Cpp ? "clang++" : "clang");
    } else {
      args.push_back(arg);
    }
  }
  if (args.empty())
    return result;

  std::unique_ptr<OptTable> Opts = driver::createDriverOptTable();
  unsigned MissingArgIndex, MissingArgCount;
  std::vector<const char*> cargs;
  for (auto& arg : args)
    cargs.push_back(arg.c_str());
  InputArgList Args =
      Opts->ParseArgs(makeArrayRef(cargs), MissingArgIndex, MissingArgCount,
                      driver::options::CC1Option);

  using namespace clang::driver::options;
  for (const auto* A :
       Args.filtered(OPT_I, OPT_c_isystem, OPT_cxx_isystem, OPT_isystem))
    config->angle_dirs.insert(entry.ResolveIfRelative(A->getValue()));
  for (const auto* A : Args.filtered(OPT_I, OPT_iquote))
    config->quote_dirs.insert(entry.ResolveIfRelative(A->getValue()));

  for (size_t i = 1; i < args.size(); i++)
    // This is most likely the file path we will be passing to clang. The
    // path needs to be absolute, otherwise clang_codeCompleteAt is extremely
    // slow. See
    // https://github.com/cquery-project/cquery/commit/af63df09d57d765ce12d40007bf56302a0446678.
    if (args[i][0] != '-' && EndsWith(args[i], base_name)) {
      args[i] = entry.ResolveIfRelative(args[i]);
      continue;
    }

  // We don't do any special processing on user-given extra flags.
  for (const auto& flag : config->extra_flags)
    args.push_back(flag);

  if (!Args.hasArg(OPT_resource_dir))
    args.push_back("-resource-dir=" + g_config->clang.resourceDir);
  if (!Args.hasArg(OPT_working_directory))
    args.push_back("-working-directory=" + entry.directory);

  // There could be a clang version mismatch between what the project uses and
  // what ccls uses. Make sure we do not emit warnings for mismatched options.
  args.push_back("-Wno-unknown-warning-option");

  // Using -fparse-all-comments enables documentation in the indexer and in
  // code completion.
  if (g_config->index.comments > 1)
    args.push_back("-fparse-all-comments");

  result.args = std::move(args);
  return result;
}

std::vector<std::string> ReadCompilerArgumentsFromFile(
    const std::string& path) {
  auto MBOrErr = MemoryBuffer::getFile(path);
  if (!MBOrErr) return {};
  std::vector<std::string> args;
  for (line_iterator I(*MBOrErr.get(), true, '#'), E; I != E; ++I)
    args.push_back(*I);
  return args;
}

std::vector<Project::Entry> LoadFromDirectoryListing(ProjectConfig* config) {
  std::vector<Project::Entry> result;
  config->mode = ProjectMode::DotCcls;
  SmallString<256> Path;
  sys::path::append(Path, config->project_dir, ".ccls");
  LOG_IF_S(WARNING, !sys::fs::exists(Path) && config->extra_flags.empty())
      << "ccls has no clang arguments. Use either "
         "compile_commands.json or .ccls, See ccls README for "
         "more information.";

  std::unordered_map<std::string, std::vector<std::string>> folder_args;
  std::vector<std::string> files;

  GetFilesInFolder(config->project_dir, true /*recursive*/,
                   true /*add_folder_to_path*/,
                   [&folder_args, &files](const std::string& path) {
                     if (SourceFileLanguage(path) != LanguageId::Unknown) {
                       files.push_back(path);
                     } else if (sys::path::filename(path) == ".ccls") {
                       LOG_S(INFO) << "Using .ccls arguments from " << path;
                       folder_args.emplace(sys::path::parent_path(path),
                                           ReadCompilerArgumentsFromFile(path));
                     }
                   });

  const std::string& project_dir = config->project_dir;
  const auto& project_dir_args = folder_args[project_dir];
  LOG_IF_S(INFO, !project_dir_args.empty())
      << "Using .ccls arguments " << StringJoin(project_dir_args);

  auto GetCompilerArgumentForFile = [&project_dir, &folder_args](std::string cur) {
    while (!(cur = sys::path::parent_path(cur)).empty()) {
      auto it = folder_args.find(cur);
      if (it != folder_args.end())
        return it->second;
      std::string normalized = NormalizePath(cur);
      // Break if outside of the project root.
      if (normalized.size() <= project_dir.size() ||
          normalized.compare(0, project_dir.size(), project_dir) != 0)
        break;
    }
    return folder_args[project_dir];
  };

  for (const std::string& file : files) {
    CompileCommandsEntry e;
    e.directory = config->project_dir;
    e.file = file;
    e.args = GetCompilerArgumentForFile(file);
    if (e.args.empty())
      e.args.push_back("%clang");  // Add a Dummy.
    e.args.push_back(e.file);
    result.push_back(GetCompilationEntryFromCompileCommandEntry(config, e));
  }

  return result;
}

std::vector<Project::Entry> LoadCompilationEntriesFromDirectory(
    ProjectConfig* project,
    const std::string& opt_compilation_db_dir) {
  // If there is a .ccls file always load using directory listing.
  SmallString<256> Path;
  sys::path::append(Path, project->project_dir, ".ccls");
  if (sys::fs::exists(Path))
    return LoadFromDirectoryListing(project);

  // If |compilationDatabaseCommand| is specified, execute it to get the compdb.
  std::string comp_db_dir;
  Path.clear();
  if (g_config->compilationDatabaseCommand.empty()) {
    project->mode = ProjectMode::CompileCommandsJson;
    // Try to load compile_commands.json, but fallback to a project listing.
    comp_db_dir = opt_compilation_db_dir.empty() ? project->project_dir
                                                 : opt_compilation_db_dir;
    sys::path::append(Path, comp_db_dir, "compile_commands.json");
  } else {
    project->mode = ProjectMode::ExternalCommand;
#ifdef _WIN32
    // TODO
#else
    char tmpdir[] = "/tmp/ccls-compdb-XXXXXX";
    if (!mkdtemp(tmpdir))
      return {};
    comp_db_dir = tmpdir;
    sys::path::append(Path, comp_db_dir, "compile_commands.json");
    rapidjson::StringBuffer input;
    rapidjson::Writer<rapidjson::StringBuffer> writer(input);
    JsonWriter json_writer(&writer);
    Reflect(json_writer, *g_config);
    std::string contents = GetExternalCommandOutput(
        std::vector<std::string>{g_config->compilationDatabaseCommand,
                                 project->project_dir},
        input.GetString());
    FILE* fout = fopen(Path.c_str(), "wb");
    fwrite(contents.c_str(), contents.size(), 1, fout);
    fclose(fout);
#endif
  }

  CXCompilationDatabase_Error cx_db_load_error;
  CXCompilationDatabase cx_db = clang_CompilationDatabase_fromDirectory(
      comp_db_dir.c_str(), &cx_db_load_error);
  if (!g_config->compilationDatabaseCommand.empty()) {
#ifdef _WIN32
  // TODO
#else
    unlink(Path.c_str());
    rmdir(comp_db_dir.c_str());
#endif
  }
  if (cx_db_load_error == CXCompilationDatabase_CanNotLoadDatabase) {
    LOG_S(INFO) << "unable to load " << Path.c_str()
                << "; using directory listing instead.";
    return LoadFromDirectoryListing(project);
  }

  LOG_S(INFO) << "loaded " << Path.c_str();

  Timer clang_time;
  Timer our_time;
  clang_time.Pause();
  our_time.Pause();

  clang_time.Resume();
  CXCompileCommands cx_commands =
      clang_CompilationDatabase_getAllCompileCommands(cx_db);
  unsigned int num_commands = clang_CompileCommands_getSize(cx_commands);
  clang_time.Pause();

  std::vector<Project::Entry> result;
  for (unsigned int i = 0; i < num_commands; i++) {
    clang_time.Resume();
    CXCompileCommand cx_command =
        clang_CompileCommands_getCommand(cx_commands, i);

    std::string directory =
        ToString(clang_CompileCommand_getDirectory(cx_command));
    std::string relative_filename =
        ToString(clang_CompileCommand_getFilename(cx_command));

    unsigned num_args = clang_CompileCommand_getNumArgs(cx_command);
    CompileCommandsEntry entry;
    entry.args.reserve(num_args);
    for (unsigned j = 0; j < num_args; ++j) {
      entry.args.push_back(
          ToString(clang_CompileCommand_getArg(cx_command, j)));
    }
    clang_time.Pause();  // TODO: don't call ToString in this block.
    // LOG_S(INFO) << "Got args " << StringJoin(entry.args);

    our_time.Resume();
    entry.directory = directory;
    entry.file = entry.ResolveIfRelative(relative_filename);

    result.push_back(
        GetCompilationEntryFromCompileCommandEntry(project, entry));
    our_time.Pause();
  }

  clang_time.Resume();
  clang_CompileCommands_dispose(cx_commands);
  clang_CompilationDatabase_dispose(cx_db);
  clang_time.Pause();

  clang_time.ResetAndPrint("compile_commands.json clang time");
  our_time.ResetAndPrint("compile_commands.json our time");
  return result;
}

// Computes a score based on how well |a| and |b| match. This is used for
// argument guessing.
int ComputeGuessScore(std::string_view a, std::string_view b) {
  // Increase score based on common prefix and suffix. Prefixes are prioritized.
  if (a.size() < b.size())
    std::swap(a, b);
  size_t i = std::mismatch(a.begin(), a.end(), b.begin()).first - a.begin();
  size_t j = std::mismatch(a.rbegin(), a.rend(), b.rbegin()).first - a.rbegin();
  int score = 10 * i + j;
  if (i + j < b.size())
    score -= 100 * (std::count(a.begin() + i, a.end() - j, '/') +
                    std::count(b.begin() + i, b.end() - j, '/'));
  return score;
}

}  // namespace

void Project::Load(const std::string& root_directory) {
  // Load data.
  ProjectConfig project;
  project.extra_flags = g_config->clang.extraArgs;
  project.project_dir = root_directory;
  entries = LoadCompilationEntriesFromDirectory(
      &project, g_config->compilationDatabaseDirectory);

  // Cleanup / postprocess include directories.
  quote_include_directories.assign(project.quote_dirs.begin(),
                                   project.quote_dirs.end());
  angle_include_directories.assign(project.angle_dirs.begin(),
                                   project.angle_dirs.end());
  for (std::string& path : quote_include_directories) {
    EnsureEndsInSlash(path);
    LOG_S(INFO) << "quote_include_dir: " << path;
  }
  for (std::string& path : angle_include_directories) {
    EnsureEndsInSlash(path);
    LOG_S(INFO) << "angle_include_dir: " << path;
  }

  // Setup project entries.
  std::lock_guard<std::mutex> lock(mutex_);
  absolute_path_to_entry_index_.reserve(entries.size());
  for (size_t i = 0; i < entries.size(); ++i) {
    entries[i].id = i;
    absolute_path_to_entry_index_[entries[i].filename] = i;
  }
}

void Project::SetFlagsForFile(
    const std::vector<std::string>& flags,
    const std::string& path) {
  std::lock_guard<std::mutex> lock(mutex_);
  auto it = absolute_path_to_entry_index_.find(path);
  if (it != absolute_path_to_entry_index_.end()) {
    // The entry already exists in the project, just set the flags.
    this->entries[it->second].args = flags;
  } else {
    // Entry wasn't found, so we create a new one.
    Entry entry;
    entry.is_inferred = false;
    entry.filename = path;
    entry.args = flags;
    this->entries.emplace_back(entry);
  }
}

Project::Entry Project::FindCompilationEntryForFile(
    const std::string& filename) {
  {
    std::lock_guard<std::mutex> lock(mutex_);
    auto it = absolute_path_to_entry_index_.find(filename);
    if (it != absolute_path_to_entry_index_.end())
      return entries[it->second];
  }

  // We couldn't find the file. Try to infer it.
  // TODO: Cache inferred file in a separate array (using a lock or similar)
  Entry* best_entry = nullptr;
  int best_score = std::numeric_limits<int>::min();
  for (Entry& entry : entries) {
    int score = ComputeGuessScore(filename, entry.filename);
    if (score > best_score) {
      best_score = score;
      best_entry = &entry;
    }
  }

  Project::Entry result;
  result.is_inferred = true;
  result.filename = filename;
  if (!best_entry) {
    result.args.push_back("%clang");
    result.args.push_back(filename);
  } else {
    result.args = best_entry->args;

    // |best_entry| probably has its own path in the arguments. We need to remap
    // that path to the new filename.
    std::string best_entry_base_name = sys::path::filename(best_entry->filename);
    for (std::string& arg : result.args) {
      try {
        if (arg == best_entry->filename ||
            sys::path::filename(arg) == best_entry_base_name)
          arg = filename;
      } catch (...) {
      }
    }
  }

  return result;
}

void Project::ForAllFilteredFiles(
    std::function<void(int i, const Entry& entry)> action) {
  GroupMatch matcher(g_config->index.whitelist, g_config->index.blacklist);
  for (int i = 0; i < entries.size(); ++i) {
    const Project::Entry& entry = entries[i];
    std::string failure_reason;
    if (matcher.IsMatch(entry.filename, &failure_reason))
      action(i, entries[i]);
    else if (g_config->index.logSkippedPaths) {
      LOG_S(INFO) << "[" << i + 1 << "/" << entries.size() << "]: Failed "
                  << failure_reason << "; skipping " << entry.filename;
    }
  }
}

void Project::Index(QueueManager* queue,
                    WorkingFiles* wfiles,
                    lsRequestId id) {
  ForAllFilteredFiles([&](int i, const Project::Entry& entry) {
    std::optional<std::string> content = ReadContent(entry.filename);
    if (!content) {
      LOG_S(ERROR) << "When loading project, canont read file "
                   << entry.filename;
      return;
    }
    bool is_interactive = wfiles->GetFileByFilename(entry.filename) != nullptr;
    queue->index_request.PushBack(Index_Request(entry.filename, entry.args,
                                                is_interactive, *content, id));
  });
  // Dummy request to indicate that project is loaded and
  // trigger refreshing semantic highlight for all working files.
  queue->index_request.PushBack(Index_Request("", {}, false, ""));
}

TEST_SUITE("Project") {
  void CheckFlags(const std::string& directory, const std::string& file,
                  std::vector<std::string> raw,
                  std::vector<std::string> expected) {
    g_config = std::make_unique<Config>();
    g_config->clang.resourceDir = "/w/resource_dir/";
    ProjectConfig project;
    project.project_dir = "/w/c/s/";

    CompileCommandsEntry entry;
    entry.directory = directory;
    entry.args = raw;
    entry.file = file;
    Project::Entry result =
        GetCompilationEntryFromCompileCommandEntry(&project, entry);

    if (result.args != expected) {
      fprintf(stderr, "Raw:      %s\n", StringJoin(raw).c_str());
      fprintf(stderr, "Expected: %s\n", StringJoin(expected).c_str());
      fprintf(stderr, "Actual:   %s\n", StringJoin(result.args).c_str());
    }
    REQUIRE(result.args == expected);
  }

  void CheckFlags(std::vector<std::string> raw,
                  std::vector<std::string> expected) {
    CheckFlags("/dir/", "file.cc", raw, expected);
  }

  TEST_CASE("strip meta-compiler invocations") {
    CheckFlags(
        /* raw */ {"clang", "-lstdc++", "myfile.cc"},
        /* expected */
        {"clang", "-lstdc++", "/dir/myfile.cc",
         "-resource-dir=/w/resource_dir/", "-working-directory=/dir/",
         "-Wno-unknown-warning-option", "-fparse-all-comments"});

    CheckFlags(
        /* raw */ {"clang.exe"},
        /* expected */
        {"clang.exe", "-resource-dir=/w/resource_dir/",
         "-working-directory=/dir/", "-Wno-unknown-warning-option",
         "-fparse-all-comments"});
  }

#ifdef _WIN32
  TEST_CASE("Windows path normalization") {
    CheckFlags("E:/workdir", "E:/workdir/bar.cc", /* raw */ {"clang", "bar.cc"},
               /* expected */
               {"clang", "-working-directory=E:/workdir", "E:/workdir/bar.cc",
                "-resource-dir=/w/resource_dir/", "-Wno-unknown-warning-option",
                "-fparse-all-comments"});

    CheckFlags("E:/workdir", "E:/workdir/bar.cc",
               /* raw */ {"clang", "E:/workdir/bar.cc"},
               /* expected */
               {"clang", "-working-directory=E:/workdir", "E:/workdir/bar.cc",
                "-resource-dir=/w/resource_dir/", "-Wno-unknown-warning-option",
                "-fparse-all-comments"});

    CheckFlags("E:/workdir", "E:/workdir/bar.cc",
               /* raw */ {"clang-cl.exe", "/I./test", "E:/workdir/bar.cc"},
               /* expected */
               {"clang-cl.exe", "-working-directory=E:/workdir",
                "/I&E:/workdir/./test", "E:/workdir/bar.cc",
                "-resource-dir=/w/resource_dir/", "-Wno-unknown-warning-option",
                "-fparse-all-comments"});

    CheckFlags("E:/workdir", "E:/workdir/bar.cc",
               /* raw */
               {"cl.exe", "/I../third_party/test/include", "E:/workdir/bar.cc"},
               /* expected */
               {"cl.exe", "-working-directory=E:/workdir",
                "/I&E:/workdir/../third_party/test/include",
                "E:/workdir/bar.cc", "-resource-dir=/w/resource_dir/",
                "-Wno-unknown-warning-option", "-fparse-all-comments"});
  }
#endif

  TEST_CASE("Path in args") {
    CheckFlags(
        "/home/user", "/home/user/foo/bar.c",
        /* raw */ {"cc", "-O0", "foo/bar.c"},
        /* expected */
        {"cc", "-O0", "/home/user/foo/bar.c", "-resource-dir=/w/resource_dir/",
         "-working-directory=/home/user", "-Wno-unknown-warning-option",
         "-fparse-all-comments"});
  }

  TEST_CASE("Directory extraction") {
    g_config = std::make_unique<Config>();
    ProjectConfig config;
    config.project_dir = "/w/c/s/";

    CompileCommandsEntry entry;
    entry.directory = "/base";
    entry.args = {"clang",
                  "-I/a_absolute1",
                  "--foobar",
                  "-I",
                  "/a_absolute2",
                  "--foobar",
                  "-Ia_relative1",
                  "--foobar",
                  "-isystem",
                  "a_relative2",
                  "--foobar",
                  "-iquote/q_absolute1",
                  "--foobar",
                  "-iquote",
                  "/q_absolute2",
                  "--foobar",
                  "-iquoteq_relative1",
                  "--foobar",
                  "-iquote",
                  "q_relative2",
                  "--foobar",
                  "foo.cc"};
    entry.file = "foo.cc";
    Project::Entry result =
        GetCompilationEntryFromCompileCommandEntry(&config, entry);

    std::unordered_set<std::string> angle_expected{
        "/a_absolute1", "/a_absolute2", "/base/a_relative1",
        "/base/a_relative2"};
    std::unordered_set<std::string> quote_expected{
        "/a_absolute1",     "/a_absolute2", "/base/a_relative1",
        "/q_absolute1",     "/q_absolute2", "/base/q_relative1",
        "/base/q_relative2"};
    REQUIRE(config.angle_dirs == angle_expected);
    REQUIRE(config.quote_dirs == quote_expected);
  }

  TEST_CASE("Entry inference") {
    Project p;
    {
      Project::Entry e;
      e.args = {"arg1"};
      e.filename = "/a/b/c/d/bar.cc";
      p.entries.push_back(e);
    }
    {
      Project::Entry e;
      e.args = {"arg2"};
      e.filename = "/a/b/c/baz.cc";
      p.entries.push_back(e);
    }

    // Guess at same directory level, when there are parent directories.
    {
      std::optional<Project::Entry> entry =
          p.FindCompilationEntryForFile("/a/b/c/d/new.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"arg1"});
    }

    // Guess at same directory level, when there are child directories.
    {
      std::optional<Project::Entry> entry =
          p.FindCompilationEntryForFile("/a/b/c/new.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"arg2"});
    }

    // Guess at new directory (use the closest parent directory).
    {
      std::optional<Project::Entry> entry =
          p.FindCompilationEntryForFile("/a/b/c/new/new.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"arg2"});
    }
  }

  TEST_CASE("Entry inference remaps file names") {
    Project p;
    {
      Project::Entry e;
      e.args = {"a", "b", "aaaa.cc", "d"};
      e.filename = "absolute/aaaa.cc";
      p.entries.push_back(e);
    }

    {
      std::optional<Project::Entry> entry = p.FindCompilationEntryForFile("ee.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"a", "b", "ee.cc", "d"});
    }
  }

  TEST_CASE("Entry inference prefers same file endings") {
    Project p;
    {
      Project::Entry e;
      e.args = {"arg1"};
      e.filename = "common/simple_browsertest.cc";
      p.entries.push_back(e);
    }
    {
      Project::Entry e;
      e.args = {"arg2"};
      e.filename = "common/simple_unittest.cc";
      p.entries.push_back(e);
    }
    {
      Project::Entry e;
      e.args = {"arg3"};
      e.filename = "common/a/simple_unittest.cc";
      p.entries.push_back(e);
    }

    // Prefer files with the same ending.
    {
      std::optional<Project::Entry> entry =
          p.FindCompilationEntryForFile("my_browsertest.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"arg1"});
    }
    {
      std::optional<Project::Entry> entry =
          p.FindCompilationEntryForFile("my_unittest.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"arg2"});
    }
    {
      std::optional<Project::Entry> entry =
          p.FindCompilationEntryForFile("common/my_browsertest.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"arg1"});
    }
    {
      std::optional<Project::Entry> entry =
          p.FindCompilationEntryForFile("common/my_unittest.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"arg2"});
    }

    // Prefer the same directory over matching file-ending.
    {
      std::optional<Project::Entry> entry =
          p.FindCompilationEntryForFile("common/a/foo.cc");
      REQUIRE(entry.has_value());
      REQUIRE(entry->args == std::vector<std::string>{"arg3"});
    }
  }
}