From eed8ef91d62fc19c33c9d8891a5881d5c3c7d3ab Mon Sep 17 00:00:00 2001
From: Guo-Shiyu <im.shiyu1225@gmail.com>
Date: Mon, 25 Aug 2025 15:18:54 +0800
Subject: [PATCH 1/8] Feat: better load and fetch compile command.

---
 include/Compiler/Command.h   |  8 +++-
 include/Protocol/Lifecycle.h |  2 +-
 src/Compiler/Command.cpp     | 49 ++++++++++++++++------
 src/Server/Document.cpp      |  9 ++--
 src/Server/Lifecycle.cpp     | 81 ++++++++++++++++++++++++++++++++----
 5 files changed, 120 insertions(+), 29 deletions(-)

diff --git a/include/Compiler/Command.h b/include/Compiler/Command.h
index 990a99bd..87c66d07 100644
--- a/include/Compiler/Command.h
+++ b/include/Compiler/Command.h
@@ -112,6 +112,10 @@ class CompilationDatabase {
     auto get_command(this Self& self, llvm::StringRef file, CommandOptions options = {})
         -> LookupInfo;
 
+private:
+    /// If file not found in CDB file, try to guess commands or use the default case.
+    auto guess_or_fallback(this Self& self, llvm::StringRef file) -> LookupInfo;
+
 private:
     /// The memory pool to hold all cstring and command list.
     llvm::BumpPtrAllocator allocator;
@@ -128,10 +132,10 @@ class CompilationDatabase {
     llvm::DenseSet<std::uint32_t> filtered_options;
 
     /// A map between file path and its canonical command list.
-    llvm::DenseMap<const void*, CommandInfo> command_infos;
+    llvm::DenseMap<const char*, CommandInfo> command_infos;
 
     /// A map between driver path and its query driver info.
-    llvm::DenseMap<const void*, DriverInfo> driver_infos;
+    llvm::DenseMap<const char*, DriverInfo> driver_infos;
 };
 
 }  // namespace clice
diff --git a/include/Protocol/Lifecycle.h b/include/Protocol/Lifecycle.h
index 9c804ec3..bb48f561 100644
--- a/include/Protocol/Lifecycle.h
+++ b/include/Protocol/Lifecycle.h
@@ -14,7 +14,7 @@ struct LSPInfo {
     std::string name;
 
     /// The version of server or client.
-    std::string verion;
+    std::string version;
 };
 
 struct WindowCapacities {};
diff --git a/src/Compiler/Command.cpp b/src/Compiler/Command.cpp
index 7aadeeb7..eb9680da 100644
--- a/src/Compiler/Command.cpp
+++ b/src/Compiler/Command.cpp
@@ -148,6 +148,7 @@ auto CompilationDatabase::query_driver(this Self& self, llvm::StringRef driver)
     bool keep_output_file = true;
     auto clean_up = llvm::make_scope_exit([&output_path, &keep_output_file]() {
         if(keep_output_file) {
+            log::warn("Query driver failed, output file:{}", output_path);
             return;
         }
 
@@ -398,11 +399,11 @@ auto CompilationDatabase::load_commands(this Self& self, llvm::StringRef json_co
 
     auto json = json::parse(json_content);
     if(!json) {
-        return std::unexpected(std::format("Fail to parse json: {}", json.takeError()));
+        return std::unexpected(std::format("parse json failed: {}", json.takeError()));
     }
 
     if(json->kind() != json::Value::Array) {
-        return std::unexpected("Compilation Database must be an array of object");
+        return std::unexpected("compile_commands.json must be an array of object");
     }
 
     /// FIXME: warn illegal item.
@@ -457,29 +458,24 @@ auto CompilationDatabase::get_command(this Self& self, llvm::StringRef file, Com
         info.dictionary = it->second.dictionary;
         info.arguments = it->second.arguments;
     } else {
-        /// FIXME: Use a better way to handle fallback command.
-        info.dictionary = {};
-        info.arguments = {
-            self.save_string("clang++").data(),
-            self.save_string("-std=c++20").data(),
-        };
+        info = self.guess_or_fallback(file);
     }
 
-    auto append_argument = [&](llvm::StringRef argument) {
+    auto record = [&info, &self](llvm::StringRef argument) {
         info.arguments.emplace_back(self.save_string(argument).data());
     };
 
     if(options.query_driver) {
         llvm::StringRef driver = info.arguments[0];
         if(auto driver_info = self.query_driver(driver)) {
-            append_argument("-nostdlibinc");
+            record("-nostdlibinc");
 
             /// FIXME: Use target information here, this is useful for cross compilation.
 
             /// FIXME: Cache -I so that we can append directly, avoid duplicate lookup.
             for(auto& system_header: driver_info->system_includes) {
-                append_argument("-I");
-                append_argument(system_header);
+                record("-I");
+                record(system_header);
             }
         } else if(!options.suppress_log) {
             log::warn("Failed to query driver:{}, error:{}", driver, driver_info.error());
@@ -487,10 +483,37 @@ auto CompilationDatabase::get_command(this Self& self, llvm::StringRef file, Com
     }
 
     if(options.resource_dir) {
-        append_argument(std::format("-resource-dir={}", fs::resource_dir));
+        record(std::format("-resource-dir={}", fs::resource_dir));
     }
 
     info.arguments.emplace_back(file.data());
+    /// TODO: apply rules in clice.toml.
+    return info;
+}
+
+auto CompilationDatabase::guess_or_fallback(this Self& self, llvm::StringRef file) -> LookupInfo {
+    // Try to guess command from other file in same directory or parent directory
+    llvm::StringRef dir = path::parent_path(file);
+    while(!dir.empty()) {
+        for(const auto& [other_file, info]: self.command_infos) {
+            if(llvm::StringRef other = other_file; !other.starts_with(dir)) {
+                continue;
+            }
+            log::info("Guess command for:{}, from existed file: {}", file, other_file);
+            return LookupInfo{info.dictionary, info.arguments};
+        }
+        dir = path::parent_path(dir);
+    }
+
+    /// FIXME: use a better default case.
+    // Fallback to default case.
+    LookupInfo info;
+    info.dictionary = {};
+    info.arguments = {
+        self.save_string("clang++").data(),
+        self.save_string("-std=c++20").data(),
+    };
+
     return info;
 }
 
diff --git a/src/Server/Document.cpp b/src/Server/Document.cpp
index f37713e1..b0821e23 100644
--- a/src/Server/Document.cpp
+++ b/src/Server/Document.cpp
@@ -194,8 +194,6 @@ async::Task<bool> build_pch_task(CompilationDatabase::LookupInfo& info,
     params.diagnostics = diagnostics;
     params.add_remapped_file(path, content, bound);
 
-    PCHInfo pch;
-
     std::string command;
     for(auto argument: params.arguments) {
         command += " ";
@@ -203,13 +201,14 @@ async::Task<bool> build_pch_task(CompilationDatabase::LookupInfo& info,
     }
 
     log::info("Start building PCH for {}, command: [{}]", path, command);
+    command.clear();
 
-    std::string message;
+    PCHInfo pch;
+    std::string message = std::move(command);  // reuse buffer
     std::vector<feature::DocumentLink> links;
 
     bool success = co_await async::submit([&params, &pch, &message, &links] -> bool {
-        /// PCH file is written until destructing, Add a single block
-        /// for it.
+        /// PCH file is written until destructing, Add a single block for it.
         auto unit = compile(params, pch);
         if(!unit) {
             message = std::move(unit.error());
diff --git a/src/Server/Lifecycle.cpp b/src/Server/Lifecycle.cpp
index 8635f8f5..5683a1ab 100644
--- a/src/Server/Lifecycle.cpp
+++ b/src/Server/Lifecycle.cpp
@@ -1,11 +1,81 @@
 #include "Server/Server.h"
 
+#include <filesystem>
+
 namespace clice {
 
+namespace {
+
+namespace stdfs = std::filesystem;
+
+/// Load compile commands from given directories. If no valid commands are found,
+/// search recursively from the workspace directory.
+void load_compile_commands(CompilationDatabase& database,
+                           const std::vector<std::string>& compile_commands_dirs,
+                           const std::string& workspace) {
+    auto try_load = [&database](const std::string& dir) {
+        std::string filepath = dir + "/compile_commands.json";
+        auto content = fs::read(filepath);
+        if(!content) {
+            log::warn("Failed to read CDB file: {}, {}", filepath, content.error());
+            return false;
+        }
+
+        auto load = database.load_commands(*content);
+        if(!load) {
+            log::warn("Failed to load CDB file: {}. {}", filepath, load.error());
+            return false;
+        }
+
+        log::info("Load CDB file: {} successfully, {} items loaded", filepath, load->size());
+        return true;
+    };
+
+    if(std::ranges::any_of(compile_commands_dirs, try_load)) {
+        return;
+    }
+
+    log::info(
+        "Can not found any valid CDB file from given directories, search recursively from workspace: {} ...",
+        workspace);
+
+    auto recursive_search = [&try_load](this auto&& self, const stdfs::path& dir) -> bool {
+        if(!stdfs::exists(dir) || !stdfs::is_directory(dir)) {
+            return false;
+        }
+
+        // Skip hidden directories.
+        if(dir.filename().string().starts_with('.')) {
+            return false;
+        }
+
+        if(try_load(dir)) {
+            return true;
+        }
+
+        for(const auto& entry: stdfs::directory_iterator(dir)) {
+            if(self(entry.path())) {
+                return true;
+            }
+        }
+
+        return false;
+    };
+
+    if(recursive_search(workspace)) {
+        return;
+    }
+
+    /// TODO: Add a default command in clice.toml. Or load commands from .clangd ?
+    log::warn("Can not found any valid CDB file in current workspace, fallback to default mode.");
+}
+
+}  // namespace
+
 async::Task<json::Value> Server::on_initialize(proto::InitializeParams params) {
     log::info("Initialize from client: {}, version: {}",
               params.clientInfo.name,
-              params.clientInfo.verion);
+              params.clientInfo.version);
 
     if(params.workspaceFolders.empty()) {
         log::fatal("The client should provide one workspace folder at least!");
@@ -22,12 +92,7 @@ async::Task<json::Value> Server::on_initialize(proto::InitializeParams params) {
     opening_files.set_capability(config::server.max_active_file);
 
     /// Load compile commands.json
-    for(auto& dir: config::server.compile_commands_dirs) {
-        auto content = fs::read(dir + "/compile_commands.json");
-        if(content) {
-            auto updated = database.load_commands(*content);
-        }
-    }
+    load_compile_commands(database, config::server.compile_commands_dirs, workspace);
 
     /// Load cache info.
     load_cache_info();
@@ -35,7 +100,7 @@ async::Task<json::Value> Server::on_initialize(proto::InitializeParams params) {
     proto::InitializeResult result;
     auto& [info, capabilities] = result;
     info.name = "clice";
-    info.verion = "0.0.1";
+    info.version = "0.0.1";
 
     capabilities.positionEncoding = "utf-16";
 

From 3d07ffece7dcf4f4330bb4eae8bdd89a3a1d0804 Mon Sep 17 00:00:00 2001
From: Guo-Shiyu <im.shiyu1225@gmail.com>
Date: Mon, 25 Aug 2025 15:52:36 +0800
Subject: [PATCH 2/8] Build: fix build on MSVC.

---
 src/Server/Lifecycle.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Server/Lifecycle.cpp b/src/Server/Lifecycle.cpp
index 5683a1ab..5c3131dd 100644
--- a/src/Server/Lifecycle.cpp
+++ b/src/Server/Lifecycle.cpp
@@ -49,7 +49,7 @@ void load_compile_commands(CompilationDatabase& database,
             return false;
         }
 
-        if(try_load(dir)) {
+        if(try_load(dir.string())) {
             return true;
         }
 

From 7ed0c8fcd40ec228943e8a644fa8ffadba93984c Mon Sep 17 00:00:00 2001
From: Guo-Shiyu <im.shiyu1225@gmail.com>
Date: Tue, 26 Aug 2025 15:22:37 +0800
Subject: [PATCH 3/8] Fix: fix by gemini suggestions.

---
 src/Compiler/Command.cpp | 24 +++++++++++++-----------
 src/Server/Lifecycle.cpp |  8 +++++++-
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/src/Compiler/Command.cpp b/src/Compiler/Command.cpp
index eb9680da..7866fb31 100644
--- a/src/Compiler/Command.cpp
+++ b/src/Compiler/Command.cpp
@@ -494,26 +494,28 @@ auto CompilationDatabase::get_command(this Self& self, llvm::StringRef file, Com
 auto CompilationDatabase::guess_or_fallback(this Self& self, llvm::StringRef file) -> LookupInfo {
     // Try to guess command from other file in same directory or parent directory
     llvm::StringRef dir = path::parent_path(file);
-    while(!dir.empty()) {
+
+    // Search up to 3 levels of parent directories
+    int up_level = 0;
+    while(!dir.empty() && up_level < 3) {
+        // If any file in the directory has a command, use that command
         for(const auto& [other_file, info]: self.command_infos) {
-            if(llvm::StringRef other = other_file; !other.starts_with(dir)) {
-                continue;
+            if(llvm::StringRef other = other_file; other.starts_with(dir)) {
+                log::info("Guess command for:{}, from existed file: {}", file, other_file);
+                return LookupInfo{info.dictionary, info.arguments};
             }
-            log::info("Guess command for:{}, from existed file: {}", file, other_file);
-            return LookupInfo{info.dictionary, info.arguments};
         }
         dir = path::parent_path(dir);
+        up_level += 1;
     }
 
     /// FIXME: use a better default case.
     // Fallback to default case.
     LookupInfo info;
-    info.dictionary = {};
-    info.arguments = {
-        self.save_string("clang++").data(),
-        self.save_string("-std=c++20").data(),
-    };
-
+    constexpr const char* fallback[] = {"clang++", "-std=c++20"};
+    for(const char* arg: fallback) {
+        info.arguments.emplace_back(self.save_string(arg).data());
+    }
     return info;
 }
 
diff --git a/src/Server/Lifecycle.cpp b/src/Server/Lifecycle.cpp
index 5c3131dd..ec93b60c 100644
--- a/src/Server/Lifecycle.cpp
+++ b/src/Server/Lifecycle.cpp
@@ -53,7 +53,13 @@ void load_compile_commands(CompilationDatabase& database,
             return true;
         }
 
-        for(const auto& entry: stdfs::directory_iterator(dir)) {
+        std::error_code ec;
+        for(const auto& entry: stdfs::directory_iterator(dir, ec)) {
+            if(ec) {
+                log::warn("Error iterating directory: {}, {}, skipped", dir.string(), ec.message());
+                continue;
+            }
+
             if(self(entry.path())) {
                 return true;
             }

From 4c293ba9fd1d7c16830036a772be309f6a3f784a Mon Sep 17 00:00:00 2001
From: Guo-Shiyu <im.shiyu1225@gmail.com>
Date: Fri, 29 Aug 2025 14:46:55 +0800
Subject: [PATCH 4/8] lint: use llvm::fs api instead of std::filesystem.

---
 src/Server/Lifecycle.cpp | 44 ++++++++++++++--------------------------
 1 file changed, 15 insertions(+), 29 deletions(-)

diff --git a/src/Server/Lifecycle.cpp b/src/Server/Lifecycle.cpp
index ec93b60c..aacc79c5 100644
--- a/src/Server/Lifecycle.cpp
+++ b/src/Server/Lifecycle.cpp
@@ -1,20 +1,17 @@
 #include "Server/Server.h"
 
-#include <filesystem>
-
 namespace clice {
 
 namespace {
 
-namespace stdfs = std::filesystem;
-
 /// Load compile commands from given directories. If no valid commands are found,
 /// search recursively from the workspace directory.
 void load_compile_commands(CompilationDatabase& database,
                            const std::vector<std::string>& compile_commands_dirs,
                            const std::string& workspace) {
+
     auto try_load = [&database](const std::string& dir) {
-        std::string filepath = dir + "/compile_commands.json";
+        std::string filepath = path::join(dir, "compile_commands.json");
         auto content = fs::read(filepath);
         if(!content) {
             log::warn("Failed to read CDB file: {}, {}", filepath, content.error());
@@ -39,37 +36,26 @@ void load_compile_commands(CompilationDatabase& database,
         "Can not found any valid CDB file from given directories, search recursively from workspace: {} ...",
         workspace);
 
-    auto recursive_search = [&try_load](this auto&& self, const stdfs::path& dir) -> bool {
-        if(!stdfs::exists(dir) || !stdfs::is_directory(dir)) {
-            return false;
+    std::error_code ec;
+    for(fs::recursive_directory_iterator it(workspace, ec), end; it != end && !ec;
+        it.increment(ec)) {
+        auto status = it->status();
+        if(!status) {
+            continue;
         }
 
         // Skip hidden directories.
-        if(dir.filename().string().starts_with('.')) {
-            return false;
-        }
-
-        if(try_load(dir.string())) {
-            return true;
+        llvm::StringRef filename = path::filename(it->path());
+        if(fs::is_directory(*status) && filename.starts_with('.')) {
+            it.no_push();
+            continue;
         }
 
-        std::error_code ec;
-        for(const auto& entry: stdfs::directory_iterator(dir, ec)) {
-            if(ec) {
-                log::warn("Error iterating directory: {}, {}, skipped", dir.string(), ec.message());
-                continue;
-            }
-
-            if(self(entry.path())) {
-                return true;
+        if(fs::is_regular_file(*status) && filename == "compile_commands.json") {
+            if(try_load(it->path())) {
+                return;
             }
         }
-
-        return false;
-    };
-
-    if(recursive_search(workspace)) {
-        return;
     }
 
     /// TODO: Add a default command in clice.toml. Or load commands from .clangd ?

From ad309eb770a70959a91d0c6b62c4b981c4036394 Mon Sep 17 00:00:00 2001
From: Guo-Shiyu <im.shiyu1225@gmail.com>
Date: Fri, 29 Aug 2025 20:52:12 +0800
Subject: [PATCH 5/8] fix: store relative path of loaded source file in
 `CompilationDatabase`.

---
 include/Compiler/Command.h      |  6 +--
 src/Compiler/Command.cpp        | 59 +++++++++++++++------
 src/Server/Lifecycle.cpp        |  6 +--
 tests/unit/Compiler/Command.cpp | 94 +++++++++++++++++++++++++++++++++
 4 files changed, 144 insertions(+), 21 deletions(-)

diff --git a/include/Compiler/Command.h b/include/Compiler/Command.h
index 87c66d07..492c0e85 100644
--- a/include/Compiler/Command.h
+++ b/include/Compiler/Command.h
@@ -35,7 +35,7 @@ class CompilationDatabase {
 
     struct CommandInfo {
         /// TODO: add sysroot or no stdinc command info.
-        llvm::StringRef dictionary;
+        llvm::StringRef directory;
 
         /// The canonical command list.
         llvm::ArrayRef<const char*> arguments;
@@ -57,7 +57,7 @@ class CompilationDatabase {
     };
 
     struct LookupInfo {
-        llvm::StringRef dictionary;
+        llvm::StringRef directory;
 
         std::vector<const char*> arguments;
     };
@@ -106,7 +106,7 @@ class CompilationDatabase {
                         llvm::StringRef command) -> UpdateInfo;
 
     /// Update commands from json file and return all updated file.
-    auto load_commands(this Self& self, llvm::StringRef json_content)
+    auto load_commands(this Self& self, llvm::StringRef json_content, llvm::StringRef workspace)
         -> std::expected<std::vector<UpdateInfo>, std::string>;
 
     auto get_command(this Self& self, llvm::StringRef file, CommandOptions options = {})
diff --git a/src/Compiler/Command.cpp b/src/Compiler/Command.cpp
index 7866fb31..10c5a772 100644
--- a/src/Compiler/Command.cpp
+++ b/src/Compiler/Command.cpp
@@ -257,11 +257,11 @@ auto CompilationDatabase::query_driver(this Self& self, llvm::StringRef driver)
 }
 
 auto CompilationDatabase::update_command(this Self& self,
-                                         llvm::StringRef dictionary,
+                                         llvm::StringRef directory,
                                          llvm::StringRef file,
                                          llvm::ArrayRef<const char*> arguments) -> UpdateInfo {
     file = self.save_string(file);
-    dictionary = self.save_string(dictionary);
+    directory = self.save_string(directory);
 
     llvm::SmallVector<const char*, 16> filtered_arguments;
 
@@ -293,6 +293,21 @@ auto CompilationDatabase::update_command(this Self& self,
             continue;
         }
 
+        /// For arguments -I<dir>, convert directory to absolute path.
+        /// i.e xmake will generate commands in this style.
+        if(id == clang::driver::options::OPT_I) {
+            if(arg->getNumValues() == 1) {
+                add_argument("-I");
+                llvm::StringRef value = arg->getValue(0);
+                if(!value.empty() && !path::is_absolute(value)) {
+                    add_argument(path::join(directory, value));
+                } else {
+                    add_argument(value);
+                }
+            }
+            continue;
+        }
+
         /// A workaround to remove extra PCH when cmake
         /// generate PCH flags for clang.
         if(id == clang::driver::options::OPT_Xclang) {
@@ -355,16 +370,15 @@ auto CompilationDatabase::update_command(this Self& self,
     arguments = self.save_cstring_list(filtered_arguments);
 
     UpdateKind kind = UpdateKind::Unchange;
-    CommandInfo info = {dictionary, arguments};
+    CommandInfo info = {directory, arguments};
     auto [it, success] = self.command_infos.try_emplace(file.data(), info);
     if(success) {
         kind = UpdateKind::Create;
     } else {
         auto& info = it->second;
-        if(info.dictionary.data() != dictionary.data() ||
-           info.arguments.data() != arguments.data()) {
+        if(info.directory.data() != directory.data() || info.arguments.data() != arguments.data()) {
             kind = UpdateKind::Update;
-            info.dictionary = dictionary;
+            info.directory = directory;
             info.arguments = arguments;
         }
     }
@@ -373,7 +387,7 @@ auto CompilationDatabase::update_command(this Self& self,
 }
 
 auto CompilationDatabase::update_command(this Self& self,
-                                         llvm::StringRef dictionary,
+                                         llvm::StringRef directory,
                                          llvm::StringRef file,
                                          llvm::StringRef command) -> UpdateInfo {
     llvm::BumpPtrAllocator local;
@@ -390,10 +404,12 @@ auto CompilationDatabase::update_command(this Self& self,
         llvm::cl::TokenizeGNUCommandLine(command, saver, arguments);
     }
 
-    return self.update_command(dictionary, file, arguments);
+    return self.update_command(directory, file, arguments);
 }
 
-auto CompilationDatabase::load_commands(this Self& self, llvm::StringRef json_content)
+auto CompilationDatabase::load_commands(this Self& self,
+                                        llvm::StringRef json_content,
+                                        llvm::StringRef workspace)
     -> std::expected<std::vector<UpdateInfo>, std::string> {
     std::vector<UpdateInfo> infos;
 
@@ -415,9 +431,22 @@ auto CompilationDatabase::load_commands(this Self& self, llvm::StringRef json_co
 
         auto& object = *item.getAsObject();
 
-        auto file = object.getString("file");
         auto directory = object.getString("directory");
-        if(!file || !directory) {
+        if(!directory) {
+            continue;
+        }
+
+        /// Always store relative path of source file.
+        std::string source;
+        if(auto file = object.getString("file")) {
+            if(path::is_absolute(*file)) {
+                llvm::SmallString<256> buffer = *file;
+                path::replace_path_prefix(buffer, workspace, "");
+                source = path::relative_path(buffer).str();
+            } else {
+                source = file->str();
+            }
+        } else {
             continue;
         }
 
@@ -433,12 +462,12 @@ auto CompilationDatabase::load_commands(this Self& self, llvm::StringRef json_co
                 }
             }
 
-            auto info = self.update_command(*directory, *file, carguments);
+            auto info = self.update_command(*directory, source, carguments);
             if(info.kind != UpdateKind::Unchange) {
                 infos.emplace_back(info);
             }
         } else if(auto command = object.getString("command")) {
-            auto info = self.update_command(*directory, *file, *command);
+            auto info = self.update_command(*directory, source, *command);
             if(info.kind != UpdateKind::Unchange) {
                 infos.emplace_back(info);
             }
@@ -455,7 +484,7 @@ auto CompilationDatabase::get_command(this Self& self, llvm::StringRef file, Com
     file = self.save_string(file);
     auto it = self.command_infos.find(file.data());
     if(it != self.command_infos.end()) {
-        info.dictionary = it->second.dictionary;
+        info.directory = it->second.directory;
         info.arguments = it->second.arguments;
     } else {
         info = self.guess_or_fallback(file);
@@ -502,7 +531,7 @@ auto CompilationDatabase::guess_or_fallback(this Self& self, llvm::StringRef fil
         for(const auto& [other_file, info]: self.command_infos) {
             if(llvm::StringRef other = other_file; other.starts_with(dir)) {
                 log::info("Guess command for:{}, from existed file: {}", file, other_file);
-                return LookupInfo{info.dictionary, info.arguments};
+                return LookupInfo{info.directory, info.arguments};
             }
         }
         dir = path::parent_path(dir);
diff --git a/src/Server/Lifecycle.cpp b/src/Server/Lifecycle.cpp
index aacc79c5..a7feb3bc 100644
--- a/src/Server/Lifecycle.cpp
+++ b/src/Server/Lifecycle.cpp
@@ -8,9 +8,9 @@ namespace {
 /// search recursively from the workspace directory.
 void load_compile_commands(CompilationDatabase& database,
                            const std::vector<std::string>& compile_commands_dirs,
-                           const std::string& workspace) {
+                           llvm::StringRef workspace) {
 
-    auto try_load = [&database](const std::string& dir) {
+    auto try_load = [&database, workspace](const std::string& dir) {
         std::string filepath = path::join(dir, "compile_commands.json");
         auto content = fs::read(filepath);
         if(!content) {
@@ -18,7 +18,7 @@ void load_compile_commands(CompilationDatabase& database,
             return false;
         }
 
-        auto load = database.load_commands(*content);
+        auto load = database.load_commands(*content, workspace);
         if(!load) {
             log::warn("Failed to load CDB file: {}. {}", filepath, load.error());
             return false;
diff --git a/tests/unit/Compiler/Command.cpp b/tests/unit/Compiler/Command.cpp
index 828b0c38..f14efefb 100644
--- a/tests/unit/Compiler/Command.cpp
+++ b/tests/unit/Compiler/Command.cpp
@@ -216,6 +216,100 @@ suite<"Command"> command = [] {
         /// expect(that % command[2] == "test.cpp"sv);
         /// expect(that % command[3] == std::format("-resource-dir={}", fs::resource_dir));
     };
+
+    auto expect_load = [](llvm::StringRef content,
+                          llvm::StringRef workspace,
+                          llvm::StringRef file,
+                          llvm::StringRef directory,
+                          llvm::ArrayRef<const char*> arguments) {
+        CompilationDatabase database;
+        auto loaded = database.load_commands(content, workspace);
+        expect(that % loaded.has_value());
+
+        CommandOptions options;
+        options.query_driver = false;
+        options.resource_dir = false;
+        options.suppress_log = true;
+        auto info = database.get_command(file, options);
+
+        expect(that % info.directory == directory);
+        expect(that % info.arguments.size() == arguments.size());
+        for(size_t i = 0; i < arguments.size(); i++) {
+            llvm::StringRef arg = info.arguments[i];
+            llvm::StringRef expect_arg = arguments[i];
+            expect(that % arg == expect_arg);
+        }
+    };
+
+    test("LoadAbsoluteStyle") = [expect_load] {
+        constexpr const char* cmake = R"([
+        {
+            "directory": "/home/developer/clice/build",
+            "command": "/usr/bin/c++ -I/home/developer/clice/include -I/home/developer/clice/build/_deps/libuv-src/include -isystem /home/developer/clice/build/_deps/tomlplusplus-src/include -std=gnu++23 -fno-rtti -fno-exceptions -Wno-deprecated-declarations -Wno-undefined-inline -O3 -o CMakeFiles/clice-core.dir/src/Driver/clice.cpp.o -c /home/developer/clice/src/Driver/clice.cpp",
+            "file": "/home/developer/clice/src/Driver/clice.cpp",
+            "output": "CMakeFiles/clice-core.dir/src/Driver/clice.cpp.o"
+        }
+        ])";
+
+        expect_load(cmake,
+                    "/home/developer/clice",
+                    "src/Driver/clice.cpp",
+                    "/home/developer/clice/build",
+                    {
+                        "/usr/bin/c++",
+                        "-I",
+                        "/home/developer/clice/include",
+                        "-I",
+                        "/home/developer/clice/build/_deps/libuv-src/include",
+                        "-isystem",
+                        "/home/developer/clice/build/_deps/tomlplusplus-src/include",
+                        "-std=gnu++23",
+                        "-fno-rtti",
+                        "-fno-exceptions",
+                        "-Wno-deprecated-declarations",
+                        "-Wno-undefined-inline",
+                        "-O3",
+                        "src/Driver/clice.cpp",
+                    });
+    };
+
+    test("LoadRelativeStyle") = [expect_load] {
+        constexpr const char* xmake = R"([
+        {
+            "directory": "/home/developer/clice",
+            "arguments": ["/usr/bin/clang", "-c", "-Qunused-arguments", "-m64", "-g", "-O0", "-std=c++23", "-Iinclude", "-I/home/developer/clice/include", "-fno-exceptions", "-fno-cxx-exceptions", "-isystem", "/home/developer/.xmake/packages/l/libuv/v1.51.0/3ca1562e6c5d485f9ccafec8e0c50b6f/include", "-isystem", "/home/developer/.xmake/packages/t/toml++/v3.4.0/bde7344d843e41928b1d325fe55450e0/include", "-fsanitize=address", "-fno-rtti", "-o", "build/.objs/clice/linux/x86_64/debug/src/Driver/clice.cc.o", "src/Driver/clice.cc"],
+            "file": "src/Driver/clice.cc"
+        }
+        ])";
+
+        expect_load(
+            xmake,
+            "/home/developer/clice",
+            "src/Driver/clice.cc",
+            "/home/developer/clice",
+            {
+                "/usr/bin/clang",
+                "-Qunused-arguments",
+                "-m64",
+                "-g",
+                "-O0",
+                "-std=c++23",
+                //  parameter "-Iinclude" in CDB, should be convert to absolute path
+                "-I",
+                "/home/developer/clice/include",
+                "-I",
+                "/home/developer/clice/include",
+                "-fno-exceptions",
+                "-fno-cxx-exceptions",
+                "-isystem",
+                "/home/developer/.xmake/packages/l/libuv/v1.51.0/3ca1562e6c5d485f9ccafec8e0c50b6f/include",
+                "-isystem",
+                "/home/developer/.xmake/packages/t/toml++/v3.4.0/bde7344d843e41928b1d325fe55450e0/include",
+                "-fsanitize=address",
+                "-fno-rtti",
+                "src/Driver/clice.cc",
+            });
+    };
 };
 
 }  // namespace

From e2c279bef4b19476c5fa4f0904e05bcc3e210ff1 Mon Sep 17 00:00:00 2001
From: Guo-Shiyu <im.shiyu1225@gmail.com>
Date: Fri, 29 Aug 2025 21:16:38 +0800
Subject: [PATCH 6/8] Chore: fix test case on Windows.

---
 include/Compiler/Command.h      | 1 +
 tests/unit/Compiler/Command.cpp | 9 +++++----
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/Compiler/Command.h b/include/Compiler/Command.h
index 492c0e85..8665ec54 100644
--- a/include/Compiler/Command.h
+++ b/include/Compiler/Command.h
@@ -109,6 +109,7 @@ class CompilationDatabase {
     auto load_commands(this Self& self, llvm::StringRef json_content, llvm::StringRef workspace)
         -> std::expected<std::vector<UpdateInfo>, std::string>;
 
+    /// Get compile command from database. `file` should has relative path of workspace.
     auto get_command(this Self& self, llvm::StringRef file, CommandOptions options = {})
         -> LookupInfo;
 
diff --git a/tests/unit/Compiler/Command.cpp b/tests/unit/Compiler/Command.cpp
index f14efefb..952ee5b5 100644
--- a/tests/unit/Compiler/Command.cpp
+++ b/tests/unit/Compiler/Command.cpp
@@ -227,8 +227,6 @@ suite<"Command"> command = [] {
         expect(that % loaded.has_value());
 
         CommandOptions options;
-        options.query_driver = false;
-        options.resource_dir = false;
         options.suppress_log = true;
         auto info = database.get_command(file, options);
 
@@ -241,7 +239,9 @@ suite<"Command"> command = [] {
         }
     };
 
-    test("LoadAbsoluteStyle") = [expect_load] {
+#if defined(__unix__) || defined(__APPLE__)
+    /// TODO: add windows path testcase
+    test("LoadAbsoluteUnixStyle") = [expect_load] {
         constexpr const char* cmake = R"([
         {
             "directory": "/home/developer/clice/build",
@@ -273,7 +273,7 @@ suite<"Command"> command = [] {
                     });
     };
 
-    test("LoadRelativeStyle") = [expect_load] {
+    test("LoadRelativeUnixStyle") = [expect_load] {
         constexpr const char* xmake = R"([
         {
             "directory": "/home/developer/clice",
@@ -310,6 +310,7 @@ suite<"Command"> command = [] {
                 "src/Driver/clice.cc",
             });
     };
+#endif
 };
 
 }  // namespace

From a029a8b9cd8fadc219b8c715e15203d4f0137afd Mon Sep 17 00:00:00 2001
From: Guo-Shiyu <im.shiyu1225@gmail.com>
Date: Fri, 29 Aug 2025 21:58:23 +0800
Subject: [PATCH 7/8] Fix: fix by gemini suggestions.

---
 src/Compiler/Command.cpp | 5 ++++-
 src/Server/Lifecycle.cpp | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/Compiler/Command.cpp b/src/Compiler/Command.cpp
index 10c5a772..142eb4a4 100644
--- a/src/Compiler/Command.cpp
+++ b/src/Compiler/Command.cpp
@@ -529,7 +529,10 @@ auto CompilationDatabase::guess_or_fallback(this Self& self, llvm::StringRef fil
     while(!dir.empty() && up_level < 3) {
         // If any file in the directory has a command, use that command
         for(const auto& [other_file, info]: self.command_infos) {
-            if(llvm::StringRef other = other_file; other.starts_with(dir)) {
+            llvm::StringRef other = other_file;
+            // Filter case that dir is /path/to/foo and there's another directory /path/to/foobar
+            if(other.starts_with(dir) &&
+               (other.size() == dir.size() || path::is_separator(other[dir.size()]))) {
                 log::info("Guess command for:{}, from existed file: {}", file, other_file);
                 return LookupInfo{info.directory, info.arguments};
             }
diff --git a/src/Server/Lifecycle.cpp b/src/Server/Lifecycle.cpp
index a7feb3bc..f3f5cd90 100644
--- a/src/Server/Lifecycle.cpp
+++ b/src/Server/Lifecycle.cpp
@@ -10,7 +10,7 @@ void load_compile_commands(CompilationDatabase& database,
                            const std::vector<std::string>& compile_commands_dirs,
                            llvm::StringRef workspace) {
 
-    auto try_load = [&database, workspace](const std::string& dir) {
+    auto try_load = [&database, workspace](llvm::StringRef dir) {
         std::string filepath = path::join(dir, "compile_commands.json");
         auto content = fs::read(filepath);
         if(!content) {
@@ -52,7 +52,7 @@ void load_compile_commands(CompilationDatabase& database,
         }
 
         if(fs::is_regular_file(*status) && filename == "compile_commands.json") {
-            if(try_load(it->path())) {
+            if(try_load(path::parent_path(it->path()))) {
                 return;
             }
         }

From 5f47ab67407ac166aceb67482f03d2b5ce1f1783 Mon Sep 17 00:00:00 2001
From: Guo-Shiyu <im.shiyu1225@gmail.com>
Date: Tue, 2 Sep 2025 13:30:58 +0800
Subject: [PATCH 8/8] Chore: move `load_compile_commands()` to
 `CompilationDatabase` method.

---
 include/Compiler/Command.h |  6 ++++
 src/Compiler/Command.cpp   | 55 ++++++++++++++++++++++++++++++++
 src/Server/Lifecycle.cpp   | 64 +-------------------------------------
 3 files changed, 62 insertions(+), 63 deletions(-)

diff --git a/include/Compiler/Command.h b/include/Compiler/Command.h
index 8665ec54..6f0391e5 100644
--- a/include/Compiler/Command.h
+++ b/include/Compiler/Command.h
@@ -113,6 +113,12 @@ class CompilationDatabase {
     auto get_command(this Self& self, llvm::StringRef file, CommandOptions options = {})
         -> LookupInfo;
 
+    /// Load compile commands from given directories. If no valid commands are found,
+    /// search recursively from the workspace directory.
+    auto load_compile_commands(this Self& self,
+                               llvm::ArrayRef<std::string> compile_commands_dirs,
+                               llvm::StringRef workspace) -> void;
+
 private:
     /// If file not found in CDB file, try to guess commands or use the default case.
     auto guess_or_fallback(this Self& self, llvm::StringRef file) -> LookupInfo;
diff --git a/src/Compiler/Command.cpp b/src/Compiler/Command.cpp
index 142eb4a4..1c3d2b73 100644
--- a/src/Compiler/Command.cpp
+++ b/src/Compiler/Command.cpp
@@ -551,4 +551,59 @@ auto CompilationDatabase::guess_or_fallback(this Self& self, llvm::StringRef fil
     return info;
 }
 
+auto CompilationDatabase::load_compile_commands(this Self& self,
+                                                llvm::ArrayRef<std::string> compile_commands_dirs,
+                                                llvm::StringRef workspace) -> void {
+    auto try_load = [&self, workspace](llvm::StringRef dir) {
+        std::string filepath = path::join(dir, "compile_commands.json");
+        auto content = fs::read(filepath);
+        if(!content) {
+            log::warn("Failed to read CDB file: {}, {}", filepath, content.error());
+            return false;
+        }
+
+        auto load = self.load_commands(*content, workspace);
+        if(!load) {
+            log::warn("Failed to load CDB file: {}. {}", filepath, load.error());
+            return false;
+        }
+
+        log::info("Load CDB file: {} successfully, {} items loaded", filepath, load->size());
+        return true;
+    };
+
+    if(std::ranges::any_of(compile_commands_dirs, try_load)) {
+        return;
+    }
+
+    log::info(
+        "Can not found any valid CDB file from given directories, search recursively from workspace: {} ...",
+        workspace);
+
+    std::error_code ec;
+    for(fs::recursive_directory_iterator it(workspace, ec), end; it != end && !ec;
+        it.increment(ec)) {
+        auto status = it->status();
+        if(!status) {
+            continue;
+        }
+
+        // Skip hidden directories.
+        llvm::StringRef filename = path::filename(it->path());
+        if(fs::is_directory(*status) && filename.starts_with('.')) {
+            it.no_push();
+            continue;
+        }
+
+        if(fs::is_regular_file(*status) && filename == "compile_commands.json") {
+            if(try_load(path::parent_path(it->path()))) {
+                return;
+            }
+        }
+    }
+
+    /// TODO: Add a default command in clice.toml. Or load commands from .clangd ?
+    log::warn("Can not found any valid CDB file in current workspace, fallback to default mode.");
+}
+
 }  // namespace clice
diff --git a/src/Server/Lifecycle.cpp b/src/Server/Lifecycle.cpp
index 63004c69..bd5ac680 100644
--- a/src/Server/Lifecycle.cpp
+++ b/src/Server/Lifecycle.cpp
@@ -2,68 +2,6 @@
 
 namespace clice {
 
-namespace {
-
-/// Load compile commands from given directories. If no valid commands are found,
-/// search recursively from the workspace directory.
-void load_compile_commands(CompilationDatabase& database,
-                           const std::vector<std::string>& compile_commands_dirs,
-                           llvm::StringRef workspace) {
-
-    auto try_load = [&database, workspace](llvm::StringRef dir) {
-        std::string filepath = path::join(dir, "compile_commands.json");
-        auto content = fs::read(filepath);
-        if(!content) {
-            log::warn("Failed to read CDB file: {}, {}", filepath, content.error());
-            return false;
-        }
-
-        auto load = database.load_commands(*content, workspace);
-        if(!load) {
-            log::warn("Failed to load CDB file: {}. {}", filepath, load.error());
-            return false;
-        }
-
-        log::info("Load CDB file: {} successfully, {} items loaded", filepath, load->size());
-        return true;
-    };
-
-    if(std::ranges::any_of(compile_commands_dirs, try_load)) {
-        return;
-    }
-
-    log::info(
-        "Can not found any valid CDB file from given directories, search recursively from workspace: {} ...",
-        workspace);
-
-    std::error_code ec;
-    for(fs::recursive_directory_iterator it(workspace, ec), end; it != end && !ec;
-        it.increment(ec)) {
-        auto status = it->status();
-        if(!status) {
-            continue;
-        }
-
-        // Skip hidden directories.
-        llvm::StringRef filename = path::filename(it->path());
-        if(fs::is_directory(*status) && filename.starts_with('.')) {
-            it.no_push();
-            continue;
-        }
-
-        if(fs::is_regular_file(*status) && filename == "compile_commands.json") {
-            if(try_load(path::parent_path(it->path()))) {
-                return;
-            }
-        }
-    }
-
-    /// TODO: Add a default command in clice.toml. Or load commands from .clangd ?
-    log::warn("Can not found any valid CDB file in current workspace, fallback to default mode.");
-}
-
-}  // namespace
-
 async::Task<json::Value> Server::on_initialize(proto::InitializeParams params) {
     log::info("Initialize from client: {}, version: {}",
               params.clientInfo.name,
@@ -89,7 +27,7 @@ async::Task<json::Value> Server::on_initialize(proto::InitializeParams params) {
     opening_files.set_capability(config::server.max_active_file);
 
     /// Load compile commands.json
-    load_compile_commands(database, config::server.compile_commands_dirs, workspace);
+    database.load_compile_commands(config::server.compile_commands_dirs, workspace);
 
     /// Load cache info.
     load_cache_info();