From 21b4af305e198921cb82fcc57412f4b7fceb42dc Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Tue, 9 Dec 2025 15:48:28 +0300
Subject: [PATCH 01/17] add builtin

---
 .../stdlib/file/file-system-functions.h       | 46 ++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index 700d73f0f9..1680b0c92d 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -58,7 +58,7 @@ inline string f$basename(const string& path, const string& suffix = {}) noexcept
 }
 
 inline Optional<int64_t> f$filesize(const string& filename) noexcept {
-  struct stat stat {};
+  struct stat stat{};
   if (auto errc{k2::stat({filename.c_str(), filename.size()}, std::addressof(stat))}; errc != k2::errno_ok) [[unlikely]] {
     return false;
   }
@@ -197,3 +197,47 @@ inline Optional<string> f$file_get_contents(const string& stream) noexcept {
   }
   return false;
 }
+
+inline Optional<array<string>> f$file(const string& name) noexcept {
+  struct stat stat_buf;
+  uint64_t file_fd;
+
+  if (!k2::fopen(std::addressof(file_fd), name.c_str(), "r")) {
+    return false;
+  }
+  if (!k2::stat(name.c_str(), std::addressof(stat_buf))) {
+    k2::free_descriptor(file_fd);
+    return false;
+  }
+  if (!S_ISREG(stat_buf.st_mode)) {
+    k2::free_descriptor(file_fd);
+    kphp::log::warning("regular file expected as first argument in function file, \"{}\" is given", name.c_str());
+    return false;
+  }
+
+  const size_t size{static_cast<size_t>(stat_buf.st_size)};
+  if (size > string::max_size()) {
+    k2::free_descriptor(file_fd);
+    kphp::log::warning("file \"{}\" is too large", name.c_str());
+    return false;
+  }
+
+  string res(static_cast<string::size_type>(size), false);
+  char* s{res.buffer()};
+  if (k2::read(file_fd, size, s) < size) {
+    k2::free_descriptor(file_fd);
+    return false;
+  }
+  k2::free_descriptor(file_fd);
+
+  array<string> result;
+  int prev{-1};
+  for (size_t i = 0; i < size; i++) {
+    if (s[i] == '\n' || i + 1 == size) {
+      result.push_back(string(s + prev + 1, i - prev));
+      prev = i;
+    }
+  }
+
+  return result;
+}

From 7e05b177acae83dcad17e4d55879083fa9a1b8c2 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Tue, 9 Dec 2025 16:14:01 +0300
Subject: [PATCH 02/17] minorfix

---
 builtin-functions/kphp-light/stdlib/file-functions.txt | 5 ++---
 runtime-light/stdlib/file/file-system-functions.h      | 4 ++--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/builtin-functions/kphp-light/stdlib/file-functions.txt b/builtin-functions/kphp-light/stdlib/file-functions.txt
index 334aec33d2..5a8d6d89ff 100644
--- a/builtin-functions/kphp-light/stdlib/file-functions.txt
+++ b/builtin-functions/kphp-light/stdlib/file-functions.txt
@@ -40,8 +40,9 @@ function vsprintf ($format ::: string, $args ::: array) ::: string;
 
 function file_exists ($name ::: string) ::: bool;
 
-// === UNSUPPORTED ===
+function file ($name ::: string) ::: string[] | false;
 
+// === UNSUPPORTED ===
 /** @kphp-extern-func-info stub generation-required */
 function chmod ($name ::: string, $mode ::: int) ::: bool;
 /** @kphp-extern-func-info stub generation-required */
@@ -49,8 +50,6 @@ function copy ($from ::: string, $to ::: string) ::: bool;
 /** @kphp-extern-func-info stub generation-required */
 function dirname ($name ::: string) ::: string;
 /** @kphp-extern-func-info stub generation-required */
-function file ($name ::: string) ::: string[] | false;
-/** @kphp-extern-func-info stub generation-required */
 function file_put_contents ($name ::: string, $content ::: mixed, $flags ::: int = 0) ::: int | false;
 /** @kphp-extern-func-info stub generation-required */
 function filectime ($name ::: string) ::: int | false;
diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index 1680b0c92d..e0a6d45ad1 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -202,10 +202,10 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
   struct stat stat_buf;
   uint64_t file_fd;
 
-  if (!k2::fopen(std::addressof(file_fd), name.c_str(), "r")) {
+  if (k2::fopen(std::addressof(file_fd), name.c_str(), "r")) {
     return false;
   }
-  if (!k2::stat(name.c_str(), std::addressof(stat_buf))) {
+  if (k2::stat(name.c_str(), std::addressof(stat_buf))) {
     k2::free_descriptor(file_fd);
     return false;
   }

From 45624545cb402c6c0ce00723cba3020f9b3cf3d7 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Tue, 9 Dec 2025 16:16:08 +0300
Subject: [PATCH 03/17] minor fix

---
 runtime-light/stdlib/file/file-system-functions.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index e0a6d45ad1..26f8347dc7 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -58,7 +58,7 @@ inline string f$basename(const string& path, const string& suffix = {}) noexcept
 }
 
 inline Optional<int64_t> f$filesize(const string& filename) noexcept {
-  struct stat stat{};
+  struct stat stat {};
   if (auto errc{k2::stat({filename.c_str(), filename.size()}, std::addressof(stat))}; errc != k2::errno_ok) [[unlikely]] {
     return false;
   }

From b764b8dfab7341c2eaf78b3643461331d1483b79 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Tue, 9 Dec 2025 18:38:10 +0300
Subject: [PATCH 04/17] minifix

---
 runtime-light/stdlib/file/file-system-functions.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index 26f8347dc7..332bc5dd46 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -202,10 +202,10 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
   struct stat stat_buf;
   uint64_t file_fd;
 
-  if (k2::fopen(std::addressof(file_fd), name.c_str(), "r")) {
+  if (k2::fopen(std::addressof(file_fd), name.c_str(), "r") != k2::errno_ok) {
     return false;
   }
-  if (k2::stat(name.c_str(), std::addressof(stat_buf))) {
+  if (k2::stat(name.c_str(), std::addressof(stat_buf)) != k2::errno_ok) {
     k2::free_descriptor(file_fd);
     return false;
   }

From 6471b4a679a07e835f7d586e09e75e9af03240cc Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Wed, 10 Dec 2025 15:49:36 +0300
Subject: [PATCH 05/17] add is_file, add k2_lstat

---
 .../kphp-light/stdlib/file-functions.txt      |  4 ++--
 runtime-light/k2-platform/k2-api.h            |  7 ++++++
 runtime-light/k2-platform/k2-header.h         | 23 +++++++++++++++++++
 .../stdlib/file/file-system-functions.h       |  8 +++++++
 4 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/builtin-functions/kphp-light/stdlib/file-functions.txt b/builtin-functions/kphp-light/stdlib/file-functions.txt
index 5a8d6d89ff..e7398871ee 100644
--- a/builtin-functions/kphp-light/stdlib/file-functions.txt
+++ b/builtin-functions/kphp-light/stdlib/file-functions.txt
@@ -42,6 +42,8 @@ function file_exists ($name ::: string) ::: bool;
 
 function file ($name ::: string) ::: string[] | false;
 
+function is_file ($name ::: string) ::: bool;
+
 // === UNSUPPORTED ===
 /** @kphp-extern-func-info stub generation-required */
 function chmod ($name ::: string, $mode ::: int) ::: bool;
@@ -58,8 +60,6 @@ function filemtime ($name ::: string) ::: int | false;
 /** @kphp-extern-func-info stub generation-required */
 function is_dir ($name ::: string) ::: bool;
 /** @kphp-extern-func-info stub generation-required */
-function is_file ($name ::: string) ::: bool;
-/** @kphp-extern-func-info stub generation-required */
 function is_readable ($name ::: string) ::: bool;
 /** @kphp-extern-func-info stub generation-required */
 function mkdir ($name ::: string, $mode ::: int = 0777, $recursive ::: bool = false) ::: bool;
diff --git a/runtime-light/k2-platform/k2-api.h b/runtime-light/k2-platform/k2-api.h
index 95d189ae71..4ed2124ac6 100644
--- a/runtime-light/k2-platform/k2-api.h
+++ b/runtime-light/k2-platform/k2-api.h
@@ -418,6 +418,13 @@ inline int32_t stat(std::string_view path, struct stat* stat) noexcept {
   return k2::errno_ok;
 }
 
+inline int32_t lstat(std::string_view path, struct stat* stat) noexcept {
+  if (auto error_code{k2_lstat(path.data(), path.size(), stat)}; error_code != k2::errno_ok) [[unlikely]] {
+    return error_code;
+  }
+  return k2::errno_ok;
+}
+
 using CommandArg = CommandArg;
 
 enum class CommandStdoutPolicy : uint8_t { NoCapture, Capture };
diff --git a/runtime-light/k2-platform/k2-header.h b/runtime-light/k2-platform/k2-header.h
index 9a73d202f7..bb0bae3ee9 100644
--- a/runtime-light/k2-platform/k2-header.h
+++ b/runtime-light/k2-platform/k2-header.h
@@ -735,6 +735,29 @@ int32_t k2_canonicalize(const char* path, size_t pathlen, char* const* resolved_
  */
 int32_t k2_stat(const char* pathname, size_t pathname_len, struct stat* statbuf);
 
+  /**
+ * Semantically equivalent to libc's `lstat`.
+ *
+ * Possible `errno`:
+ * `EACCES` => Search permission is denied for one of the directories in the path prefix of `pathname`.
+ * `EINVAL` => `pathname` or `statbuf` is `NULL`.
+ * `EFAULT` => Bad address.
+ * `ELOOP` => Too many symbolic links encountered while traversing the path.
+ * `ENAMETOOLONG` => `pathname` is too long.
+ * `ENOENT` => A component of `pathname` does not exist or is a dangling symbolic link.
+ * `ENOMEM` => Out of memory (i.e., kernel memory).
+ * `ENOTDIR` => A component of the path prefix of `pathname` is not a directory.
+ * `EOVERFLOW` => `pathname` refers to a file whose size, inode number,
+ *                or number of blocks cannot be represented in, respectively,
+ *                the types `off_t`, `ino_t`, or `blkcnt_t`.  This error can occur
+ *                when, for example, an application compiled on a 32-bit
+ *                platform without `-D_FILE_OFFSET_BITS=64` calls `lstat()` on a
+ *                file whose size exceeds `(1<<31)-1` bytes.
+ * `ERANGE` => Failed to convert `st_size`, `st_blksize`, or `st_blocks` to `int64_t`.
+ * `ENOSYS` => Internal error.
+ */
+int32_t k2_lstat(const char* pathname, size_t pathname_len, struct stat* statbuf);
+
 struct CommandArg {
   const char* arg;
   size_t arg_len;
diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index 332bc5dd46..ea6e780c9e 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -241,3 +241,11 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
 
   return result;
 }
+
+inline bool f$is_file(const string& name) noexcept {
+  struct stat stat_buf;
+  if (k2::lstat(name.c_str(), &stat_buf) != k2::errno_ok) {
+    return false;
+  }
+  return S_ISREG(stat_buf.st_mode);
+}

From 3c97c797579de386265bb2142bc7ffaca1d864b2 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Wed, 10 Dec 2025 15:51:22 +0300
Subject: [PATCH 06/17] minor fix

---
 runtime-light/k2-platform/k2-header.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/runtime-light/k2-platform/k2-header.h b/runtime-light/k2-platform/k2-header.h
index bb0bae3ee9..e64067f360 100644
--- a/runtime-light/k2-platform/k2-header.h
+++ b/runtime-light/k2-platform/k2-header.h
@@ -735,7 +735,7 @@ int32_t k2_canonicalize(const char* path, size_t pathlen, char* const* resolved_
  */
 int32_t k2_stat(const char* pathname, size_t pathname_len, struct stat* statbuf);
 
-  /**
+/**
  * Semantically equivalent to libc's `lstat`.
  *
  * Possible `errno`:

From 879e148d05a3666a1e0d3d5cb43bf713eadf60fa Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Wed, 10 Dec 2025 15:56:26 +0300
Subject: [PATCH 07/17] minor fix

---
 runtime-light/stdlib/file/file-system-functions.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index ea6e780c9e..df3772d9e9 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -244,7 +244,7 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
 
 inline bool f$is_file(const string& name) noexcept {
   struct stat stat_buf;
-  if (k2::lstat(name.c_str(), &stat_buf) != k2::errno_ok) {
+  if (k2::lstat(name.c_str(), std::addressof(stat_buf)) != k2::errno_ok) {
     return false;
   }
   return S_ISREG(stat_buf.st_mode);

From e643a877a42ca0fe4ba51ccd0253b193376f20aa Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Thu, 11 Dec 2025 17:53:16 +0300
Subject: [PATCH 08/17] minor fix

---
 .../stdlib/file/file-system-functions.h       | 30 +++++++++----------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index df3772d9e9..ebca02ffcf 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -200,41 +200,41 @@ inline Optional<string> f$file_get_contents(const string& stream) noexcept {
 
 inline Optional<array<string>> f$file(const string& name) noexcept {
   struct stat stat_buf;
-  uint64_t file_fd;
 
-  if (k2::fopen(std::addressof(file_fd), name.c_str(), "r") != k2::errno_ok) {
+  auto open_res = kphp::fs::file::open(name.c_str(), "r");
+  if (!open_res.has_value()) {
     return false;
   }
+  auto& file = open_res.value();
+
   if (k2::stat(name.c_str(), std::addressof(stat_buf)) != k2::errno_ok) {
-    k2::free_descriptor(file_fd);
     return false;
   }
   if (!S_ISREG(stat_buf.st_mode)) {
-    k2::free_descriptor(file_fd);
     kphp::log::warning("regular file expected as first argument in function file, \"{}\" is given", name.c_str());
     return false;
   }
 
   const size_t size{static_cast<size_t>(stat_buf.st_size)};
   if (size > string::max_size()) {
-    k2::free_descriptor(file_fd);
     kphp::log::warning("file \"{}\" is too large", name.c_str());
     return false;
   }
 
-  string res(static_cast<string::size_type>(size), false);
-  char* s{res.buffer()};
-  if (k2::read(file_fd, size, s) < size) {
-    k2::free_descriptor(file_fd);
+  string res{static_cast<string::size_type>(size), false};
+  char* res_buffer{res.buffer()};
+  std::span<std::byte> spn{reinterpret_cast<std::byte*>(res_buffer), res.size()};
+  if (auto rd_status = file.read(spn); !rd_status.has_value() || rd_status.value() < size) {
     return false;
   }
-  k2::free_descriptor(file_fd);
+
+  file.close();
 
   array<string> result;
-  int prev{-1};
-  for (size_t i = 0; i < size; i++) {
-    if (s[i] == '\n' || i + 1 == size) {
-      result.push_back(string(s + prev + 1, i - prev));
+  int32_t prev{-1};
+  for (size_t i{0}; i < size; i++) {
+    if (res_buffer[i] == '\n' || i + 1 == size) {
+      result.push_back(string(res_buffer + prev + 1, i - prev));
       prev = i;
     }
   }
@@ -243,7 +243,7 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
 }
 
 inline bool f$is_file(const string& name) noexcept {
-  struct stat stat_buf;
+  struct stat stat_buf {};
   if (k2::lstat(name.c_str(), std::addressof(stat_buf)) != k2::errno_ok) {
     return false;
   }

From 411abdc7048f8306808be6d2af7afc844d144724 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Fri, 12 Dec 2025 15:09:11 +0300
Subject: [PATCH 09/17] fixes

---
 runtime-light/k2-platform/k2-api.h            | 12 ++++----
 runtime-light/state/component-state.cpp       |  5 ++--
 .../stdlib/file/file-system-functions.h       | 30 ++++++++++---------
 runtime-light/stdlib/kml/kml-file-api.h       |  4 +--
 runtime/files.cpp                             |  1 +
 5 files changed, 28 insertions(+), 24 deletions(-)

diff --git a/runtime-light/k2-platform/k2-api.h b/runtime-light/k2-platform/k2-api.h
index 4ed2124ac6..0fc134d7f2 100644
--- a/runtime-light/k2-platform/k2-api.h
+++ b/runtime-light/k2-platform/k2-api.h
@@ -411,18 +411,18 @@ inline auto canonicalize(std::string_view path) noexcept {
   return return_type{{unique_ptr_type{resolved_path, std::invoke(deleter_creator, resolved_path_len, resolved_path_align)}, resolved_path_len}};
 }
 
-inline int32_t stat(std::string_view path, struct stat* stat) noexcept {
+inline std::expected<void, int32_t> stat(std::string_view path, struct stat* stat) noexcept {
   if (auto error_code{k2_stat(path.data(), path.size(), stat)}; error_code != k2::errno_ok) [[unlikely]] {
-    return error_code;
+    return std::unexpected{error_code};
   }
-  return k2::errno_ok;
+  return {};
 }
 
-inline int32_t lstat(std::string_view path, struct stat* stat) noexcept {
+inline std::expected<void, int32_t> lstat(std::string_view path, struct stat* stat) noexcept {
   if (auto error_code{k2_lstat(path.data(), path.size(), stat)}; error_code != k2::errno_ok) [[unlikely]] {
-    return error_code;
+    return std::unexpected{error_code};
   }
-  return k2::errno_ok;
+  return {};
 }
 
 using CommandArg = CommandArg;
diff --git a/runtime-light/state/component-state.cpp b/runtime-light/state/component-state.cpp
index 62e8bd93db..7c94afbbab 100644
--- a/runtime-light/state/component-state.cpp
+++ b/runtime-light/state/component-state.cpp
@@ -86,8 +86,9 @@ void ComponentState::parse_runtime_config_arg(std::string_view value_view) noexc
   }
 
   struct stat stat {};
-  if (auto error_code{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; error_code != k2::errno_ok) [[unlikely]] {
-    return kphp::log::warning("error getting runtime-config stat: error code -> {}", error_code);
+  if (auto error_code_expected{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; !error_code_expected.has_value())
+      [[unlikely]] {
+    return kphp::log::warning("error getting runtime-config stat: error code -> {}", error_code_expected.error());
   }
 
   const auto runtime_config_mem{std::unique_ptr<char, decltype(std::addressof(kphp::memory::script::free))>{
diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index ebca02ffcf..dc8f90b553 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -16,7 +16,9 @@
 #include <unistd.h>
 #include <utility>
 
+#include "runtime-common/core/allocator/script-allocator.h"
 #include "runtime-common/core/runtime-core.h"
+#include "runtime-common/core/std/containers.h"
 #include "runtime-common/stdlib/string/string-functions.h"
 #include "runtime-light/coroutine/task.h"
 #include "runtime-light/k2-platform/k2-api.h"
@@ -59,7 +61,7 @@ inline string f$basename(const string& path, const string& suffix = {}) noexcept
 
 inline Optional<int64_t> f$filesize(const string& filename) noexcept {
   struct stat stat {};
-  if (auto errc{k2::stat({filename.c_str(), filename.size()}, std::addressof(stat))}; errc != k2::errno_ok) [[unlikely]] {
+  if (auto errc_expected{k2::stat({filename.c_str(), filename.size()}, std::addressof(stat))}; !errc_expected.has_value()) [[unlikely]] {
     return false;
   }
   return static_cast<int64_t>(stat.st_size);
@@ -199,15 +201,13 @@ inline Optional<string> f$file_get_contents(const string& stream) noexcept {
 }
 
 inline Optional<array<string>> f$file(const string& name) noexcept {
-  struct stat stat_buf;
+  struct stat stat_buf {};
 
-  auto open_res = kphp::fs::file::open(name.c_str(), "r");
-  if (!open_res.has_value()) {
+  auto open_result{kphp::fs::file::open(name.c_str(), "r")};
+  if (!open_result.has_value()) {
     return false;
   }
-  auto& file = open_res.value();
-
-  if (k2::stat(name.c_str(), std::addressof(stat_buf)) != k2::errno_ok) {
+  if (!k2::stat(name.c_str(), std::addressof(stat_buf)).has_value()) {
     return false;
   }
   if (!S_ISREG(stat_buf.st_mode)) {
@@ -221,10 +221,12 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
     return false;
   }
 
-  string res{static_cast<string::size_type>(size), false};
-  char* res_buffer{res.buffer()};
-  std::span<std::byte> spn{reinterpret_cast<std::byte*>(res_buffer), res.size()};
-  if (auto rd_status = file.read(spn); !rd_status.has_value() || rd_status.value() < size) {
+  auto& file{open_result.value()};
+
+  kphp::stl::vector<char, kphp::memory::script_allocator> read_result(size);
+  char* read_result_data{read_result.data()};
+  std::span<std::byte> temp_span{reinterpret_cast<std::byte*>(read_result_data), read_result.size()};
+  if (auto rd_status{file.read(temp_span)}; !rd_status.has_value() || rd_status.value() < size) {
     return false;
   }
 
@@ -233,8 +235,8 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
   array<string> result;
   int32_t prev{-1};
   for (size_t i{0}; i < size; i++) {
-    if (res_buffer[i] == '\n' || i + 1 == size) {
-      result.push_back(string(res_buffer + prev + 1, i - prev));
+    if (read_result_data[i] == '\n' || i + 1 == size) {
+      result.push_back(string{read_result_data + prev + 1, static_cast<string::size_type>(i - prev)});
       prev = i;
     }
   }
@@ -244,7 +246,7 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
 
 inline bool f$is_file(const string& name) noexcept {
   struct stat stat_buf {};
-  if (k2::lstat(name.c_str(), std::addressof(stat_buf)) != k2::errno_ok) {
+  if (!k2::lstat(name.c_str(), std::addressof(stat_buf)).has_value()) {
     return false;
   }
   return S_ISREG(stat_buf.st_mode);
diff --git a/runtime-light/stdlib/kml/kml-file-api.h b/runtime-light/stdlib/kml/kml-file-api.h
index 7606fe36be..394adbda92 100644
--- a/runtime-light/stdlib/kml/kml-file-api.h
+++ b/runtime-light/stdlib/kml/kml-file-api.h
@@ -120,8 +120,8 @@ class dir_traverser final : public kphp::kml::dir_traverser_interface<dir_traver
     }
 
     struct stat stat {};
-    if (auto error_code{k2::stat(direntry_path, std::addressof(stat))}; error_code != k2::errno_ok) [[unlikely]] {
-      kphp::log::warning("[kml] failed to get stat: error code -> {}, path -> {}", error_code, direntry_path);
+    if (auto error_code_expected{k2::stat(direntry_path, std::addressof(stat))}; !error_code_expected.has_value()) [[unlikely]] {
+      kphp::log::warning("[kml] failed to get stat: error code -> {}, path -> {}", error_code_expected.error(), direntry_path);
       return std::nullopt;
     }
 
diff --git a/runtime/files.cpp b/runtime/files.cpp
index 781ef78ccf..25d13374eb 100644
--- a/runtime/files.cpp
+++ b/runtime/files.cpp
@@ -313,6 +313,7 @@ bool f$is_dir(const string& name) {
 bool f$is_file(const string& name) {
   struct stat stat_buf;
   dl::enter_critical_section(); // OK
+  // TODO: the semantics in PHP are different
   if (lstat(name.c_str(), &stat_buf) < 0) {
     dl::leave_critical_section();
     return false;

From 3005e5018e9227abd3ac84f62aed933404422593 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Mon, 15 Dec 2025 14:35:07 +0300
Subject: [PATCH 10/17] minor fix

---
 runtime-light/stdlib/file/file-system-functions.h | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index dc8f90b553..bf349ccd70 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -223,10 +223,8 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
 
   auto& file{open_result.value()};
 
-  kphp::stl::vector<char, kphp::memory::script_allocator> read_result(size);
-  char* read_result_data{read_result.data()};
-  std::span<std::byte> temp_span{reinterpret_cast<std::byte*>(read_result_data), read_result.size()};
-  if (auto rd_status{file.read(temp_span)}; !rd_status.has_value() || rd_status.value() < size) {
+  kphp::stl::vector<std::byte, kphp::memory::script_allocator> read_result(size);
+  if (auto rd_status{file.read(read_result)}; !rd_status.has_value() || rd_status.value() < size) {
     return false;
   }
 
@@ -235,8 +233,8 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
   array<string> result;
   int32_t prev{-1};
   for (size_t i{0}; i < size; i++) {
-    if (read_result_data[i] == '\n' || i + 1 == size) {
-      result.push_back(string{read_result_data + prev + 1, static_cast<string::size_type>(i - prev)});
+    if (static_cast<char>(read_result[i]) == '\n' || i + 1 == size) {
+      result.push_back(string{reinterpret_cast<char*>(read_result.data()) + prev + 1, static_cast<string::size_type>(i - prev)});
       prev = i;
     }
   }

From 4cd91d636c9a0b18a0828f5d9f61432ae32fedf1 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Mon, 15 Dec 2025 14:39:08 +0300
Subject: [PATCH 11/17] minor fix

---
 runtime-light/stdlib/file/file-system-functions.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index bf349ccd70..a3e7c61ec1 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -223,7 +223,7 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
 
   auto& file{open_result.value()};
 
-  kphp::stl::vector<std::byte, kphp::memory::script_allocator> read_result(size);
+  kphp::stl::vector<std::byte, kphp::memory::script_allocator> read_result{size};
   if (auto rd_status{file.read(read_result)}; !rd_status.has_value() || rd_status.value() < size) {
     return false;
   }

From 9eb5da7aae75d0d5696555c4929bb1707412c832 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Mon, 15 Dec 2025 16:10:56 +0300
Subject: [PATCH 12/17] minor fix

---
 runtime-light/state/component-state.cpp           | 4 ++--
 runtime-light/stdlib/file/file-system-functions.h | 3 ++-
 runtime-light/stdlib/kml/kml-file-api.h           | 4 ++--
 runtime/files.cpp                                 | 1 -
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/runtime-light/state/component-state.cpp b/runtime-light/state/component-state.cpp
index 7c94afbbab..d0b49a9795 100644
--- a/runtime-light/state/component-state.cpp
+++ b/runtime-light/state/component-state.cpp
@@ -86,9 +86,9 @@ void ComponentState::parse_runtime_config_arg(std::string_view value_view) noexc
   }
 
   struct stat stat {};
-  if (auto error_code_expected{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; !error_code_expected.has_value())
+  if (auto stat_result{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; !stat_result.has_value())
       [[unlikely]] {
-    return kphp::log::warning("error getting runtime-config stat: error code -> {}", error_code_expected.error());
+    return kphp::log::warning("error getting runtime-config stat: error code -> {}", stat_result.error());
   }
 
   const auto runtime_config_mem{std::unique_ptr<char, decltype(std::addressof(kphp::memory::script::free))>{
diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index a3e7c61ec1..eed8561c77 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -61,7 +61,7 @@ inline string f$basename(const string& path, const string& suffix = {}) noexcept
 
 inline Optional<int64_t> f$filesize(const string& filename) noexcept {
   struct stat stat {};
-  if (auto errc_expected{k2::stat({filename.c_str(), filename.size()}, std::addressof(stat))}; !errc_expected.has_value()) [[unlikely]] {
+  if (auto stat_result{k2::stat({filename.c_str(), filename.size()}, std::addressof(stat))}; !stat_result.has_value()) [[unlikely]] {
     return false;
   }
   return static_cast<int64_t>(stat.st_size);
@@ -244,6 +244,7 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
 
 inline bool f$is_file(const string& name) noexcept {
   struct stat stat_buf {};
+  // TODO: the semantics in PHP are different: PHP expects stat
   if (!k2::lstat(name.c_str(), std::addressof(stat_buf)).has_value()) {
     return false;
   }
diff --git a/runtime-light/stdlib/kml/kml-file-api.h b/runtime-light/stdlib/kml/kml-file-api.h
index 394adbda92..3d6f78ccf8 100644
--- a/runtime-light/stdlib/kml/kml-file-api.h
+++ b/runtime-light/stdlib/kml/kml-file-api.h
@@ -120,8 +120,8 @@ class dir_traverser final : public kphp::kml::dir_traverser_interface<dir_traver
     }
 
     struct stat stat {};
-    if (auto error_code_expected{k2::stat(direntry_path, std::addressof(stat))}; !error_code_expected.has_value()) [[unlikely]] {
-      kphp::log::warning("[kml] failed to get stat: error code -> {}, path -> {}", error_code_expected.error(), direntry_path);
+    if (auto stat_result{k2::stat(direntry_path, std::addressof(stat))}; !stat_result.has_value()) [[unlikely]] {
+      kphp::log::warning("[kml] failed to get stat: error code -> {}, path -> {}", stat_result.error(), direntry_path);
       return std::nullopt;
     }
 
diff --git a/runtime/files.cpp b/runtime/files.cpp
index 25d13374eb..781ef78ccf 100644
--- a/runtime/files.cpp
+++ b/runtime/files.cpp
@@ -313,7 +313,6 @@ bool f$is_dir(const string& name) {
 bool f$is_file(const string& name) {
   struct stat stat_buf;
   dl::enter_critical_section(); // OK
-  // TODO: the semantics in PHP are different
   if (lstat(name.c_str(), &stat_buf) < 0) {
     dl::leave_critical_section();
     return false;

From 6e67c47690f33ecae30aadf6c979e4877c84d227 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Mon, 15 Dec 2025 16:12:09 +0300
Subject: [PATCH 13/17] minor fix

---
 runtime-light/state/component-state.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/runtime-light/state/component-state.cpp b/runtime-light/state/component-state.cpp
index d0b49a9795..ec8983b873 100644
--- a/runtime-light/state/component-state.cpp
+++ b/runtime-light/state/component-state.cpp
@@ -85,9 +85,8 @@ void ComponentState::parse_runtime_config_arg(std::string_view value_view) noexc
     return kphp::log::warning("error opening runtime-config: error code -> {}", expected_runtime_config_file.error());
   }
 
-  struct stat stat {};
-  if (auto stat_result{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; !stat_result.has_value())
-      [[unlikely]] {
+  struct stat stat{};
+  if (auto stat_result{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; !stat_result.has_value()) [[unlikely]] {
     return kphp::log::warning("error getting runtime-config stat: error code -> {}", stat_result.error());
   }
 

From 55ca8e7682a24ba5768e90709f3cd12431d8b1ef Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Mon, 15 Dec 2025 16:14:21 +0300
Subject: [PATCH 14/17] minor fix

---
 runtime-light/state/component-state.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/runtime-light/state/component-state.cpp b/runtime-light/state/component-state.cpp
index ec8983b873..e6a16746e1 100644
--- a/runtime-light/state/component-state.cpp
+++ b/runtime-light/state/component-state.cpp
@@ -85,7 +85,7 @@ void ComponentState::parse_runtime_config_arg(std::string_view value_view) noexc
     return kphp::log::warning("error opening runtime-config: error code -> {}", expected_runtime_config_file.error());
   }
 
-  struct stat stat{};
+  struct stat stat {};
   if (auto stat_result{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; !stat_result.has_value()) [[unlikely]] {
     return kphp::log::warning("error getting runtime-config stat: error code -> {}", stat_result.error());
   }

From 0dc3b6be7161931df0acd5194a20c29b64084d68 Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Mon, 15 Dec 2025 16:43:26 +0300
Subject: [PATCH 15/17] minor fix

---
 runtime-light/stdlib/file/file-system-functions.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index eed8561c77..f4ccc44aa4 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -223,8 +223,8 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
 
   auto& file{open_result.value()};
 
-  kphp::stl::vector<std::byte, kphp::memory::script_allocator> read_result{size};
-  if (auto rd_status{file.read(read_result)}; !rd_status.has_value() || rd_status.value() < size) {
+  kphp::stl::vector<std::byte, kphp::memory::script_allocator> file_content{size};
+  if (auto rd_status{file.read(file_content)}; !rd_status.has_value() || rd_status.value() < size) {
     return false;
   }
 
@@ -233,8 +233,8 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
   array<string> result;
   int32_t prev{-1};
   for (size_t i{0}; i < size; i++) {
-    if (static_cast<char>(read_result[i]) == '\n' || i + 1 == size) {
-      result.push_back(string{reinterpret_cast<char*>(read_result.data()) + prev + 1, static_cast<string::size_type>(i - prev)});
+    if (static_cast<char>(file_content[i]) == '\n' || i + 1 == size) {
+      result.push_back(string{reinterpret_cast<char*>(file_content.data()) + prev + 1, static_cast<string::size_type>(i - prev)});
       prev = i;
     }
   }

From e33310e1be23c9a7091f132b0efff61c355e629f Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Tue, 16 Dec 2025 16:10:46 +0300
Subject: [PATCH 16/17] minor fix

---
 runtime-light/state/component-state.cpp           |  5 +++--
 runtime-light/stdlib/file/file-system-functions.h | 15 +++++++--------
 runtime-light/stdlib/kml/kml-file-api.h           |  4 ++--
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/runtime-light/state/component-state.cpp b/runtime-light/state/component-state.cpp
index e6a16746e1..16981067fa 100644
--- a/runtime-light/state/component-state.cpp
+++ b/runtime-light/state/component-state.cpp
@@ -86,8 +86,9 @@ void ComponentState::parse_runtime_config_arg(std::string_view value_view) noexc
   }
 
   struct stat stat {};
-  if (auto stat_result{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; !stat_result.has_value()) [[unlikely]] {
-    return kphp::log::warning("error getting runtime-config stat: error code -> {}", stat_result.error());
+  if (auto expected_stat_result{k2::stat({runtime_config_path.get(), runtime_config_path_size}, std::addressof(stat))}; !expected_stat_result.has_value())
+      [[unlikely]] {
+    return kphp::log::warning("error getting runtime-config stat: error code -> {}", expected_stat_result.error());
   }
 
   const auto runtime_config_mem{std::unique_ptr<char, decltype(std::addressof(kphp::memory::script::free))>{
diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index f4ccc44aa4..ff7835491c 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -203,8 +203,8 @@ inline Optional<string> f$file_get_contents(const string& stream) noexcept {
 inline Optional<array<string>> f$file(const string& name) noexcept {
   struct stat stat_buf {};
 
-  auto open_result{kphp::fs::file::open(name.c_str(), "r")};
-  if (!open_result.has_value()) {
+  auto expected_file{kphp::fs::file::open(name.c_str(), "r")};
+  if (!expected_file.has_value()) {
     return false;
   }
   if (!k2::stat(name.c_str(), std::addressof(stat_buf)).has_value()) {
@@ -221,15 +221,14 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
     return false;
   }
 
-  auto& file{open_result.value()};
-
   kphp::stl::vector<std::byte, kphp::memory::script_allocator> file_content{size};
-  if (auto rd_status{file.read(file_content)}; !rd_status.has_value() || rd_status.value() < size) {
-    return false;
+  {
+    auto& file{std::move(*expected_file)};
+    if (auto expected_read_result{file.read(file_content)}; !expected_read_result.has_value() || *expected_read_result < size) {
+      return false;
+    }
   }
 
-  file.close();
-
   array<string> result;
   int32_t prev{-1};
   for (size_t i{0}; i < size; i++) {
diff --git a/runtime-light/stdlib/kml/kml-file-api.h b/runtime-light/stdlib/kml/kml-file-api.h
index 3d6f78ccf8..99d79ed6b7 100644
--- a/runtime-light/stdlib/kml/kml-file-api.h
+++ b/runtime-light/stdlib/kml/kml-file-api.h
@@ -120,8 +120,8 @@ class dir_traverser final : public kphp::kml::dir_traverser_interface<dir_traver
     }
 
     struct stat stat {};
-    if (auto stat_result{k2::stat(direntry_path, std::addressof(stat))}; !stat_result.has_value()) [[unlikely]] {
-      kphp::log::warning("[kml] failed to get stat: error code -> {}, path -> {}", stat_result.error(), direntry_path);
+    if (auto expected_stat_result{k2::stat(direntry_path, std::addressof(stat))}; !expected_stat_result.has_value()) [[unlikely]] {
+      kphp::log::warning("[kml] failed to get stat: error code -> {}, path -> {}", expected_stat_result.error(), direntry_path);
       return std::nullopt;
     }
 

From 9d0605cd7400063e91149bdd3c6bf090b6fde33f Mon Sep 17 00:00:00 2001
From: Denis Zubarev <denis.zubarev@vkteam.ru>
Date: Tue, 16 Dec 2025 16:47:40 +0300
Subject: [PATCH 17/17] minor fix

---
 runtime-light/stdlib/file/file-system-functions.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/runtime-light/stdlib/file/file-system-functions.h b/runtime-light/stdlib/file/file-system-functions.h
index ff7835491c..67829322d6 100644
--- a/runtime-light/stdlib/file/file-system-functions.h
+++ b/runtime-light/stdlib/file/file-system-functions.h
@@ -221,9 +221,10 @@ inline Optional<array<string>> f$file(const string& name) noexcept {
     return false;
   }
 
-  kphp::stl::vector<std::byte, kphp::memory::script_allocator> file_content{size};
+  kphp::stl::vector<std::byte, kphp::memory::script_allocator> file_content;
+  file_content.resize(size);
   {
-    auto& file{std::move(*expected_file)};
+    auto file{std::move(*expected_file)};
     if (auto expected_read_result{file.read(file_content)}; !expected_read_result.has_value() || *expected_read_result < size) {
       return false;
     }