feat(php-shim): render human-facing timestamps in the local timezone

Split date() into date_utc() and date_local(), the latter resolving the
system's local timezone through the tzfile crate ($TZ, then
/etc/localtime, falling back to UTC when neither is readable). The
timestamps Composer renders for humans -- the GitHub OAuth token note,
the GitHub API rate limit reset time, the Perforce client spec fields and
the "today" check of the show command -- now go through date_local().

PHP resolves its default timezone from the date.timezone ini setting,
which Shirabe does not read, so date_default_timezone_get/set have no
input left to model and are dropped from the shim and its callers. The
resulting difference is recorded in docs/known-incompatibilities.md.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

6 files changed, 17 insertions, 28 deletions

diff --git a/crates/shirabe/src/command/show_command.rs b/crates/shirabe/src/command/show_command.rs
index e5d5a1f2..f2246cbe 100644
--- a/crates/shirabe/src/command/show_command.rs
+++ b/crates/shirabe/src/command/show_command.rs
@@ -39,8 +39,8 @@ use indexmap::IndexMap;
 use shirabe_pcre::{CaptureKey, Preg};
 use shirabe_php_shim::{
     CmpOp, DATE_ATOM, InvalidArgumentException, LogicException, PhpMixed, UnexpectedValueException,
-    array_search, date, date_format_to_strftime, extension_loaded, impl_php_class, in_array_loose,
-    in_array_strict, php_regex, realpath, strtolower, version_compare,
+    array_search, date_format_to_strftime, date_local, extension_loaded, impl_php_class,
+    in_array_loose, in_array_strict, php_regex, realpath, strtolower, version_compare,
 };
 use shirabe_semver::Semver;
 use shirabe_semver::constraint::AnyConstraint;
@@ -1484,7 +1484,7 @@ impl ShowCommand {
         if release_date
             .format(date_format_to_strftime("Ymd"))
             .to_string()
-            == date("Ymd", None)
+            == date_local("Ymd", None)
         {
             return "today".to_string();
         }
diff --git a/crates/shirabe/src/console/application.rs b/crates/shirabe/src/console/application.rs
index 3e4a746b..9a17868c 100644
--- a/crates/shirabe/src/console/application.rs
+++ b/crates/shirabe/src/console/application.rs
@@ -57,13 +57,12 @@ use crate::util::Silencer;
 use indexmap::IndexMap;
 use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{
-    LogicException as ShimLogicException, PhpMixed, RuntimeException, bin2hex, chdir,
-    date_default_timezone_get, date_default_timezone_set, defined, dirname, disk_free_space,
-    extension_loaded, file_exists, file_get_contents, file_put_contents, function_exists, getcwd,
-    getmypid, glob, ini_set, is_array, is_dir, is_file, is_string, json_decode,
-    memory_get_peak_usage, memory_get_usage, microtime, php_regex, php_uname, posix_getuid,
-    random_bytes, realpath, restore_error_handler, round, str_replace, strpos, strtoupper,
-    sys_get_temp_dir, time, unlink,
+    LogicException as ShimLogicException, PhpMixed, RuntimeException, bin2hex, chdir, defined,
+    dirname, disk_free_space, extension_loaded, file_exists, file_get_contents, file_put_contents,
+    function_exists, getcwd, getmypid, glob, ini_set, is_array, is_dir, is_file, is_string,
+    json_decode, memory_get_peak_usage, memory_get_usage, microtime, php_regex, php_uname,
+    posix_getuid, random_bytes, realpath, restore_error_handler, round, str_replace, strpos,
+    strtoupper, sys_get_temp_dir, time, unlink,
 };
 use shirabe_seld_json_lint::ParsingException;
 use shirabe_symfony_console::application::Application as BaseApplication;
@@ -157,13 +156,6 @@ impl Application {
             ini_set("xdebug.scream", "0");
         }
 
-        if function_exists("date_default_timezone_set")
-            && function_exists("date_default_timezone_get")
-        {
-            let tz = Silencer::call(|| Ok(date_default_timezone_get())).unwrap_or_default();
-            date_default_timezone_set(&tz);
-        }
-
         let io: std::rc::Rc<std::cell::RefCell<dyn IOInterface>> =
             std::rc::Rc::new(std::cell::RefCell::new(NullIO::new()));
 
diff --git a/crates/shirabe/src/util/github.rs b/crates/shirabe/src/util/github.rs
index 26756ed0..25a95e57 100644
--- a/crates/shirabe/src/util/github.rs
+++ b/crates/shirabe/src/util/github.rs
@@ -10,7 +10,7 @@ use crate::util::ProcessExecutor;
 use indexmap::IndexMap;
 use shirabe_pcre::{CaptureKey, Preg};
 use shirabe_php_shim::Catch as _;
-use shirabe_php_shim::{PhpMixed, date, in_array_loose, php_regex, stripos, strtolower};
+use shirabe_php_shim::{PhpMixed, date_local, in_array_loose, php_regex, stripos, strtolower};
 
 #[derive(Debug)]
 pub struct GitHub {
@@ -106,7 +106,7 @@ impl GitHub {
                 note += &format!(" on {}", output.trim());
             }
         }
-        note += &format!(" {}", date("Y-m-d Hi", None));
+        note += &format!(" {}", date_local("Y-m-d Hi", None));
 
         let (local_name, auth_name): (Option<String>, String) = {
             let cfg = self.config.borrow();
@@ -309,7 +309,7 @@ impl GitHub {
                     let ts: i64 = value.trim().parse().unwrap_or(0);
                     rate_limit.insert(
                         "reset".to_string(),
-                        PhpMixed::String(date("Y-m-d H:i:s", Some(ts))),
+                        PhpMixed::String(date_local("Y-m-d H:i:s", Some(ts))),
                     );
                 }
                 _ => {}
diff --git a/crates/shirabe/src/util/perforce.rs b/crates/shirabe/src/util/perforce.rs
index 1820936c..246e37f5 100644
--- a/crates/shirabe/src/util/perforce.rs
+++ b/crates/shirabe/src/util/perforce.rs
@@ -8,7 +8,7 @@ use crate::util::ProcessExecutor;
 use indexmap::IndexMap;
 use shirabe_pcre::Preg;
 use shirabe_php_shim::{
-    Exception, PHP_EOL, PhpMixed, PhpResource, chdir, date, explode, fclose, feof, fgets,
+    Exception, PHP_EOL, PhpMixed, PhpResource, chdir, date_local, explode, fclose, feof, fgets,
     file_get_contents, fopen, fwrite, gethostname, json_decode, php_regex, str_replace_array,
     strcmp, strlen, strpos, strrpos, substr, time, trim,
 };
@@ -414,7 +414,7 @@ impl Perforce {
             spec,
             format!(
                 "Update: {}{}{}",
-                date("Y/m/d H:i:s", None),
+                date_local("Y/m/d H:i:s", None),
                 PHP_EOL,
                 PHP_EOL
             ),
@@ -422,7 +422,7 @@ impl Perforce {
         );
         fwrite(
             spec,
-            format!("Access: {}{}", date("Y/m/d H:i:s", None), PHP_EOL),
+            format!("Access: {}{}", date_local("Y/m/d H:i:s", None), PHP_EOL),
             None,
         );
         fwrite(
diff --git a/crates/shirabe/tests/command/show_command_test.rs b/crates/shirabe/tests/command/show_command_test.rs
index 47eae462..20dbf848 100644
--- a/crates/shirabe/tests/command/show_command_test.rs
+++ b/crates/shirabe/tests/command/show_command_test.rs
@@ -8,7 +8,7 @@ use serial_test::serial;
 use shirabe::package::Link;
 use shirabe::package::handle::PackageInterfaceHandle;
 use shirabe::repository::PlatformRepository;
-use shirabe_php_shim::PhpMixed;
+use shirabe_php_shim::{PhpMixed, date_local};
 
 /// Build a `Vec<(PhpMixed, PhpMixed)>` command input from `(key, value)` pairs.
 fn input(pairs: Vec<(&str, PhpMixed)>) -> Vec<(PhpMixed, PhpMixed)> {
@@ -1028,7 +1028,7 @@ fn test_self_and_package_combination() {
             match and prints \"this week\" whenever the local date differs from the UTC date \
             (e.g. daily 00:00-09:00 JST); see TODO(php-semantics) in shirabe-php-shim datetime.rs"]
 fn test_self() {
-    let today = chrono::Local::now().format("%Y-%m-%d").to_string();
+    let today = date_local("Y-m-d", None);
     let _tear_down = init_temp_composer(
         Some(&serde_json::json!({
             "name": "vendor/package",
diff --git a/crates/shirabe/tests/common/bootstrap.rs b/crates/shirabe/tests/common/bootstrap.rs
index a908bff2..9f667597 100644
--- a/crates/shirabe/tests/common/bootstrap.rs
+++ b/crates/shirabe/tests/common/bootstrap.rs
@@ -18,9 +18,6 @@ pub fn bootstrap() {
     ONCE.call_once(|| {
         // PHP: error_reporting(E_ALL) has no counterpart here.
 
-        // PHP: date_default_timezone_set(@date_default_timezone_get());
-        shirabe_php_shim::date_default_timezone_set(&shirabe_php_shim::date_default_timezone_get());
-
         // PHP: require src/bootstrap.php and refresh vendor/composer/InstalledVersions.php.
         // TODO(php-runtime): port remaining bootstrap processes (the src/bootstrap.php include and
         // the InstalledVersions refresh are PHP autoload mechanics with no Rust counterpart yet).