ICU-22541 Fix MacOS 14 default timezone issue

See unicode-org#2669
MrJithil · Oct 25, 2023 · 81e26e0 · 81e26e0
1 parent 680f521
commit 81e26e0
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Showing 2 changed files with 18 additions and 6 deletions.
diff --git a/icu4c/source/common/putil.cpp b/icu4c/source/common/putil.cpp
@@ -1175,6 +1175,21 @@ uprv_tzname(int n)
         if (ret != nullptr && uprv_strcmp(TZDEFAULT, gTimeZoneBuffer) != 0) {
             int32_t tzZoneInfoTailLen = uprv_strlen(TZZONEINFOTAIL);
             const char *tzZoneInfoTailPtr = uprv_strstr(gTimeZoneBuffer, TZZONEINFOTAIL);
+            // MacOS14 has the realpath as something like
+            // /usr/share/zoneinfo.default/Australia/Melbourne
+            // which will not have "/zoneinfo/" in the path.
+            // Therefore if we fail, we fall back to read the link which is
+            // /var/db/timezone/zoneinfo/Australia/Melbourne
+            // We also fall back to reading the link if the realpath leads to something like
+            // /usr/share/zoneinfo/posixrules
+            if (tzZoneInfoTailPtr == nullptr ||
+                    uprv_strcmp(tzZoneInfoTailPtr + tzZoneInfoTailLen, "posixrules") == 0) {
+                ssize_t size = readlink(TZDEFAULT, gTimeZoneBuffer, sizeof(gTimeZoneBuffer)-1);
+                if (size > 0) {
+                    gTimeZoneBuffer[size] = 0;
+                    tzZoneInfoTailPtr = uprv_strstr(gTimeZoneBuffer, TZZONEINFOTAIL);
+                }
+            }
             if (tzZoneInfoTailPtr != nullptr) {
                 tzZoneInfoTailPtr += tzZoneInfoTailLen;
                 skipZoneIDPrefix(&tzZoneInfoTailPtr);

diff --git a/icu4c/source/test/depstest/dependencies.txt b/icu4c/source/test/depstest/dependencies.txt
@@ -22,7 +22,7 @@ system_symbols:
     exp_and_tanhf
     stdlib_qsort
     system_locale
-    stdio_input stdio_output file_io realpath_function dir_io mmap_functions dlfcn
+    stdio_input stdio_output file_io dir_io mmap_functions dlfcn
     # C++
     cplusplus iostream
     std_mutex
@@ -110,11 +110,8 @@ group: file_io
     # Additional symbols in an optimized build.
     __xstat
 
-group: realpath_function
-    realpath  # putil.cpp uprv_tzname() calls this in a hack to get the time zone name
-
 group: dir_io
-    opendir closedir readdir  # for a hack to get the time zone name
+    opendir closedir readdir readlink realpath # for a hack to get the time zone name
 
 group: mmap_functions  # for memory-mapped data loading
     mmap munmap
@@ -869,7 +866,7 @@ group: platform
     PIC system_misc system_debug malloc_functions ubsan
     c_strings c_string_formatting
     floating_point system_locale
-    stdio_input realpath_function dir_io
+    stdio_input dir_io
     dlfcn  # Move related code into icuplug.c?
     cplusplus
     std_mutex