RFR(XS): 8231885: Fix/remove malformed assert in os_windows.cpp

[Schmelter, Ralf]

Hi,

the assertion should be OK in principle, since the path was already modified by os::native_path(), which (correctly) claims to convert all slashes to backslashes and consolidate a sequence of backslashes to one backslash (or 2 for the starting backslash). So if the user supplied path is '\\\test\\a', os::native:path() will convert it to '\\test\a'. But I'm OK with it being removed too.

Best regards,
Ralf

From: Langer, Christoph <christoph.langer at sap.com>
Sent: Freitag, 4. Oktober 2019 15:27
To: hotspot-runtime-dev at openjdk.java.net
Cc: Schmelter, Ralf <ralf.schmelter at sap.com>
Subject: RFR(XS): 8231885: Fix/remove malformed assert in os_windows.cpp

Hi,

please review a one(two)-line fix for a recent change in os_windows.cpp.

The fix introduced a malformed assertion which doesn't provide an assertion message. Testing in jdk/jdk wouldn't bring up the issue but I just discovered it when attempting to backport it to jdk11. Probably due to the older compiler or some other thing that is different there the fastdebug build failed.

One could add a message to the assertion. But I think handing a malformed path that starts with 3 or more '\' to wide_abs_unc_path will either cause an error code and the caller should be able to cope with that or windows is tolerant enough to accept it as a UNC path still. We can leave that to the operating system. So I decided to simply remove the assertion.

Bug: https://bugs.openjdk.java.net/browse/JDK-8231885
Problematic statement: http://hg.openjdk.java.net/jdk/jdk/file/13f29c43b6c7/src/hotspot/os/windows/os_windows.cpp#l4192

Fix:

diff -r e25b317d0350 -r 3f89a4aa0c2d src/hotspot/os/windows/os_windows.cpp
--- a/src/hotspot/os/windows/os_windows.cpp     Thu Oct 03 18:59:56 2019 +0100
+++ b/src/hotspot/os/windows/os_windows.cpp     Fri Oct 04 14:11:47 2019 +0100
@@ -4189,8 +4189,6 @@
     if (::isalpha(buf[0]) && !::IsDBCSLeadByte(buf[0]) && buf[1] == ':' && buf[2] == '\\') {
       prefix = L"\\\\?\\";
     } else if (buf[0] == '\\' && buf[1] == '\\') {
-      assert(buf[2] != '\\');
-
       if (buf[2] == '?' && buf[3] == '\\') {
         prefix = L"";
         needs_fullpath = false;


Thanks
Christoph