RFR: 8372731: Detailed authentication failure messages

[Daniel Fuchs]

On Tue, 2 Dec 2025 11:39:23 GMT, Daniel Jeliński <djelinski at openjdk.org> wrote:

> Currently the HttpUrlConnection throws a generic "Authentication failure" exception when authentication fails locally.
> 
> The authentication may fail for various reasons like: incorrect server challenge message, unavailable encryption/digest algorithms, encoding errors etc. The detailed failure information should be available to the user. Without it, the exception is next to impossible to diagnose, see [JDK-8347778](https://bugs.openjdk.org/browse/JDK-8347778) for example.
> 
> This PR adds the original exception as the cause of the "Authentication failure" exception.
> 
> The detailed exception messages are enabled by the "hostInfo" and "hostInfoExclSocket" categories of "jdk.includeInExceptions". Note that "hostInfoExclSocket" is enabled by default.
> 
> Added a new test to verify that the exception details are present when jdk.includeInExceptions includes hostInfoExclSocket (default), and absent otherwise. Existing tier1-3 tests continue to pass.

Since more than NTLM authentication has been improved, should we test the other authentications too?

test/jdk/sun/net/www/protocol/http/NTLMFailTest.java line 77:

> 75:             HttpURLConnection uc = (HttpURLConnection) url.openConnection();
> 76:             uc.setRequestMethod("HEAD");
> 77:             uc.getInputStream().readAllBytes();

IIUC we're expecting this line to always throw IOException.
Should we throw an assertion error just after line 77 in case the expected IO is not thrown?

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PR Review: https://git.openjdk.org/jdk/pull/28601#pullrequestreview-3552908556
PR Review Comment: https://git.openjdk.org/jdk/pull/28601#discussion_r2599262750