Fix error callback cookie usage

[rgerhards]

Summary

• ensure ln_errprintf forwards the configured error callback cookie
• add a unit test that confirms the error callback receives the registered cookie and hook it into the test suite

Testing

• autoreconf -fi (fails: aclocal is not available in the container)

---

https://chatgpt.com/codex/tasks/task_e_68cbac0f01488332a647a95b40c38351

[gemini-code-assist]

Summary of Changes

Hello @rgerhards, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a subtle but important bug in the error handling mechanism where the incorrect cookie was being passed to the error callback function. The primary change ensures that the ln_errprintf function uses the errmsgCookie instead of dbgCookie. To prevent future regressions and validate the fix, a dedicated unit test has been introduced, which verifies the proper forwarding of the error callback cookie.

Highlights

• Error Callback Cookie Fix: The ln_errprintf function now correctly forwards the configured error callback cookie to the error message callback function, resolving an issue where the wrong cookie was being passed.
• New Unit Test: A new unit test, err_callback_cookie, has been added to confirm that the error callback receives the registered cookie as expected. This test is integrated into the existing test suite.

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[gemini-code-assist]

Code Review

This pull request correctly fixes a bug where the error callback was being passed the debug cookie instead of the error cookie. The addition of a unit test to verify this fix is also a great inclusion. I've provided a few suggestions to improve code style and enhance the new test's clarity and robustness, mainly by fixing an indentation issue and adding better error reporting to the test case for easier debugging.

[gemini-code-assist]

This line has inconsistent indentation (7 spaces). It should be aligned with the following line. Using a tab would be consistent with the project's style, but aligning it with 8 spaces would also improve readability.

        ctx->errmsgCB(ctx->errmsgCookie, msg, lenBuf);

[gemini-code-assist]

It's good practice for tests to report why they failed. To add error logging using fprintf for better diagnostics (as suggested in other comments), please include the <stdio.h> header here.

#include <stdio.h>

[gemini-code-assist]

The check if(cookie == state) is redundant because state is assigned the value of cookie on line 13. This condition will always be true if state is not NULL. You can simplify the code by removing this if statement.

                state->cookie_match = 1;

[gemini-code-assist]

If ln_initCtx() fails, the test exits with a failure code but provides no information about what went wrong. Adding an error message to stderr would make it easier to debug test failures.

        if(ctx == NULL) {
                fprintf(stderr, "ln_initCtx() failed\n");
                return ret;
        }

[gemini-code-assist]

Similar to the context initialization, if ln_setErrMsgCB() fails, the test will fail without indicating the cause. Adding an error message here would improve debuggability.

        if(ln_setErrMsgCB(ctx, error_callback, &state) != 0) {
                fprintf(stderr, "ln_setErrMsgCB() failed\n");
                goto done;
        }