Fix ValueError in TraceParser when parameter value contains ' = '

[fdcastel]

Summary

TraceParser._parse_parameters_block (in src/firebird/lib/trace.py) calls line.split(' = ') without a maxsplit argument. When a parameter line's value itself contains the substring = — entirely legal, since a varchar column can carry arbitrary text, including key=value-shaped strings — the split yields 3+ parts and the unpacking on the same line raises:

ValueError: too many values to unpack (expected 2, got N)

Because _parse_parameters_block is called from _parse_parameters and from __parser_func_finish (the returns: block of function-finish events), the failure silently drops the enclosing trace block on every event that carries parameters or function-return values. The error propagates out of parse_event, but typical streaming consumers swallow it per-block, and one bad row eats real telemetry.

Repro

A trace block with a parameter whose value contains =, e.g. param0 = varchar(80), \"alpha = 1; beta = 2\", triggers the ValueError before the fix. Added as test_68_param_value_containing_equals in tests/test_trace.py; without the patch, the new test fails at line 1386 with ValueError: too many values to unpack (expected 2, got 4). With the patch, all 21 tests in test_trace.py pass.

Fix

One-character change: line.split(' = ', maxsplit=1). The second = (and any after) stays inside the value, where it belongs. The expected (name, value) shape of the unpacking is preserved.

-            _, param_def = line.split(' = ')
+            _, param_def = line.split(' = ', maxsplit=1)

Both call sites of _parse_parameters_block (in _parse_parameters at line ~1390 and in __parser_func_finish at line ~1755) inherit the fix.

Out of scope

Multi-line parameter values that span multiple __current_block entries (line continuation) are a separate parsing concern and are not addressed here.

Test plan

• pytest tests/test_trace.py passes (21/21) with the fix applied.
• Reverting the fix while keeping the new test causes test_68_param_value_containing_equals to fail with the expected ValueError at the patched line.
• CI green on this PR.