test: add fuzz test for private broadcast #35129

pull vasild wants to merge 1 commits into bitcoin:master from vasild:private_broadcast_fuzz changing 3 files +178 −5

vasild commented at 12:57 PM on April 21, 2026: contributor

Add a fuzz test that exercises the public methods of the PrivateBroadcast class from src/private_broadcast.h and checks for correctness.
test: add fuzz test for private broadcast
Co-authored-by: Vasil Dimov <vd@FreeBSD.org>
d31c86f255
DrahtBot added the label Tests on Apr 21, 2026
DrahtBot commented at 12:57 PM on April 21, 2026: contributor



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vasild commented at 1:02 PM on April 21, 2026: contributor

The test was originally provided by @kevkevinpal in #29415 (comment)

There is a complementary fuzz test in #35090 which exercises the peerman / connman call paths while this one here calls directly the PrivateBroadcast methods.
in src/test/fuzz/private_broadcast.cpp:24 in d31c86f255
```
  19 | +
  20 | +FUZZ_TARGET(private_broadcast)
  21 | +{
  22 | +    SeedRandomStateForTest(SeedRand::ZEROS);
  23 | +    FuzzedDataProvider fdp(buffer.data(), buffer.size());
  24 | +    SetMockTime(ConsumeTime(fdp));
```
maflcko commented at 1:17 PM on April 21, 2026:

Please don't use the legacy SetMockTime, which modifies the global and leaks the value between test cases. Probably fine here, but for consistency, I'd avoid it and use NodeClockContext.

Also, it seems odd to hold the value constant, this will limit the possible coverage?
in src/test/fuzz/private_broadcast.cpp:46 in d31c86f255
```
  41 | +            return next_nodeid++;
  42 | +        }
  43 | +        return fdp.ConsumeIntegralInRange<NodeId>(0, next_nodeid - 1);
  44 | +    };
  45 | +
  46 | +    while (fdp.remaining_bytes() > 0) {
```
maflcko commented at 1:19 PM on April 21, 2026:

Please use the LIMITED_WHILE pattern with ConsumeBool(). Otherwise, if something is added later, it will be silently dead code. Of course, it is fine right now, but just taking the risk in the future seems not worth it.
DrahtBot added the label CI failed on Apr 21, 2026
DrahtBot commented at 1:45 PM on April 21, 2026: contributor


🚧 At least one of the CI tasks failed. <sub>Task tidy: https://github.com/bitcoin/bitcoin/actions/runs/24723618894/job/72318638206</sub> <sub>LLM reason (✨ experimental): CI failed because clang-tidy reported a warnings-as-errors performance-unnecessary-copy-initialization in test/fuzz/private_broadcast.cpp (copy-constructing tx from a const reference).</sub>

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fanquake added the label Private Broadcast on Apr 21, 2026

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#34476 Private broadcast tracking

test: add fuzz test for private broadcast #35129

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