fuzz: wallet: add target for spkm migration #29694

This PR adds a fuzz target for ScriptPubKeyMan migration. It creates a LegacyDataSPKM which can have some keys/scripts/etc, and then migrate it to descriptor. I tried to keep it as compatible as possible with future legacy wallet removal.

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The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/29694.

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Reviews

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #28710 (Remove the legacy wallet and BDB dependency by achow101)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

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cc: @achow101

Inputs for this are available at: https://github.com/brunoerg/qa-assets/pull/2

Coverage for this target: https://drahtbot.space/host_reports/DrahtBot/reports/coverage_fuzz/monotree/2e7ac47bbc28c2cb/300ddaa72f7e4b9b/fuzz.coverage/index.html

Force-pushed addressing (multisig and hd chain cover):

• #29694 (review)
• #29694 (review)

Would be good to ensure that #31374 can be replicated here.

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🚧 At least one of the CI tasks failed. _{Debug: https://github.com/bitcoin/bitcoin/runs/33561912794}

<details><summary>Hints</summary>

Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

• Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

• A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

• An intermittent issue.

Leave a comment here, if you need help tracking down a confusing failure.

</details>

Force-pushed addressing #29694 (review)

Would be good to ensure that #31374 can be replicated here.

Since this target is only for spkm migration, I don't think it can be replicated here.

Edit: I can add ApplyMigrationData here and reproduce the crash from #31374. I'm going to move this to draft while working on it.

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🚧 At least one of the CI tasks failed. _{Debug: https://github.com/bitcoin/bitcoin/runs/33784139981}

<details><summary>Hints</summary>

Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

• Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

• A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

• An intermittent issue.

Leave a comment here, if you need help tracking down a confusing failure.

</details>

Force-pushed changing the fuzz target to address the ApplyMigrationData function. Now, after migrating the spk to descriptor, it creates some transactions and apply the migrated data.

Note that the CI failure is expected (see #31374):

[09:11:48.112] Run spkm_migration with args ['/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/fuzz', '-max_total_time=60']INFO: Running with entropic power schedule (0xFF, 100).
[09:11:48.112] INFO: Seed: 2346481497
[09:11:48.112] INFO: Loaded 1 modules   (629856 inline 8-bit counters): 629856 [0x55a29859f118, 0x55a298638d78), 
[09:11:48.112] INFO: Loaded 1 PC tables (629856 PCs): 629856 [0x55a298638d78,0x55a298fd5378), 
[09:11:48.112] INFO: -max_len is not provided; libFuzzer will not generate inputs larger than 4096 bytes
[09:11:48.112] wallet/wallet.cpp:4088 ApplyMigrationData: Assertion `!m_cached_spks.empty()' failed.

Force-pushed:

Now the fuzz target runs the entire migration process (MigrateLegacyToDescriptor). Also, I added a new commit that allows to migrate in-memory wallets to speed up the target and avoid timeouts.

Force-pushed adding SeedRandomStateForTest and SetMockTime for better stability.

Rebased

https://cirrus-ci.com/task/5046981191532544?logs=ci#L1799

[22:03:02.859]  test  2025-01-27T22:03:01.984000Z TestFramework (ERROR): Assertion failed 
[22:03:02.859]                                    Traceback (most recent call last):
[22:03:02.859]                                      File "/ci_container_base/test/functional/test_framework/test_framework.py", line 135, in main
[22:03:02.859]                                        self.run_test()
[22:03:02.859]                                      File "/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/test/functional/wallet_migration.py", line 1098, in run_test
[22:03:02.859]                                        self.test_failed_migration_cleanup()
[22:03:02.859]                                      File "/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/test/functional/wallet_migration.py", line 899, in test_failed_migration_cleanup
[22:03:02.859]                                        assert all(wallet not in self.master_node.listwallets() for wallet in ["failed", "failed_watchonly", "failed_solvables"])
[22:03:02.859]                                    AssertionError

Just fixed CI, ready for review!

You are skipping the backup restore in commit: "wallet: skip backup restoration when using in-memory dbs"; shouldn't the backup itself be skipped too when in_memory?

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🐙 This pull request conflicts with the target branch and needs rebase.

I'm reworking this target, will draft it.

Closing in favor of #32624.