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Summary

Evict completed DHT block statistics from active_blocks in both the light client and fat client.

Problem

Each DHT PUT task creates or updates a BlockStat entry keyed by block height. When all PUT operations for a block complete, the clients record the success rate and duration but never remove the completed block from active_blocks.

For long-running clients, this causes the map to retain statistics for every block that has performed a DHT PUT operation.

Additionally, remaining_counter -= 1 can underflow if libp2p emits a duplicate or late completion event. This can panic in debug builds and wrap to a large value in release builds.

Fix

• Calculate completion metrics while holding the mutable block borrow.
• End the borrow before removing the completed block from active_blocks.
• Remove completed block statistics from both success and failure paths.
• Replace unchecked counter decrement with checked_sub.
• Return an explicit error for unknown, duplicate, or late completion events.
• Add regression tests for successful, mixed, parallel, duplicate, and reused block-statistics cycles.

Tests

cargo test -p avail-light-client --bin avail-light-client
cargo test -p avail-light-client --no-default-features --bin avail-light-client
cargo test -p avail-light-fat --bin avail-light-fat
cargo test -p avail-light-fat --no-default-features --bin avail-light-fat
cargo clippy -p avail-light-client --no-default-features --bin avail-light-client -- -D warnings
cargo clippy -p avail-light-fat --no-default-features --bin avail-light-fat -- -D warnings

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@aterentic-ethernal Hi, Could you please review this PR at your convenience? Thank you very much.

[aterentic-ethernal]

Looks good, thank you for contribution :)

[zloglevel]

Looks good, thank you for contribution :)

I have resolved the clippy warning. Please review it again.

@aterentic-ethernal Thanks.