[basvandijk]

Problem

In Rosetta blocks mode, ICP Rosetta's /block serves ledger blocks below the first Rosetta block index F, and Rosetta blocks from F on. A Rosetta block holds one or more ledger blocks, so from F on, Rosetta block indices fall behind ledger block indices. create_parent_block_id resolves a parent at index F or above as a Rosetta block. That is right for Rosetta blocks, but the request handler also used it for ledger blocks:

• /call query_block_range gave ledger blocks Rosetta blocks as parents. When no Rosetta block had the parent's index, as for the newest ledger blocks, it failed with Block not found.
• /search/transactions failed the same way. It computed each block's parent only to discard it.
• /block and /account/balance with only the hash of a ledger block returned a Rosetta parent, or panicked: get_block treats an InvalidBlockId error from the ledger lookup as a Rosetta block hash, and calls todo!("Fetching Rosetta Blocks by hash is not supported yet").

The first two were reported in #11962. This PR builds on its create_parent_block_id over &Blocks.

Fix

• New ledger_block_parent_id: the parent of a ledger block is the previous ledger block, looked up as with Rosetta blocks disabled. It must be verified, and the genesis block is its own parent.
• query_block_range, and hashed_block_to_rosetta_core_block, which converts the ledger blocks of /block, /block/transaction, /account/balance and /network/status, use it.
• /search/transactions builds each block identifier and transaction directly from the ledger block, without a parent.
• create_parent_block_id is renamed rosetta_block_parent_id and is now only used for Rosetta blocks. Below F it uses ledger_block_parent_id.

With Rosetta blocks disabled, responses don't change, with one exception: /search/transactions no longer fails with Block not found when its result includes the oldest block of a pruned store. That block is the first one after the pruned blocks, which /network/status reports as oldest_block_identifier, and its parent is gone. That is the only change in the released image, which is built without the rosetta-blocks feature.

In Rosetta blocks mode, query_block_range ranges that reach unverified ledger blocks now fail with the same retriable InvalidBlockId error as with Rosetta blocks disabled, instead of Block not found.

Testing

New tests in request_handler/tests.rs build their stores the way a sync does:

• test_ledger_blocks_have_ledger_parents_in_rosetta_blocks_mode uses F = 0, with three ledger blocks per Rosetta block.
• test_ledger_blocks_have_ledger_parents_after_the_first_rosetta_block uses F = 2, from a store reopened with Rosetta blocks enabled.

Both check that query_block_range (every range from the genesis block), /search/transactions and /block by the hash of every ledger block return the same as with Rosetta blocks disabled. They also check that Rosetta blocks keep their Rosetta parents.

test_search_transactions_in_pruned_store searches a pruned store with Rosetta blocks disabled.

request_handler.rs	F = 0	F = 2	pruned store
#11962	fails	fails	fails
only query_block_range fixed	fails	fails	fails
everything fixed except /block by hash	fails	fails	passes
below F, the ledger parent of the parent index (off by one)	passes	fails	passes
/search/transactions resolves ledger parents	passes	passes	fails
this PR	passes	passes	passes

With this PR, only Rosetta blocks reach rosetta_block_parent_id, the method that deadlocked in #11962. So #11962's test_requests_do_not_deadlock_with_concurrent_writer now also runs with Rosetta blocks enabled. A variant of this PR that takes the read lock again in that method fails only the new Rosetta blocks run.

All 11 non-system test targets that depend on the changed files pass locally, including rosetta-integration_tests and the ICRC Rosetta suites. So do the four _local variants of the rs/tests/financial_integrations/rosetta system tests, which PR CI doesn't run because they're tagged long_test. Their Farm variants weren't run.

Not changed here

• In Rosetta blocks mode, query_block_range and /search/transactions still return ledger block identifiers (the TODO in query_block_range), while from F on /block serves Rosetta blocks at those indices. This PR makes the ledger blocks they return consistent with each other, not with the Rosetta blocks.
• In Rosetta blocks mode, /block by the hash of a stored but unverified ledger block still panics in the todo!().
• In Rosetta blocks mode, /account/balance at Rosetta block r returns the balance at ledger block r, not at the last ledger block in Rosetta block r.
• With Rosetta blocks disabled, /block and query_block_range still fail for the oldest block of a pruned store, whose parent is gone, although /network/status reports it as the oldest block.

This PR fixes an issue reported in #11962, which was created following the steps in .claude/skills/fix-flaky-tests/SKILL.md.

🤖 Generated with Claude Code

[Copilot]

🟢 Approval recommended

The focused changes preserve Rosetta parent behavior, cover the affected boundaries with regression tests, and have no identified blocking issues.

No open issues 🎉

What changed in this PR

This PR fixes ledger-block parent identifiers in ICP Rosetta’s Rosetta blocks mode, building on the earlier read-lock deadlock fix.

Changes:

• Separates ledger and Rosetta parent lookups while preserving the boundary between their chains.
• Removes unnecessary parent lookups from transaction searches, allowing searches to include the oldest retained block after pruning.
• Adds regression coverage for both Rosetta-mode boundaries, pruned stores, and concurrent writer access.

File	Description
rs/​rosetta-api/​icp/​src/​request_handler/​tests.rs	Adds parent-chain and pruning tests; extends concurrent-access coverage to Rosetta blocks mode.
rs/​rosetta-api/​icp/​src/​request_handler.rs	Uses ledger-specific parent lookup and converts search results without resolving parents.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues remain for the ledger/Rosetta parent-resolution and transaction-search changes.

No open issues 🎉

_{Review effort: Balanced}

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to ab080c8.

Security Overview

• 🔎 Scanned files: 2 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/bd30fac0-c6f5-4bec-83e2-480d2b345946?scanId=fd4af6a0-7d30-4f27-ae3a-da0a2db0e4da&codeScanTypes=PrScan&tab=issues&detectionTypes=traditional,businessLogic,customRule,IAC,SECRETS,CICD,EOL,uncategorized

Detected Code Changes

Change Type

Relevant files

Enhancement

► rs/rosetta-api/icp/src/request_handler.rs       Replace create_parent_block_id with ledger_block_parent_id in several call paths ► rs/rosetta-api/icp/src/request_handler.rs       Rename create_parent_block_id to rosetta_block_parent_id and adjust usages ► rs/rosetta-api/icp/src/request_handler.rs       Introduce ledger_block_parent_id helper and related logic ► rs/rosetta-api/icp/src/request_handler/tests.rs       Update tests to accommodate new parent id logic and Rosetta blocks mode ► rs/rosetta-api/icp/src/request_handler/tests.rs       Add tests for ledger block parent handling in Rosetta blocks mode ► rs/rosetta-api/icp/src/request_handler/tests.rs       Add utility functions for ledger blocks creation and synchronization ► rs/rosetta-api/icp/src/request_handler/tests.rs       Add tests for pruned store transaction search and Rosetta blocks interactions

[Copilot]

🟢 Approval recommended

No active review issues were identified for the ledger-parent and transaction-search changes.

No open issues 🎉

_{Review effort: Balanced}