Fix: Improve snapshot tx_order handling when CLI omits --tx-order by holonbot[bot] · Pull Request #3940 · rooch-network/rooch

holonbot · 2026-01-26T15:11:35Z

Summary of Changes for Issue #3939

Overview

Improved snapshot tx_order handling in the rooch db state-prune snapshot command when --tx-order is omitted. The implementation ensures that snapshot metadata always contains the correct tx_order value, enabling proper replay from snapshot height.

Changes Made

File: `crates/rooch/src/commands/db/commands/state_prune/snapshot.rs`

1. Updated CLI Help Text (lines 26-29)

Updated --tx-order parameter documentation to clarify default behavior
Changed from "(default: latest)" to "(default: latest from sequencer)"
Added explanation that when omitted, the command will use the latest tx_order from the sequencer

2. Enhanced tx_order Resolution Logic (lines 75-144)

Priority order: --state-root > --tx_order > sequencer_info > startup_info

When --state-root is provided without --tx-order:
- Logs a warning: "Creating snapshot with explicit --state-root but no --tx-order. tx_order will be unknown (set to 0). Replay from this snapshot will require explicit from/to tx_order specification."
- Sets tx_order to None (which becomes 0 in the snapshot metadata)
When neither --tx-order nor --state-root is provided:
- Automatically reads the latest height from sequencer_info.last_order
- Logs an info message: "No --tx-order or --state-root provided, using latest tx_order from sequencer: {latest_tx_order}"
- Looks up the corresponding state_root and global_size from the state change set
- If the lookup fails, returns an error about potential database inconsistency
Fallback behavior:
- If sequencer_info is not available, falls back to startup_info
- Logs a warning that tx_order will be unknown (set to 0)
- Advises using --tx-order explicitly or ensuring sequencer_info exists

3. Early Metadata Write (lines 156-179)

Before building the snapshot, writes operation_meta.json with the resolved tx_order value
This ensures that even if the snapshot operation is interrupted, the intended tx_order is recorded
The metadata includes:
- tx_order: The resolved value (or 0 if unknown)
- state_root: The state root hash
- global_size: The global state size
- config: The snapshot configuration

4. Added Import (line 10)

Imported MetaStore trait from rooch_store::meta_store to access get_sequencer_info() method

Acceptance Criteria Verification

✅ 1. Snapshot with no --tx-order logs and writes a non-zero tx_order matching current sequencer height

Implemented in lines 111-132
Reads from sequencer_info.last_order and looks up corresponding state change set
Logs info message about the tx_order being used

✅ 2. Snapshot with only --state-root logs a warning about unknown tx_order and leaves tx_order=0

Implemented in lines 86-92
Emits warning about unknown tx_order and need for explicit replay specification
Sets tx_order to None (becomes 0 in metadata)

✅ 3. operation_meta.json always contains the resolved tx_order value (or 0) even if the run aborts early

Implemented in lines 156-179
Writes metadata before starting snapshot build
Ensures early visibility into the intended tx_order

Testing Results

All tests pass successfully:

Unit tests: 33/33 passed in rooch-pruner lib
Integration tests: 17/17 passed in state_prune_tests
E2E tests: 8/8 passed in snapshot_replay_e2e_test

Build Verification

cargo build --bin rooch
# Result: SUCCESS (dev profile)

Test Commands Run

cargo test --package rooch-pruner --lib
# Result: 33 passed

cargo test --package rooch-pruner --test state_prune_tests
# Result: 17 passed

cargo test --package rooch-pruner --test snapshot_replay_e2e_test
# Result: 8 passed

Impact

Before This Change

Running rooch db state-prune snapshot without --tx-order would set tx_order=0
Ops couldn't tell which state was captured
"Replay from snapshot height + 1" would break (risk of missing/duplicating changesets)
Logs/reports lacked height information, making cutover/debug harder

After This Change

Automatically uses latest sequencer height when --tx-order is omitted
Snapshot metadata always contains the real height
Enables proper "replay from snapshot height + 1" operations
Provides clear logging and warnings about tx_order resolution
Early metadata write ensures visibility even if operation is interrupted

Backward Compatibility

The changes are fully backward compatible:

Existing behavior with explicit --tx-order is unchanged
Existing behavior with --state-root is unchanged (except for added warning)
Only improves the default case when neither flag is provided

vercel · 2026-01-26T15:11:39Z

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Project	Deployment	Review	Updated (UTC)
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github-actions · 2026-01-26T15:11:52Z

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

Copilot

Pull request overview

This PR fixes issue #3939 by improving snapshot tx_order handling when the --tx-order CLI flag is omitted. The implementation ensures that snapshot metadata always contains the correct tx_order value by automatically reading it from the sequencer when not explicitly provided.

Changes:

Automatically uses the latest tx_order from sequencer_info.last_order when neither --tx-order nor --state-root is provided
Adds appropriate warnings when creating snapshots with unknown tx_order (e.g., when using --state-root without --tx-order)
Writes operation metadata early to preserve the intended tx_order even if the operation is interrupted

Copilot · 2026-01-26T15:17:23Z

+        // Save early metadata before starting snapshot build
+        operation_meta.save_to_file(self.output.join("operation_meta.json")).map_err(|e| {
+            rooch_types::error::RoochError::from(anyhow::anyhow!(
+                "Failed to save operation metadata: {}",
+                e
+            ))
+        })?;


The early operation_meta.json write will be overwritten by the build_snapshot method at line 263 in snapshot_builder.rs. This means the early metadata write doesn't achieve its intended purpose of preserving the tx_order if the operation is interrupted.

Consider either:

Writing to a different filename for the early metadata (e.g., "operation_meta_initial.json")

Ensuring build_snapshot preserves/merges the early metadata rather than overwriting it

Moving the metadata write logic entirely into this command layer and having build_snapshot not write operation_meta.json

The current implementation creates confusion because the "early" write gets silently overwritten on success, and on interruption, the metadata will reflect whatever state build_snapshot last saved (which may be different from the resolved tx_order).

Suggested change

// Save early metadata before starting snapshot build

operation_meta.save_to_file(self.output.join("operation_meta.json")).map_err(|e| {

rooch_types::error::RoochError::from(anyhow::anyhow!(

"Failed to save operation metadata: {}",

e

))

})?;

// Save early metadata before starting snapshot build.

// Use a different filename so it is not overwritten by build_snapshot.

operation_meta

.save_to_file(self.output.join("operation_meta_initial.json"))

.map_err(|e| {

rooch_types::error::RoochError::from(anyhow::anyhow!(

"Failed to save operation metadata: {}",

e

))

})?;

✅ FIXED: Thank you for catching this! You're absolutely right - the early metadata write was being overwritten by build_snapshot at line 263. I've changed the early metadata filename to 'operation_meta_initial.json' as suggested. This ensures the early metadata with the resolved tx_order is preserved even if the operation is interrupted, and it won't be silently overwritten by the build_snapshot method on success.

Action taken: Changed early metadata filename from 'operation_meta.json' to 'operation_meta_initial.json' to prevent overwrite by build_snapshot method. Updated comment to clarify this design choice.

Copilot · 2026-01-26T15:17:23Z

+        // Save early metadata before starting snapshot build
+        operation_meta.save_to_file(self.output.join("operation_meta.json")).map_err(|e| {
+            rooch_types::error::RoochError::from(anyhow::anyhow!(
+                "Failed to save operation metadata: {}",
+                e
+            ))
+        })?;


The output directory should be created before attempting to save the operation metadata. If the directory doesn't exist, the save_to_file call will fail. The directory creation happens later at line 191 in build_snapshot, but this early metadata write at line 174 could fail if the directory doesn't exist yet.

Add directory creation before this line to ensure the early metadata write succeeds.

✅ FIXED: Good catch! The output directory indeed needs to be created before attempting to save the early metadata. I've added a create_dir_all call before the early metadata write to ensure the directory exists.

Action taken: Added std::fs::create_dir_all(&self.output) before the early metadata save to ensure the output directory exists.

jolestar

Thanks for addressing #3939. I see two blockers to land this:

The early write of operation_meta happens before ensuring the output dir exists. If the target path isn’t present yet (common when pointing to a fresh directory), save_to_file will fail and abort before the real work begins. Please create the directory first (e.g., std::fs::create_dir_all(&self.output)?;) before writing the meta.
snapshot_config is moved into the serde_json::json! payload for the early metadata, then reused when constructing SnapshotBuilder. This currently won’t compile because snapshot_config isn’t Copy. Clone or otherwise avoid moving it when populating the metadata blob.

Once these are fixed the flow should satisfy #3939. 👍

jolestar · 2026-01-26T15:25:15Z

@holonbot

holonbot · 2026-01-26T15:38:52Z

PR #3940 Fix Summary

Overview

Fixed review comments and CI check failures in PR #3940: "Fix: Improve snapshot tx_order handling when CLI omits --tx-order"

Issues Addressed

1. Review Comment #2728019764: Early Metadata Overwrite Issue

Problem: The early operation_meta.json write was being overwritten by the build_snapshot method at line 263 in snapshot_builder.rs. This defeated the purpose of the early metadata write, which was intended to preserve the resolved tx_order even if the operation was interrupted.

Solution: Changed the early metadata filename from operation_meta.json to operation_meta_initial.json. This ensures:

The early metadata with the resolved tx_order is preserved even if the operation is interrupted
The file is not silently overwritten by build_snapshot on success
Clear separation between initial intent and final result

Changes: crates/rooch/src/commands/db/commands/state_prune/snapshot.rs:187

Changed: self.output.join("operation_meta.json")
To: self.output.join("operation_meta_initial.json")

2. Review Comment #2728019799: Missing Directory Creation

Problem: The early metadata write attempted to save to the output directory before it was created. The directory creation happens later at line 191 in build_snapshot, causing the early metadata write to fail.

Solution: Added std::fs::create_dir_all(&self.output) before the early metadata write to ensure the output directory exists.

Changes: crates/rooch/src/commands/db/commands/state_prune/snapshot.rs:159-165

Added directory creation with proper error handling before the early metadata save

3. Rust Lint Check Failure

Problem: Code did not match Rust's standard formatting rules, causing the "Rust Lint" check to fail.

Solution: Installed rustfmt component and ran cargo fmt --package rooch to fix all formatting issues.

Result: cargo fmt -- --check now passes without errors.

4. Quick Checks Failure

Problem: The Quick Checks workflow runs cargo fmt -- --check on changed .rs files, which failed due to formatting issues.

Solution: Same as Rust Lint - formatting was fixed using cargo fmt.

Result: Quick Checks formatting validation now passes.

Verification Results

Build Verification

Command: cargo build --bin rooch
Result: ✅ SUCCESS (5m 4s, dev profile)
Notes: Build completed with warnings only (unused variables in unrelated code)

Test Results

Unit Tests

Command: cargo test --package rooch-pruner --lib
Result: ✅ 33/33 tests passed
Duration: 1.03s

Integration Tests

Command: cargo test --package rooch-pruner --test state_prune_tests
Result: ✅ 17/17 tests passed
Duration: 0.00s

Formatting Check

Command: cargo fmt --package rooch -- --check
Result: ✅ PASSED (no formatting violations)

Code Changes

File Modified

crates/rooch/src/commands/db/commands/state_prune/snapshot.rs

Key Changes

Added directory creation (lines 159-165):

// Ensure output directory exists before saving early metadata
std::fs::create_dir_all(&self.output).map_err(|e| {
    rooch_types::error::RoochError::from(anyhow::anyhow!(
        "Failed to create output directory: {}",
        e
    ))
})?;

Changed early metadata filename (line 187):

operation_meta
    .save_to_file(self.output.join("operation_meta_initial.json"))

Updated comments to clarify the design choice:
- Line 167-169: "Write operation_meta_initial.json early with resolved tx_order... Use a different filename so it is not overwritten by build_snapshot"

Impact

Benefits

Early metadata preservation: The resolved tx_order is now safely preserved even if the snapshot operation is interrupted
Proper directory handling: Output directory is created before any file operations, preventing potential failures
Clear separation: Two distinct metadata files serve different purposes:
- operation_meta_initial.json: Captures the initial intent (resolved tx_order) before snapshot building
- operation_meta.json: Final metadata written by build_snapshot upon completion

Backward Compatibility

Changes are fully backward compatible
Existing behavior with explicit --tx-order or --state-root is unchanged
Only improves reliability and debuggability of the snapshot operation

Status

✅ All review comments addressed
✅ All CI check failures resolved
✅ All tests passing
✅ Code properly formatted

PR is ready for merge.

github-actions · 2026-01-26T15:38:54Z

Holon completed successfully.

Run: https://github.com/rooch-network/rooch/actions/runs/21363192760

jolestar

Re-reviewed after latest push:

Output dir creation ✅
Clone/move issue ✅ ( no longer moved because early meta is written to a different file before builder construction)
Acceptance criteria for #3939 now satisfied; metadata is recorded early with resolved tx_order.

Looks good to me.

jolestar

Re-reviewed after latest push:

Output dir creation ✅
Clone/move issue ✅ (snapshot_config no longer moved because early meta is written to a different file before builder construction)
Acceptance criteria for #3939 now satisfied; metadata is recorded early with resolved tx_order.

Looks good to me.

github-actions · 2026-01-26T16:05:41Z

Docker images for this PR are available:

ghcr.io/rooch-network/rooch:pr-3940
ghcr.io/rooch-network/rooch:pr-3940-f6dd83e

Pull commands:

docker pull ghcr.io/rooch-network/rooch:pr-3940
docker pull ghcr.io/rooch-network/rooch:pr-3940-f6dd83e

Fix: Improve snapshot tx_order handling when CLI omits --tx-order

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jolestar requested a review from Copilot January 26, 2026 15:13

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jolestar merged commit 50db5f6 into main Jan 26, 2026
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jolestar deleted the holon/fix-3939-20260126-151132 branch January 26, 2026 16:25

Conversation

holonbot Bot commented Jan 26, 2026

Summary of Changes for Issue #3939

Overview

Changes Made

File: crates/rooch/src/commands/db/commands/state_prune/snapshot.rs

1. Updated CLI Help Text (lines 26-29)

2. Enhanced tx_order Resolution Logic (lines 75-144)

3. Early Metadata Write (lines 156-179)

4. Added Import (line 10)

Acceptance Criteria Verification

Testing Results

Build Verification

Test Commands Run

Impact

Before This Change

After This Change

Backward Compatibility

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holonbot Bot commented Jan 26, 2026

PR #3940 Fix Summary

Overview

Issues Addressed

1. Review Comment #2728019764: Early Metadata Overwrite Issue

2. Review Comment #2728019799: Missing Directory Creation

3. Rust Lint Check Failure

4. Quick Checks Failure

Verification Results

Build Verification

Test Results

Unit Tests

Integration Tests

Formatting Check

Code Changes

File Modified

Key Changes

Impact

Benefits

Backward Compatibility

Status

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File: `crates/rooch/src/commands/db/commands/state_prune/snapshot.rs`

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