Backport release/v6.7: Validate snapshots before publication

[seidroid]

Backport of #4036 to release/v6.7.

[cursor]

PR Summary

High Risk
Changes critical state persistence (snapshot publication, current symlink, and empty-DB initialization) where mistakes could cause data loss or silent reset; behavior is defensive but touches core node storage paths.

Overview
Hardens MemIAVL snapshot rewrite and startup so corrupt on-disk snapshots are detected and replaced safely, while transient failures (cancelled context, permissions) never delete a good current target.

Introduces errCorruptedSnapshot and threads it through metadata load, mmap layout checks, and validateSnapshot (reload + match multi-tree version, store set, per-store version, and root hash against lastCommitInfo). RewriteSnapshot / publishSnapshot validate before skip, adopt, or replace; a corrupted target is removed only after a validated -tmp directory exists.

Startup: createDBIfNotExist refuses to silently initEmptyDB when current is a dangling symlink. Write path: snapshot writer rejects non-32-byte node hashes. LoadMultiTree closes partially opened trees on failed load.

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[codecov]

Codecov Report

❌ Patch coverage is 71.92982% with 32 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.61%. Comparing base (5eb099e) to head (aa44ba7).

Files with missing lines	Patch %	Lines
sei-db/state_db/sc/memiavl/db.go	74.71%	12 Missing and 10 partials ⚠️
sei-db/state_db/sc/memiavl/multitree.go	61.53%	3 Missing and 2 partials ⚠️
sei-db/state_db/sc/memiavl/snapshot.go	64.28%	5 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release/v6.7    #4054      +/-   ##
================================================
- Coverage         61.33%   60.61%   -0.73%     
================================================
  Files              2163     2083      -80     
  Lines            188823   180280    -8543     
================================================
- Hits             115813   109274    -6539     
+ Misses            62286    60984    -1302     
+ Partials          10724    10022     -702     

Flag	Coverage Δ
sei-db	69.80% <ø> (ø)
sei-db-state-db	?
sei-db-state-db-pr	77.13% <71.92%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sei-db/state_db/sc/memiavl/multitree.go	80.76% <61.53%> (+1.37%)	⬆️
sei-db/state_db/sc/memiavl/snapshot.go	67.70% <64.28%> (+1.94%)	⬆️
sei-db/state_db/sc/memiavl/db.go	69.86% <74.71%> (+3.43%)	⬆️

... and 82 files with indirect coverage changes

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[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Aug 28, 2026, 4:13 PM

[seidroid]

The automated review did not complete; see the failing AI Review check for details.

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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[cursor]

Snapshot replacement can orphan current

High Severity

When replacing a corrupted snapshot, publishSnapshot removes the existing target before the validated temp is renamed into place. A failed second rename or a crash in that window, then cleanupFailedSnapshotRewrite, deletes the replacement too and leaves current dangling. createDBIfNotExist then refuses to open the store.

Additional Locations (1)

• sei-db/state_db/sc/memiavl/db.go#L821-L823

 

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