Fix miscalculation of tree size in concurrent editing

[hackerwins]

What this PR does / why we need it?

Fix miscalculation of tree size in concurrent editing

This commit addresses the issue where the updateAncestorsSize method
subtracts the size of a tombstoned node from its ancestors' sizes when
the node is removed. However, the previous logic did not consider
cases where ancestors node are tombstoned. In such cases, the update
should not propagate to the parent's ancestors. This commit introduces
recursive checks on ancestors and stops updating process if a
tombstoned ancestor is encountered.

Furthermore, the PR ensures consistency between the size maintenance
policies of updateDescendantsSize and updateAncestorsSize.

Any background context you want to provide?

What are the relevant tickets?

Address yorkie-team/yorkie#889

Checklist

• Added relevant tests or not required
• Didn't break anything

Summary by CodeRabbit

• Bug Fixes

  • Improved accuracy in size calculations when child nodes are removed in the index tree.

• Tests

  • Added new test cases for concurrent editing and snapshot consistency of the index tree.

[coderabbitai]

Walkthrough

The recent updates streamline the logic for managing tree structures in the codebase. Specifically, the CRDTTreeNode class in tree.ts now has a simplified method for updating ancestor sizes, while the IndexTreeNode class in index_tree.ts has improved handling of descendant sizes when child nodes are removed. Additionally, new test cases have been added to ensure the integrity of index tree size calculations during concurrent editing and snapshots.

Changes

File Path	Change Summary
src/document/crdt/tree.ts	Simplified the logic for updating ancestors' size in CRDTTreeNode by directly calling updateAncestorsSize() when alived.
src/util/index_tree.ts	Modified updateDescendantsSize method in IndexTreeNode to handle child node removal for accurate size calculations.
test/integration/tree_test.ts	Added imports for converter and toXML, and new test cases for index tree size calculations during concurrent editing and snapshot consistency.

Poem

In the land of code, where trees do grow,
Ancestors and descendants now flow,
With logic refined, sizes align,
Concurrent edits, tests combine.
The forest stands tall, in harmony,
A testament to code's symphony. 🌳🐇

---

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.68%. Comparing base (9e12b9e) to head (896a868).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #846   +/-   ##
=======================================
  Coverage   80.68%   80.68%           
=======================================
  Files          59       59           
  Lines        4586     4586           
  Branches      932      932           
=======================================
  Hits         3700     3700           
  Misses        617      617           
  Partials      269      269           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[coderabbitai]

Actionable comments posted: 1

Outside diff range and nitpick comments (2)

src/document/crdt/tree.ts (2)

Line range hint 727-727: Consider using optional chaining for better safety and readability.

- if (parentNode.isRemoved) {
+ if (parentNode?.isRemoved) {

This change will prevent potential runtime errors if parentNode is null or undefined.

---

Line range hint 1533-1533: Remove unnecessary return statement in a void function.

- return this.indexTree.tokensBetween(fromIdx, toIdx, callback);
+ this.indexTree.tokensBetween(fromIdx, toIdx, callback);

The traverseInPosRange method is declared to return void, so any return statement within it should be removed to avoid confusion and adhere to TypeScript's type expectations.

Review details

Configuration used: CodeRabbit UI
Review profile: CHILL

Commits

Files that changed from the base of the PR and between 2305dbc and 896a868.

Files selected for processing (3)

• src/document/crdt/tree.ts (1 hunks)
• src/util/index_tree.ts (2 hunks)
• test/integration/tree_test.ts (3 hunks)

Additional context used

Biome

src/document/crdt/tree.ts

[error] 727-727: Change to an optional chain. (lint/complexity/useOptionalChain)

Unsafe fix: Change to an optional chain.

---

[error] 1533-1533: The function should not return a value because its return type is void. (lint/correctness/noVoidTypeReturn)

The function is here:

'void' signals the absence of value. The returned value is likely to be ignored by the caller.

test/integration/tree_test.ts

[error] 33-75: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 77-108: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 110-135: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 137-194: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 196-244: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 246-316: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 318-407: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 409-507: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 509-541: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 543-579: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 581-617: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 619-676: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 680-704: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 706-733: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 735-847: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 849-873: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 875-899: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 901-931: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 933-957: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

---

[error] 959-983: This function expression can be turned into an arrow function. (lint/complexity/useArrowFunction)

Function expressions that don't use this can be turned into arrow functions.
Safe fix: Use an arrow function instead.

Additional comments not posted (5)

src/util/index_tree.ts (1)

146-149: Ensure proper handling of removed parent nodes in updateAncestorsSize.

src/document/crdt/tree.ts (1)

553-553: Ensure correct ancestor size update logic.

The change to directly call updateAncestorsSize() when a node is marked as removed ensures that the tree size is recalculated immediately, which is crucial for maintaining accurate tree metrics during concurrent modifications.

test/integration/tree_test.ts (3)

18-18: LGTM! The addition of converter aligns with the changes described in the PR.

---

30-30: LGTM! The addition of toXML aligns with the changes described in the PR.

---

4126-4212: LGTM! The test case effectively checks the size calculations and consistency of the index tree during concurrent editing, aligning with the PR's objectives.