fix zero initial size for memory resource parent

[pknowles]

Summary by CodeRabbit

• New Features

  • Enhanced memory allocation logic to prevent unnecessary allocations when the requested size is zero.
  • Improved test coverage for the memory resource with new test cases addressing various allocator types and initialization scenarios.

• Bug Fixes

  • Addressed potential null pointer issues by implementing defensive allocation checks.

[coderabbitai]

Walkthrough

The pull request modifies the linear_memory_resource constructor to include a conditional check for the initialSize parameter, preventing unnecessary memory allocation when it is zero. Additionally, new test cases are introduced to enhance the testing of the linear_memory_resource class, particularly focusing on its behavior with different allocator types and zero initialization scenarios. The changes aim to improve the robustness and correctness of memory management within the class.

Changes

Files	Change Summary
include/decodeless/allocator.hpp	Updated linear_memory_resource constructor to check initialSize before allocation.
test/src/allocator.cpp	Renamed EmptyRealloc to EmptyReallocDefault and added new tests: EmptyRealloc, ZeroInitialRealloc, and ZeroInitialReallocMemoryResource.

Possibly related PRs

• test realloc behaviour and allocator equality #3: This PR relates to the new test cases added that specifically test the behavior of linear_memory_resource, including scenarios with zero initial size.
• Fix compilation on Visual Studio 2019 v16.11.42 #8: This PR involves modifications to the constructors of the linear_memory_resource class, which is relevant to the changes in the main PR.
• header split, cleanup and new tests #2: This PR addresses the linear_memory_resource class, specifically regarding its allocation logic and member functions, connecting to the changes made in the main PR.

Poem

In the land of memory, where bunnies roam,
A check was added to make it feel like home.
No more wasted space, just a hop and a skip,
With tests to ensure no memory slip.
So let’s celebrate, with a twitch of the nose,
For robust allocations, our joy only grows! 🐇✨

---

📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: ASSERTIVE
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 5312009 and 9b45b23.

📒 Files selected for processing (2)

• include/decodeless/allocator.hpp (1 hunks)
• test/src/allocator.cpp (1 hunks)

⏰ Context from checks skipped due to timeout of 90000ms (1)

• GitHub Check: build (windows-latest, Release, cl)

🔇 Additional comments (4)

include/decodeless/allocator.hpp (1)

82-82: LGTM! Good optimization for zero-size allocation.

The change to prevent allocation when initialSize is zero is a good optimization. This avoids unnecessary memory allocation calls and aligns with best practices.

test/src/allocator.cpp (3)

212-216: LGTM! Good test coverage for memory resource initialization.

Test case verifies that a memory resource with zero initial size is correctly initialized with zero size and capacity.

---

218-222: LGTM! Good test coverage for allocator initialization.

Test case verifies that an allocator with zero initial size is correctly initialized with zero size and capacity.

---

224-228: LGTM! Good test coverage for memory resource parent initialization.

Test case verifies that a memory resource parent with zero initial size is correctly initialized with zero size and capacity.

✨ Finishing Touches

• 📝 Generate Docstrings (Beta)

---

Thank you for using CodeRabbit. We offer it for free to the OSS community and would appreciate your support in helping us grow. If you find it useful, would you consider giving us a shout-out on your favorite social media?

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

🪧 Tips

Chat

There are 3 ways to chat with CodeRabbit:

• Review comments: Directly reply to a review comment made by CodeRabbit. Example:
  • I pushed a fix in commit <commit_id>, please review it.
  • Generate unit testing code for this file.
  • Open a follow-up GitHub issue for this discussion.
• Files and specific lines of code (under the "Files changed" tab): Tag @coderabbitai in a new review comment at the desired location with your query. Examples:
  • @coderabbitai generate unit testing code for this file.
  • @coderabbitai modularize this function.
• PR comments: Tag @coderabbitai in a new PR comment to ask questions about the PR branch. For the best results, please provide a very specific query, as very limited context is provided in this mode. Examples:
  • @coderabbitai gather interesting stats about this repository and render them as a table. Additionally, render a pie chart showing the language distribution in the codebase.
  • @coderabbitai read src/utils.ts and generate unit testing code.
  • @coderabbitai read the files in the src/scheduler package and generate a class diagram using mermaid and a README in the markdown format.
  • @coderabbitai help me debug CodeRabbit configuration file.

Note: Be mindful of the bot's finite context window. It's strongly recommended to break down tasks such as reading entire modules into smaller chunks. For a focused discussion, use review comments to chat about specific files and their changes, instead of using the PR comments.

CodeRabbit Commands (Invoked using PR comments)

• @coderabbitai pause to pause the reviews on a PR.
• @coderabbitai resume to resume the paused reviews.
• @coderabbitai review to trigger an incremental review. This is useful when automatic reviews are disabled for the repository.
• @coderabbitai full review to do a full review from scratch and review all the files again.
• @coderabbitai summary to regenerate the summary of the PR.
• @coderabbitai generate docstrings to generate docstrings for this PR. (Beta)
• @coderabbitai resolve resolve all the CodeRabbit review comments.
• @coderabbitai configuration to show the current CodeRabbit configuration for the repository.
• @coderabbitai help to get help.

Other keywords and placeholders

• Add @coderabbitai ignore anywhere in the PR description to prevent this PR from being reviewed.
• Add @coderabbitai summary to generate the high-level summary at a specific location in the PR description.
• Add @coderabbitai or @coderabbitai title anywhere in the PR title to generate the title automatically.

CodeRabbit Configuration File (.coderabbit.yaml)

• You can programmatically configure CodeRabbit by adding a .coderabbit.yaml file to the root of your repository.
• Please see the configuration documentation for more information.
• If your editor has YAML language server enabled, you can add the path at the top of this file to enable auto-completion and validation: # yaml-language-server: $schema=https://coderabbit.ai/integrations/schema.v2.json

Documentation and Community

• Visit our Documentation for detailed information on how to use CodeRabbit.
• Join our Discord Community to get help, request features, and share feedback.
• Follow us on X/Twitter for updates and announcements.