mnesia: replace size/1 by xxx_size/1 #6775
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The <c>size/1</c> BIF is not optimized by the JIT, and its use can result in worse types for Dialyzer. When one knows that the value being tested must be a tuple, <c>tuple_size/1</c> should always be preferred. When one knows that the value being tested must be a binary, <c>byte_size/1</c> should be preferred. However, <c>byte_size/1</c> also accepts a bitstring (rounding up size to a whole number of bytes), so one must make sure that the call to <c>byte_size/</c> is preceded by a call to <c>is_binary/1</c> to ensure that bitstrings are rejected. Note that the compiler removes redundant calls to <c>is_binary/1</c>, so if one is not sure whether previous code had made sure that the argument is a binary, it does not harm to add an <c>is_binary/1</c> test immediately before the call to <c>byte_size/1</c>.
49 tasks
Contributor
CT Test ResultsTests are running... https://github.com/erlang/otp/actions/runs/4074055616 Results for commit 8560843 To speed up review, make sure that you have read Contributing to Erlang/OTP and that all checks pass. See the TESTING and DEVELOPMENT HowTo guides for details about how to run test locally. Artifacts
// Erlang/OTP Github Action Bot |
dgud
approved these changes
Feb 3, 2023
Contributor
Author
|
Super-seeded by #6785 due to a branch name change. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The size/1 BIF is not optimized by the JIT, and its use can result in worse types for Dialyzer.
When one knows that the value being tested must be a tuple, tuple_size/1 should always be preferred.
When one knows that the value being tested must be a binary, byte_size/1 should be preferred. However, byte_size/1 also accepts a bitstring (rounding up size to a whole number of bytes), so one must make sure that the call to byte_size/ is preceded by a call to is_binary/1 to ensure that bitstrings are rejected. Note that the compiler removes redundant calls to is_binary/1, so if one is not sure whether previous code had made sure that the argument is a binary, it does not harm to add an is_binary/1 test immediately before the call to byte_size/1.