xkbcomp: Fix incorrect memory comparison #661
Merged
Conversation
This file contains 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
Spotted by clang-tidy:
```
../src/keymap-priv.c:146:16: warning: comparing object representation of
type 'union xkb_action' which does not have
a unique object representation; consider
comparing the members of the object manually
[bugprone-suspicious-memory-comparison]
````
Indeed, from “EXP42-C. Do not compare padding data”[^1]:
> unnamed members of objects of structure and union type do not participate
> in initialization. Unnamed members of structure objects have indeterminate
> representation even after initialization.
Fixed by using a dedicated comparison function for `union xkb_action`.
[^1]: https://wiki.sei.cmu.edu/confluence/display/c/EXP42-C.+Do+not+compare+padding+data
wismill
added
the
compiler warning
Merged
bluetech
approved these changes
Feb 14, 2025
| if (a->type != b->type) | ||
| return false; | ||
|
|
||
| /* Ensure we support all action types */ |
There was a problem hiding this comment.
That’s a minimal safeguard against changes in the actions types, but I do not know how to check if we were to add new fields. Well, this kind of refactor is unlikely, but who knows?
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
Spotted by
clang-tidy:Indeed, from “EXP42-C. Do not compare padding data”1:
But since we zero the action, I do not think the current behavior can cause a bug, can it?
Fixed by using a dedicated comparison function for
union xkb_action.Footnotes
https://wiki.sei.cmu.edu/confluence/display/c/EXP42-C.+Do+not+compare+padding+data ↩