Update EXP43-C to use new dataflow. - #1204
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MichaelRFairhurst wants to merge 2 commits into
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MichaelRFairhurst wants to merge 2 commits into
MichaelRFairhurst wants to merge 2 commits into
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Updating to new dataflow introduced test failures in the old test.c file caused by an assignment that aliased the two primary global values under test. Most of the test assumed these were distinct pointer values, and yet, there was one assignment between them, contradicting this intention. The old dataflow library seemed to model this as a function called once, which would produce the results that the test expected. However, the new dataflow seems to assume that the function could be called multiple times, and therefore the fact that these globals were ever aliased means they have flow between them. Broke the main test function apart into separate functions testing against separate global values, to preserve old test results as much as possible, and cleanly exercise the new justifiable difference in behavior.
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Copilot review overview
🟡 Changes recommended
The migration introduces duplicate alerts for individual violations, and one test explanation reverses the assignment direction.
Review effort: Balanced
Findings: 1
Open (2)
What changed in this PR
Migrates EXP43-C to CodeQL’s new dataflow library and updates tests for changed global-flow behavior.
Changes:
- Replaces the deprecated dataflow import.
- Separates global-pointer test scenarios and updates expected results.
- Adds the required change note.
- Unverified: VS Code shared-query validation and OpenPilot performance.
| File | Description |
|---|---|
change_notes/2026-10-01-use-new-dataflow-in-exp43-c.md |
Documents the migration and result changes. |
c/cert/src/rules/EXP43-C/RestrictPointerReferencesOverlappingObject.ql |
Uses the new dataflow library. |
c/cert/test/rules/EXP43-C/test.c |
Separates global aliasing scenarios. |
c/cert/test/rules/EXP43-C/RestrictPointerReferencesOverlappingObject.expected |
Updates expected alerts for new flow behavior. |
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| | test.c:49:10:49:11 | g5 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:45:19:45:20 | i5 | i5 | test.c:41:22:41:23 | g5 | the same source value | | ||
| | test.c:49:10:49:11 | g5 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:45:19:45:20 | i5 | i5 | test.c:47:10:47:11 | g5 | the same source value | |
| // | ||
| // If we assume that `test_global_local_2` is only called once, then `g3` and | ||
| // `g4` will likely point to different values and therefore `i1` and `i2` do | ||
| // not alias each other. from g3 to g4 is too late to cause an issue. This was |
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Description
Updating to new dataflow introduced test failures in the old test.c file caused by an assignment that aliased the two primary global values under test. Most of the test assumed these were distinct pointer values, and yet, there was one assignment between them, contradicting this intention. The old dataflow library seemed to model this as a function called once, which would produce the results that the test expected. However, the new dataflow seems to assume that the function could be called multiple times, and therefore the fact that these globals were ever aliased means they have flow between them.
Broke the main test function apart into separate functions testing against separate global values, to preserve old test results as much as possible, and cleanly exercise the new justifiable difference in behavior.
Change request type
.ql,.qll,.qlsor unit tests)Rules with added or modified queries
EXP43-CRelease change checklist
A change note (development_handbook.md#change-notes) is required for any pull request which modifies:
If you are only adding new rule queries, a change note is not required.
Author: Is a change note required?
🚨🚨🚨
Reviewer: Confirm that format of shared queries (not the .qll file, the
.ql file that imports it) is valid by running them within VS Code.
Reviewer: Confirm that either a change note is not required or the change note is required and has been added.
Query development review checklist
For PRs that add new queries or modify existing queries, the following checklist should be completed by both the author and reviewer:
Author
As a rule of thumb, predicates specific to the query should take no more than 1 minute, and for simple queries be under 10 seconds. If this is not the case, this should be highlighted and agreed in the code review process.
Reviewer
As a rule of thumb, predicates specific to the query should take no more than 1 minute, and for simple queries be under 10 seconds. If this is not the case, this should be highlighted and agreed in the code review process.