Implement C Declarations6 package

[knewbury01]

Description

Add Decl6

Change request type

• Release or process automation (GitHub workflows, internal scripts)
• Internal documentation
• External documentation
• Query files (.ql, .qll, .qls or unit tests)
• External scripts (analysis report or other code shipped as part of a release)

Rules with added or modified queries

• No rules added
• Queries have been added for the following rules:
  • RULE-17-3
  • RULE-5-8
  • RULE-5-9
  • RULE-8-7
  • RULE-8-10
  • RULE-8-11
  • RULE-18-7
• Queries have been modified for the following rules:
  • rule number here

Release change checklist

A change note (development_handbook.md#change-notes) is required for any pull request which modifies:

• The structure or layout of the release artifacts.
• The evaluation performance (memory, execution time) of an existing query.
• The results of an existing query in any circumstance.

If you are only adding new rule queries, a change note is not required.

Author: Is a change note required?

• Yes
• No

Reviewer: Confirm that either a change note is not required or the change note is required and has been added.

• Confirmed

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

• Have all the relevant rule package description files been checked in?
• Have you verified that the metadata properties of each new query is set appropriately?
• Do all the unit tests contain both "COMPLIANT" and "NON_COMPLIANT" cases?
• Are the alert messages properly formatted and consistent with the style guide?
• Have you run the queries on OpenPilot and verified that the performance and results are acceptable?
  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.
• Does the query have an appropriate level of in-query comments/documentation?
• Have you considered/identified possible edge cases?
• Does the query not reinvent features in the standard library?
• Can the query be simplified further (not golfed!)

Reviewer

• Have all the relevant rule package description files been checked in?
• Have you verified that the metadata properties of each new query is set appropriately?
• Do all the unit tests contain both "COMPLIANT" and "NON_COMPLIANT" cases?
• Are the alert messages properly formatted and consistent with the style guide?
• Have you run the queries on OpenPilot and verified that the performance and results are acceptable?
  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.
• Does the query have an appropriate level of in-query comments/documentation?
• Have you considered/identified possible edge cases?
• Does the query not reinvent features in the standard library?
• Can the query be simplified further (not golfed!)

[knewbury01]

Notes RULE-17-3

The description also talks a bit about function prototypes (which are inherently not implicit declarations) however I think checking that in this rule would be too strict of an interpretation, and function prototype usage is already covered in RULE-8-2 anyways.

[knewbury01]

Notes RULE-5-9

I omitted consideration of the exception case, "Inline functions with internal linkage may be defined in more than one translation unit if they are in the same header file" - this isnt really relevant to CodeQL bc the database only includes one Declaration in this case either way, so re-adding the duplicate detection across multiple translation units then re-removing it makes no sense.

Plus if we think about it, what would the action item be for: "a declaration has the same name - in the same file - just across multiple translation units"... make sure no file could be used in multiple translation units? that wouldnt make sense to me at least.

[knewbury01]

Notes RULE-8-10

I have opted for the most strict implementation of this rule so far. The rule title says the most strict fix, but the rationale describes how the undefined behaviour actually only occurs in a specific subset of cases when an inline function omits the static storage class. I can take another look if it currently actually seems too strict.

[nicolaswill]

Completely agree on the rationale for both of your implementation notes 👍 RULE-5-9 is extremely noisy as-is though; I'm still wondering if there is a more useful interpretation of the rule.

LGTM other than missing implementation notes and a suggestion for preventing permutations in RULE-5-9.