[SAOC 2024] Improve D Error Messages - Weekly Update #5

[Royal Simpson Pinto]

## Summary of Progress (October 14 – October 20)

This week, I focused on addressing feedback and adding tests for 
SARIF (Static Analysis Results Interchange Format) support in the 
DMD compiler. The current PR introduces a `--sarif` compiler flag 
to generate structured SARIF output for error messages.

**PR:** [feat(errors): add SARIF report generation 
#16986](https://github.com/dlang/dmd/pull/16986)

### What I Worked On:

- **Adding Tests and Addressing Feedback**
   I spent time this week addressing the feedback provided on my 
PR, particularly refining the SARIF implementation. I added a 
test case to validate the output and ensure the correctness of 
SARIF reports.

- **Handling Regex Matching for Variable Outputs**
   I encountered issues with matching variable outputs in test 
pipelines versus local outputs. After multiple attempts to 
resolve these through regexes, I decided to implement a simpler 
version of the SARIF report, excluding certain complexities such 
as relative paths, to avoid complications.

- **Milestone 1 Report Preparation**
   I also dedicated time to finalizing and submitting my Milestone 
1 report, which summarizes the progress from September 15 to 
October 14, 2024.

- **Exploring Milestone 2 Tasks**
   I began exploring the objectives of Milestone 2, which involve 
enhancing error message utilities such as adding more detailed 
squiggles and error codes. I reviewed the existing utilities and 
documentation to understand how error codes and squiggles are 
currently implemented in the DMD compiler.

### Challenges:

- **PR Merge**
   I had hoped my PR would be merged this week, which would allow 
me to start working on additional updates like using 
`MessageStyle` for SARIF output instead of a compiler flag. 
However, the merge is still pending, which is currently blocking 
me from making further progress on SARIF-related updates. 
Although the PR has been approved by one maintainer, it still 
needs to be merged.

- **Resolving Regex Issues**
   The most significant challenge was handling regexes to match 
variable outputs between local tests and CI pipelines. 
Ultimately, I simplified the SARIF version to avoid complexities 
related to relative paths and other variable outputs.

### Next Steps:

- **MessageStyle Implementation**
   Once the current PR is merged, I plan to work on implementing 
SARIF using `MessageStyle`, which will be done in a separate PR.

- **Further Exploration of Milestone 2**
   I will continue researching the error message utilities and 
explore how to integrate more detailed squiggles and error codes 
into the compiler. Any links to existing Bugzilla issues 
(specifically related to this) or resources would be really 
helpful.

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