Fix for missing results

[wwpreston]

This PR suggests a fix for an issue some users are experiencing where results are missing from the 'problems' window in VS Code (#223).

Summary

There is loop with range i to -1 that I think should be i to 0 (inclusive).

Details

Sometimes linters (specifically cppcheck) return output for multiple files when asked to evaluate a specific file (e.g. evaluating a .c file returns issues with included .h files).

A loop in server.ts processes the results.
It loops over the array processing 1 file in each iteration.
After processing a result it is removed from the list (result.splice(i, 1)).
Eventually the list is empty.

There appears to be a bug with the loop range.
In while (i-- >= 0) variable i has range result.length-1 to -1 inclusive.
When i is -1 it can remove a result from the list that is not marked for the current file (result.splice(-1, 1)).
This causes missing items in the 'problems' window in VS Code.

Proposed fix: change the loop to while (--i >= 0), then variable i has range result.length-1 to 0 inclusive.

Simplified example

This is a simplified example of the loop in server.ts.

let result = [
	{ file: 'file1.h', issue: 'Issue A' },
	{ file: 'file1.h', issue: 'Issue B' },
	{ file: 'file2.h', issue: 'Issue C' },
	{ file: 'file2.h', issue: 'Issue D' },
	{ file: 'file3.c', issue: 'Issue E' },
	{ file: 'file3.c', issue: 'Issue F' },
];

while (result.length > 0) {
	let currentFile = '';
	let i = result.length;
	while (--i >= 0) {
		let msg = result[i];
		
		if (msg === null || msg === undefined || msg.parseError || msg.source === '') {
			result.splice(i, 1);
			continue;
		}
		
		if (currentFile === '') {
			currentFile = msg.file;
		}
		
		if (currentFile !== msg.file) {
			continue;
		}
		
		console.log("Processed result: file="+msg.file+" issue="+msg.issue);
		result.splice(i, 1);
	}
}

Output with while (i-- >= 0) (misses 2 items):

Processed result: file=file3.c issue=Issue F
Processed result: file=file3.c issue=Issue E
Processed result: file=file2.h issue=Issue C
Processed result: file=file1.h issue=Issue A

Output with while (--i >= 0):

Processed result: file=file3.c issue=Issue F
Processed result: file=file3.c issue=Issue E
Processed result: file=file2.h issue=Issue D
Processed result: file=file2.h issue=Issue C
Processed result: file=file1.h issue=Issue B
Processed result: file=file1.h issue=Issue A

Hotfix

You can easily apply this change to the release version (1.15.0) of the extension.

1. Open the following file:

   • ~/.vscode/extensions/jbenden.c-cpp-flylint-1.15.0/server/out/server.js
     • If you're using a VSCode on a remote server .vscode might be .vscode-remote or .vscode-server.

2. Find:

for(;r-- >=0;){let i=e[r];if(null==i||i.parseError||!i.hasOwnProperty("line")||""===i.source){e.splice(r,1);continue}

3. Replace with:

for(;--r >=0;){let i=e[r];if(null==i||i.parseError||!i.hasOwnProperty("line")||""===i.source){e.splice(r,1);continue}

4. Restart VS Code.

[fr43nk]

@wwpreston it seems that the maintainer of this extension no longer is active in any way. The github activity is empty since almost a year. I also tried to reach him via email.
If you want, I can create a fork of this an try to keep the extension alive with a new name in the marketplace and your fix can be implemented into the sources. Please have a look here: https://github.com/fr43nk/vscode-lint-for-cpp