docs(adr): ADR-0024 - Prefer explicit foreach over LINQ

[joshsmithxrm]

Status

Proposed

Context

Code scanning tools (CodeQL, Copilot) frequently suggest converting foreach loops with if conditions to LINQ .Where() chains. This creates PR review noise and doesn't improve correctness.

Decision

Prefer explicit foreach loops over LINQ .Where()/.Select() chains for filtering.

Rationale

• Readability: Explicit loops are clearer, especially for complex filtering logic
• Debuggability: Easier to step through and inspect variables
• Maintainability: Easier to add logging, error handling, or additional logic
• Team preference: Confirmed by codebase owner

Exceptions

LINQ is acceptable for:

• Simple one-liners: items.Where(x => x.IsActive).ToList()
• Projection: items.Select(x => x.Name).ToList()
• Method chains: When LINQ reads more naturally (OrderBy, GroupBy, etc.)

Consequences

• Code scanning tools may flag foreach+if patterns
• These warnings should be dismissed as style preference
• See chore: Tune code scanning tools to reduce noise #231 for code scanning tuning

Examples

// Preferred
foreach (var item in items)
{
    if (item.IsActive)
    {
        ProcessItem(item);
    }
}

// Avoid (unless simple one-liner)
foreach (var item in items.Where(x => x.IsActive))
{
    ProcessItem(item);
}

---

Generated with Claude Code

[joshsmithxrm]

Addressed as part of #231:

The cs/linq/missed-where and cs/linq/missed-select CodeQL rules are now disabled in .github/codeql/codeql-config.yml.

Bot instructions in .github/copilot-instructions.md and .gemini/styleguide.md explicitly state:

• Do NOT suggest converting foreach+if to LINQ .Where()
• This is an intentional style preference per project conventions

Note: The ADR number 0024 in the TUI branch refers to Shared Local State Architecture, not this style decision. The foreach-over-LINQ preference is documented in the bot instruction files rather than as a separate ADR.