fix(scap-targets): enumerate top-level windows instead of desktop children

[matthewdonsemail-lab]

Summary

• Fixes cap targets windows --json returning [] on Windows even when a visible eligible top-level application window is open.
• WindowImpl::list() in crates/scap-targets/src/platform/win.rs was calling EnumChildWindows(Some(GetDesktopWindow()), ...), which enumerates child windows beneath the desktop rather than top-level application windows. Top-level application windows are not discovered this way, so the list came back empty.
• Switches the call to EnumWindows, matching the pattern already used by get_topmost_at_cursor_fallback() in the same file. The callback signature (enum_windows_proc), validity filters (visibility, child/tool-window exclusion, ignored executables, Cap-owned window exclusion), and LPARAM context-passing are unchanged.
• Removes the now-unused EnumChildWindows and GetDesktopWindow imports.

Fixes #2164

Research

A subagent investigation of the Rust coding conventions in this codebase confirmed the fix follows project style:

• Import grouping: std → external crates → local crate, with windows:: modules grouped by hierarchy. Unused imports should be removed (no use windows::Win32::* glob imports).
• No doc comments: the project uses a zero-code-comments-by-default policy; only // line comments are used. This change adds none.
• Unsafe pattern: per-operation unsafe { ... } blocks with let _ = ApiCall(...) for discarded BOOL results — the existing call site already follows this and is preserved.
• Workspace lints: cargo fmt --all and cargo check -p scap-targets both pass clean after the change.

Diff

             WindowsAndMessaging::{
-                DI_FLAGS, DestroyIcon, DrawIconEx, EnumChildWindows, EnumWindows, GCLP_HICON,
-                GW_HWNDNEXT, GWL_EXSTYLE, GWL_STYLE, GetClassLongPtrW, GetClassNameW,
-                GetClientRect, GetCursorPos, GetDesktopWindow, GetIconInfo,
+                DI_FLAGS, DestroyIcon, DrawIconEx, EnumWindows, GCLP_HICON, GW_HWNDNEXT,
+                GWL_EXSTYLE, GWL_STYLE, GetClassLongPtrW, GetClassNameW, GetClientRect,
+                GetCursorPos, GetIconInfo, GetLayeredWindowAttributes, GetWindow,
 ...
         unsafe {
-            let _ = EnumChildWindows(
-                Some(GetDesktopWindow()),
+            let _ = EnumWindows(
                 Some(enum_windows_proc),
                 LPARAM(std::ptr::addr_of_mut!(context) as isize),
             );

Test plan

• On Windows 11, with a visible eligible application window open, cap targets windows --json returns at least one target instead of [].
• The returned target contains a numeric ID corresponding to the native HWND representation used by crates/scap-targets/src/platform/win.rs.
• The ID can be supplied to cap record start --window <id> without requiring pywin32 in the consuming application.
• Invalid, hidden, child, tool, ignored, and Cap-owned windows remain filtered.
• cargo fmt --all -- --check passes.
• cargo check -p scap-targets passes with no warnings.

Greptile Summary

This PR fixes Windows capture-target discovery by replacing desktop-child enumeration with top-level window enumeration while preserving the existing eligibility callback and filters.

• Uses EnumWindows to discover top-level application windows.
• Removes the obsolete EnumChildWindows and GetDesktopWindow imports.
• Keeps the existing callback and LPARAM context-passing behavior unchanged.

Confidence Score: 5/5

The PR appears safe to merge, with no actionable regressions identified in the changed Windows enumeration path.

The new API enumerates the top-level windows required by target listing, while existing downstream validation preserves the intended eligibility constraints.

Important Files Changed

Filename	Overview
crates/scap-targets/src/platform/win.rs	Correctly switches WindowImpl::list() to top-level window enumeration; downstream validation continues to exclude invalid, child, tool, cloaked, system, and Cap-owned targets.

_{Reviews (1): Last reviewed commit: "fix(scap-targets): enumerate top-level w..." | Re-trigger Greptile}

[superagent-security]

Manage your Superagent protection

Superagent has paused scans for this repository because this unlinked GitHub App installation has used all three included PR scans.

You have 0 of 3 included PR scans remaining.

Create a free account to continue protection, manage scan settings, review security history, and control which repositories are protected.