Fix ambiguous namespace resolution for Sample in bvar::detail

[day253]

Summary

• Fix compilation error in src/braft/util.cpp caused by ambiguous namespace resolution
• Inside namespace bvar::detail, the qualified name detail::Sample<Stat> resolves to bvar::detail::detail::Sample<Stat> which does not exist
• Changed to unqualified Sample<Stat> which correctly resolves to bvar::detail::Sample<Stat>

Background

This issue was discovered when updating the brpc port to 1.16.0 in vcpkg (microsoft/vcpkg#50466). Changes to bvar's internal namespace structure in brpc >= 1.16.0 exposed this pre-existing ambiguity, causing braft to fail to compile.

Changes

--- a/src/braft/util.cpp
+++ b/src/braft/util.cpp
@@ -47,7 +47,7 @@ namespace detail {
 typedef PercentileSamples<1022> CombinedPercentileSamples;
 
 static int64_t get_window_recorder_qps(void* arg) {
-    detail::Sample<Stat> s;
+    Sample<Stat> s;
     static_cast<RecorderWindow*>(arg)->get_span(1, &s);

Test Plan

• Verified braft compiles successfully against brpc 1.16.0 with this fix (via vcpkg CI on all 15 platforms: arm64_android, arm64_linux, arm64_osx, arm64_windows, arm64_windows_static_md, arm_neon_android, x64_android, x64_linux, x64_windows, x64_windows_release, x64_windows_static, x64_windows_static_md, x86_windows)
• See: [brpc] Update to 1.16.0 microsoft/vcpkg#50466

Made with Cursor

[day253]

Hi, this PR fixes the compilation error reported in #524 (braft 1.1.2 incompatibility with brpc 1.16.0).

The fix has been verified across 15 platforms via vcpkg CI: microsoft/vcpkg#50466

@PFZheng @ehds @isaacwong96 Could you please help review this small one-line fix when you have a chance? Thank you! 🙏

cc @simaocat — this should resolve the issue you reported in #524.