Windows Coverage GitHub workflow broken

[richardlau]

https://github.com/nodejs/node/actions/workflows/coverage-windows.yml has started failing for main and v24.x-staging.

src\hdr_histogram.c(149,23): error : incompatible pointer types passing 'uint32_t *' (aka 'unsigned int *') to parameter of type 'unsigned long *' [-Wincompatible-pointer-types] [D:\a\node\node\deps\histogram\histogram.vcxproj]

Previously this was treated as a warning:

src\hdr_histogram.c(149,23): warning : incompatible pointer types passing 'uint32_t *' (aka 'unsigned int *') to parameter of type 'unsigned long *' [-Wincompatible-pointer-types] [D:\a\node\node\deps\histogram\histogram.vcxproj]

Failing runs:

• https://github.com/nodejs/node/actions/runs/27763770312/job/82144796596
• https://github.com/nodejs/node/actions/runs/27756607694/job/82119935343?pr=62407
• https://github.com/nodejs/node/actions/runs/27758928460/job/82127895098?pr=63834

Passing runs:

• https://github.com/nodejs/node/actions/runs/27736774550/job/82055134854

It looks like this might be because the GitHub Windows 2025 runners have newer versions of Visual Studio 2026:

Histogram warnings:

Visual Studio 2026 Developer Command Prompt v18.6.2

Histogram errors:

Visual Studio 2026 Developer Command Prompt v18.7.0

FWIW we're still running on VS 2022 in our Jenkins CI where we see the warnings.

[richardlau]

It looks like the unofficial gni file for deps/histogram suppresses some warnings that we currently do not do in our gyp scripts:

node/deps/histogram/unofficial.gni

Lines 21 to 27 in f6156ce

	if (is_clang || !is_win) {
	cflags_c = [
	"-Wno-atomic-alignment",
	"-Wno-incompatible-pointer-types",
	"-Wno-unused-function",
	]
	}

I've opened #63980 to see if mirroring those into the gyp scripts gets the coverage workflow building again on the newer VS 2026.