case113 — internal function-template signature leaks via public API (BREAKING)

Field	Value
Verdict	🔴 BREAKING
Category	Breaking
Platforms	Linux, macOS, Windows
Flags	ABI break
Detected ChangeKinds	internal_template_leaks_via_public_api, func_removed
Source files	browse on GitHub

What this case demonstrates

The function-template analogue of PR #238's type leak detection. A helper template lives in lib::__detail:: — conceptually private — but a public inline algorithm dispatches to it, so every consumer's symbol table contains an instantiation of the "internal" template.

v1 ships	v2 ships
__detail::walk<int>, __detail::walk<float>	__detail::walk<int>, __detail::walk<double>

A consumer that wrote lib::sum_range<float>(...) linked against v1 ends up needing __detail::walk<float>; against v2 that symbol no longer exists.

Why a dedicated finding

A plain func_removed for __detail::walk<float> invites the dismissal "that's internal, ignore it". INTERNAL_TEMPLATE_LEAKS_VIA_PUBLIC_API makes the leak path explicit and aggregates the per-instantiation churn into a single finding per stem.

Expected verdict

BREAKING — consumers fail to link or load.

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Source files

• CMakeLists.txt
• app.cpp
• v1.cpp
• v1.h
• v2.cpp
• v2.h

See also: Examples overview · All BREAKING cases · Category: Breaking.