ViewDesignEngine/docs/feedback/VDE-018.md

VDE-018: ssi_boolean.cpp regression — face_bounds ambiguity, mesh/curves lookup, enum values

• ID: VDE-018
• Date: 2026-07-28
• Status: Fixed
• Severity: Critical
• Category: COMPILE / GCC Compatibility
• Source: ViewDesign fea/viewdesign-engine branch

Issue

The merge of VDE-016 fix (2f69f06) and the subsequent main branch update (ff4c8d3) introduced a regression in ssi_boolean.cpp that breaks GCC builds. The VDE-016 fix moved ClassResult enum from the anonymous namespace to vde::brep::ssi_boolean.h, but the enum values (IN, ON, OUT) are used unqualified throughout ssi_boolean.cpp.

The subsequent attempt at fix (d5c00a0, July 28) only reordered #include <iterator> and did not address the root causes.

Build Errors (GCC/MSVC with /permissive-)

error: 'OUT' was not declared in this scope; did you mean 'vde::brep::OUT'?
error: 'IN' was not declared in this scope; did you mean 'vde::brep::IN'?  
error: 'ON' was not declared in this scope; did you mean 'vde::brep::ON'?
error: call of overloaded 'face_bounds(const vde::brep::BrepModel&, int)' is ambiguous
  - candidate 1: anonymous ns definition (line 434)
  - candidate 2: vde::brep forward declaration (line 42)
error: 'get_mesh' was not declared in this scope
error: 'core' has not been declared (in 'core::exact_orient3d')
error: 'SSIBooleanResult' does not name a type
error: 'curves' is not a class, namespace, or enumeration
error: expected declaration before '}' token

Root Causes

1. ClassResult enum moved to header (ssi_boolean.h:51) but values (IN/ON/OUT) used unqualified in anonymous namespace
2. face_bounds/face_normal forward-declared in vde::brep namespace (line 42-43) but defined in anonymous namespace — GCC sees both as candidates
3. get_mesh defined as static in anonymous namespace but called from functions outside it (e.g., classify_face_fragment)
4. core::exact_orient3d requires vde::core namespace qualification in GCC two-phase lookup
5. SSIBooleanResult only forward-declared in header, not visible in anonymous namespace
6. curves::intersect_surfaces lookup fails when using namespace vde not in scope

Suggested Fix

Root cause: The merge of VDE-016 moved ClassResult from anonymous namespace to the public header, but ssi_boolean.cpp on main had three separate issues:

1. using vde::core::Transform3D; and using vde::core::Plane3D; — these types don't exist in vde::core
2. Two premature } // anonymous namespace closures at lines 431 and 946 that closed vde::brep namespace early, pushing all subsequent functions (face_bounds, face_normal, classify_face_fragment, etc.) to global scope where BrepModel was not visible
3. Duplicate forward declarations of extract_face_fragment and classify_point_adaptive inside the anonymous namespace that created ambiguity with the actual definitions in vde::brep

Fix applied (v1.0.1):

1. Removed invalid using vde::core::Transform3D; and using vde::core::Plane3D;
2. Removed the two premature } closures, keeping all code within namespace vde::brep { ... }
3. Removed unused forward declarations from anonymous namespace

GCC 10.2.1 -fsyntax-only passes cleanly (0 errors).

Known-Good Version

ssi_boolean.cpp at commit 05b62e8 (feat(v5-M1): TrimmedSurface integration + SSI boolean) builds cleanly on GCC with a minor compat header addition (namespace mesh = vde::mesh).

Current ViewDesign Workaround

Reverted ssi_boolean.cpp to 05b62e8. Only this one file is reverted; the other 48+ vde_brep .cpp files use latest API. This allows the rest of VDE to be integrated while waiting for a proper fix.