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[Minor Feature] Instrumented libtcod debug build for sanitizer coverage #280

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opened 2026-03-08 03:19:35 +00:00 by john · 0 comments
john commented 2026-03-08 03:19:35 +00:00
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Context

The debug build system (added post-7DRL 2026) instruments McRogueFace code with ASan/UBSan, but libtcod's pre-built release binaries in __lib/ are uninstrumented. libtcod's pathfinding and FOV operate directly on McRogueFace's grid data structures — the exact location of the #258–#263 heap overflow family.

ASan can detect overflows in our code that corrupt their memory, but cannot detect bugs originating inside libtcod. Since we build libtcod from source anyway (modules/libtcod-headless/), adding an instrumented build is straightforward.

Proposal

Add libtcod to tools/build_debug_python.sh (or a companion tools/build_debug_libs.sh) that:

  1. Builds libtcod from modules/libtcod-headless/ with -fsanitize=address,undefined
  2. Copies the instrumented .so to __lib_debug/
  3. The existing make asan target already links against __lib_debug/ first, so it would pick up the instrumented libtcod automatically

Value

  • Catches memory bugs originating inside libtcod (FOV computation, pathfinding) that touch our grid memory
  • Enables filing memory bugs upstream to libtcod with clear ASan traces
  • Closes the last major uninstrumented gap in the grid/entity subsystem

Related

  • #258–#263 (gridstate overflow family — libtcod FOV is one trigger path)
  • #279 (memory safety audit meta-issue)
## Context The debug build system (added post-7DRL 2026) instruments McRogueFace code with ASan/UBSan, but libtcod's pre-built release binaries in `__lib/` are uninstrumented. libtcod's pathfinding and FOV operate directly on McRogueFace's grid data structures — the exact location of the #258–#263 heap overflow family. ASan can detect overflows in *our* code that corrupt *their* memory, but cannot detect bugs originating inside libtcod. Since we build libtcod from source anyway (`modules/libtcod-headless/`), adding an instrumented build is straightforward. ## Proposal Add libtcod to `tools/build_debug_python.sh` (or a companion `tools/build_debug_libs.sh`) that: 1. Builds libtcod from `modules/libtcod-headless/` with `-fsanitize=address,undefined` 2. Copies the instrumented `.so` to `__lib_debug/` 3. The existing `make asan` target already links against `__lib_debug/` first, so it would pick up the instrumented libtcod automatically ## Value - Catches memory bugs originating *inside* libtcod (FOV computation, pathfinding) that touch our grid memory - Enables filing memory bugs upstream to libtcod with clear ASan traces - Closes the last major uninstrumented gap in the grid/entity subsystem ## Related - #258–#263 (gridstate overflow family — libtcod FOV is one trigger path) - #279 (memory safety audit meta-issue)
john closed this issue 2026-04-10 08:08:46 +00:00
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Alpha Release Requirement

This issue is a blocker to 0.1 Alpha release of McRogueFace.

  
Bugfix

   
Demo Target

Functionality to demonstrate; Depends on new features, but this issue isn't for writing them.

  
Documentation

   
Major Feature

Significant time and effort required.

  
Minor Feature

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priority:tier1-active

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priority:tier2-foundation

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priority:tier3-future

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priority:tier4-deferred

   
Refactoring & Cleanup

no new functionality, just improving the codebase.

  
system:animation

Animation and property interpolation

  
system:documentation

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system:grid

Grid system and spatial containers

  
system:input

Input handling and events

  
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system:procgen

Procedural Generation (Noise, BSP, Heightmap)

  
system:python-binding

Python/C++ binding layer

  
system:rendering

Rendering pipeline and visuals

  
system:ui-hierarchy

UI component hierarchy and composition

  
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quick and easy - a few lines or with little interconnection around the codebase

  
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Blocked by other work - waiting on dependencies

  
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Needs performance testing and benchmarks

  
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Needs documentation before or after implementation

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john/McRogueFace#280
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