[geos-devel] 3.8.0 problems building on Windows

[Asa Packer]

Hi,

I just started working with version 3.8.0, trying to build it on Windows.  I ran into two issues:


  1.  Out of the box I can't build geos 3.8.0 with a fully-updated Visual Studio 2017, because geos wants cmake 3.13 and VS2017 only has 3.12.  If I change line 22 of the top-level CMakeLists.txt to require only 3.12, then I can build fine in Release mode, either 32 or 64 bit, and ctest shows no failures.
  2.  If I build in Debug mode, with either VS2017 or VS2019, I get tons of assertion failures when I do ctest.  They all come from line 115 of MonotoneChainBuilder.cpp, which on the last time through the loop causes an access of an element one past the end of a std::vector.  Even if I ignore the assertion failures, the tests show as fails because the C runtime considers these to be fatal errors.

Below is a patch that fixes these issues.  Are these reasonable workarounds?

Thanks!

Asa

Index: geos-3.8.0/CMakeLists.txt
===================================================================
--- geos-3.8.0/CMakeLists.txt
+++ geos-3.8.0/CMakeLists.tt
@@ -19,7 +19,7 @@
# Require CMake 3.13+ with VS generator for complete support of VS versions
# and support by AppVeyor.
if(${CMAKE_GENERATOR} MATCHES "Visual Studio")
-  cmake_minimum_required(VERSION 3.13 FATAL_ERROR)
+  cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
endif()
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
Index: geos-3.8.0/src/index/chain/MonotoneChainBuilder.cpp
===================================================================
--- geos-3.8.0/src/index/chain/MonotoneChainBuilder.cpp
+++ geos-3.8.0/src/index/chain/MonotoneChainBuilder.cpp
@@ -111,8 +111,10 @@
             }
         }
         ++last;
-        prev = curr;
-        curr = &pts[last];
+        if (last < npts) {
+            prev = curr;
+            curr = &pts[last];
+        }
     }
#if GEOS_DEBUG
     std::cerr << "MonotoneChainBuilder::findChainEnd() returning" << std::endl;


Asa Packer  | Lead Systems Engineer

BioSonics, Inc.
2356 W Commodore Way, Unit 110
Seattle WA 98199-1258 USA
tel 206.782.2211 |  biosonicsinc.com<http://www.biosonicsinc.com/>

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