opencpn: fix build failure

    hash = "sha256-1JCb2aYyjaiUvtYkBFtEdlClmiMABN3a/Hts9V1sbgc=";

  };

  patches = [

    # https://github.com/OpenCPN/OpenCPN/pull/4900

    ./fix-clang20.patch

  ];

  postPatch = lib.optionalString stdenv.hostPlatform.isDarwin ''

    sed -i '/fixup_bundle/d; /NO_DEFAULT_PATH/d' CMakeLists.txt

  '';

From cb5d28c48c814454182a5169e852f2596ba018ae Mon Sep 17 00:00:00 2001

From: Ihar Hrachyshka <ihar.hrachyshka@gmail.com>

Date: Thu, 13 Nov 2025 22:25:56 -0500

Subject: [PATCH] Fix clang 20 build failure (-Wnontrivial-memcall), attempt 2

The previous attempt [1] resulted in -Werror=use-after-free violation

when built with gcc on bookworm because `*this` triggered the class

destructor, calling `free` on an uninitialized pointer.

In this new patch, we are going to use an explicit initializer list to

initialize all class members with zero values.

[1] d3eb15de1e5aa8f85890d5c83cbc025ac7a467be

---

 gui/src/IDX_entry.cpp | 52 ++++++++++++++++++++++++++++++++++++++++++-

 1 file changed, 51 insertions(+), 1 deletion(-)

diff --git a/gui/src/IDX_entry.cpp b/gui/src/IDX_entry.cpp

index 726833ccc..46923d633 100644

--- a/gui/src/IDX_entry.cpp

+++ b/gui/src/IDX_entry.cpp

@@ -29,6 +29,56 @@

 WX_DEFINE_OBJARRAY(ArrayOfIDXEntry);

-IDX_entry::IDX_entry() { memset(this, 0, sizeof(IDX_entry)); }

+IDX_entry::IDX_entry()

+    : source_data_type(SOURCE_TYPE_UNKNOWN),

+      pDataSource(nullptr),

+      IDX_rec_num(0),

+      IDX_type(0),

+      IDX_lon(0.0),

+      IDX_lat(0.0),

+      IDX_ht_time_off(0),

+      IDX_ht_mpy(0.0f),

+      IDX_ht_off(0.0f),

+      IDX_lt_time_off(0),

+      IDX_lt_mpy(0.0f),

+      IDX_lt_off(0.0f),

+      IDX_sta_num(0),

+      IDX_flood_dir(0),

+      IDX_ebb_dir(0),

+      IDX_Useable(0),

+      Valid15(0),

+      Value15(0.0f),

+      Dir15(0.0f),

+      Ret15(false),

+      IDX_tzname(nullptr),

+      IDX_ref_file_num(0),

+      IDX_ref_dbIndex(0),

+      max_amplitude(0.0),

+      have_offsets(0),

+      station_tz_offset(0),

+      IDX_time_zone(0),

+      pref_sta_data(nullptr),

+      num_nodes(0),

+      num_csts(0),

+      num_epochs(0),

+      m_cst_speeds(nullptr),

+      m_cst_nodes(nullptr),

+      m_cst_epochs(nullptr),

+      m_work_buffer(nullptr),

+      first_year(0),

+      epoch(0),

+      epoch_year(0),

+      current_depth(0),

+      b_skipTooDeep(false),

+      recent_highlow_calc_time(0),

+      recent_high_level(0.0f),

+      recent_high_time(0),

+      recent_low_level(0.0f),

+      recent_low_time(0) {

+  memset(source_ident, 0, sizeof(source_ident));

+  memset(IDX_zone, 0, sizeof(IDX_zone));

+  memset(IDX_station_name, 0, sizeof(IDX_station_name));

+  memset(IDX_reference_name, 0, sizeof(IDX_reference_name));

+}

 IDX_entry::~IDX_entry() { free(IDX_tzname); }

-- 

2.51.0