getS16NoEx() returns true unless syntactical error in conf. (#8304)

The getS16NoEx() handler will return true unless there is a
`[num_emerge_threads]` line in the `minetest.conf` at which
point the excption handler part is reached. Due to the fact that
`defaultsettings.cpp` has a default value set for this setting,
that never will happen.

Because of this, the code will never check the number of threads on
the system, and keep `nthreads = 0`. If that happens, the value is
changed to `1` and only 1 emerge thread will be used.

The default should be set to `1` instead, due to the potential unsafe
consequences for the standard sqlite map files, but that should be a
separate commit that also adds documentation for that setting. This
commit focuses on removing this `hiding` bug instead.

diff --git a/src/emerge.cpp b/src/emerge.cpp
index 592b1bef7c838200eb390cf7c7727bf07d7f7de3..0ad6ee29b9d7d57ff202ef5d07c2ceb1d7d902e9 100644 (file)
--- a/src/emerge.cpp
+++ b/src/emerge.cpp
@@ -130,11 +130,13 @@ EmergeManager::EmergeManager(Server *server)
 
        // If unspecified, leave a proc for the main thread and one for
        // some other misc thread
-       s16 nthreads = 0;
-       if (!g_settings->getS16NoEx("num_emerge_threads", nthreads))
+       s16 nthreads;
+       g_settings->getS16NoEx("num_emerge_threads", nthreads);
+       if (nthreads == 0)
                nthreads = Thread::getNumberOfProcessors() - 2;
        if (nthreads < 1)
                nthreads = 1;
+       verbosestream << "Using " << nthreads << " emerge threads." << std::endl;
 
        m_qlimit_total = g_settings->getU16("emergequeue_limit_total");
        if (!g_settings->getU16NoEx("emergequeue_limit_diskonly", m_qlimit_diskonly))