warn on missing symbols by default; fixes #1794

2 files changed, 23 insertions, 25 deletions

diff --git a/src/settings.js b/src/settings.js
index 0d8d3da5..bc665973 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -390,13 +390,16 @@ var FAKE_X86_FP80 = 1; // Replaces x86_fp80 with double. This loses precision. I
 
 var GC_SUPPORT = 1; // Enables GC, see gc.h (this does not add overhead, so it is on by default)
 
-var WARN_ON_UNDEFINED_SYMBOLS = 0; // If set to 1, we will warn on any undefined symbols that
-                                   // are not resolved by the library_*.js files. We by default
-                                   // do not warn because (1) it is normal in large projects to
+var WARN_ON_UNDEFINED_SYMBOLS = 1; // If set to 1, we will warn on any undefined symbols that
+                                   // are not resolved by the library_*.js files. Note that
+                                   // it is common in large projects to
                                    // not implement everything, when you know what is not
                                    // going to actually be called (and don't want to mess with
-                                   // the existing buildsystem), and (2) functions might be
-                                   // implemented later on, say in --pre-js
+                                   // the existing buildsystem), and functions might be
+                                   // implemented later on, say in --pre-js, so you may
+                                   // want to build with -s WARN_ON_UNDEFINED_SYMBOLS=0 to
+                                   // disable the warnings if they annoy you.
+                                   // See also ERROR_ON_UNDEFINED_SYMBOLS
 
 var ERROR_ON_UNDEFINED_SYMBOLS = 0; // If set to 1, we will give a compile-time error on any
                                     // undefined symbols (see WARN_ON_UNDEFINED_SYMBOLS).
diff --git a/tests/test_other.py b/tests/test_other.py
index e54add18..ba4ed0ba 100644
--- a/tests/test_other.py
+++ b/tests/test_other.py
@@ -1455,26 +1455,21 @@ f.close()
     def clear(): try_delete('a.out.js')
 
     for args in [[], ['-O2']]:
-      clear()
-      print 'warn', args
-      output = Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'main.cpp'), '-s', 'WARN_ON_UNDEFINED_SYMBOLS=1'] + args, stderr=PIPE).communicate()
-      self.assertContained('unresolved symbol: something', output[1])
-
-      clear()
-      output = Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'main.cpp')] + args, stderr=PIPE).communicate()
-      self.assertNotContained('unresolved symbol: something\n', output[1])
-
-    for args in [[], ['-O2']]:
-      clear()
-      print 'error', args
-      output = Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'main.cpp'), '-s', 'ERROR_ON_UNDEFINED_SYMBOLS=1'] + args, stderr=PIPE).communicate()
-      self.assertContained('unresolved symbol: something', output[1])
-      assert not os.path.exists('a.out.js')
-
-      clear()
-      output = Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'main.cpp')] + args, stderr=PIPE).communicate()
-      self.assertNotContained('unresolved symbol: something\n', output[1])
-      assert os.path.exists('a.out.js')
+      for action in ['WARN', 'ERROR', None]:
+        for value in ([0, 1] if action else [0]):
+          clear()
+          print 'warn', args, action, value
+          extra = ['-s', action + '_ON_UNDEFINED_SYMBOLS=%d' % value] if action else []
+          output = Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'main.cpp')] + extra + args, stderr=PIPE).communicate()
+          if action == None or (action == 'WARN' and value):
+            self.assertContained('unresolved symbol: something', output[1])
+            assert os.path.exists('a.out.js')
+          elif action == 'ERROR' and value:
+            self.assertContained('unresolved symbol: something', output[1])
+            assert not os.path.exists('a.out.js')
+          elif action == 'WARN' and not value:
+            self.assertNotContained('unresolved symbol', output[1])
+            assert os.path.exists('a.out.js')
 
   def test_toobig(self):
     # very large [N x i8], we should not oom in the compiler