Warnings can be disabled

7 files changed, 59 insertions, 7 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 1f68bd71..e5de64e1 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -9,6 +9,11 @@ Change history for Coverage.py
 Unreleased
 ----------
 
+- Some warnings can now be individually disabled.  Warnings that can be
+  disabled have a short name appended.  The ``[run] disable_warnings`` setting
+  takes a list of these warning names to disable. Closes both `issue 96`_ and
+  `issue 355`_.
+
 - In previous versions, calling a method that used collected data would prevent
   further collection.  For example, `save()`, `report()`, `html_report()`, and
   others would all stop collection.  An explicit `start()` was needed to get it
@@ -28,6 +33,8 @@ Unreleased
   kitted versions of coverage.py.  Now it is.
 
 .. _issue 79: https://bitbucket.org/ned/coveragepy/issues/79/save-prevents-harvesting-on-stop
+.. _issue 96: https://bitbucket.org/ned/coveragepy/issues/96/unhelpful-warnings-produced-when-using
+.. _issue 355: https://bitbucket.org/ned/coveragepy/issues/355/warnings-should-be-suppressable
 .. _issue 448: https://bitbucket.org/ned/coveragepy/issues/448/save-and-html_report-prevent-further
 
 
diff --git a/coverage/config.py b/coverage/config.py
index 3dd6ea9c..3651de33 100644
--- a/coverage/config.py
+++ b/coverage/config.py
@@ -158,6 +158,7 @@ class CoverageConfig(object):
         self.cover_pylib = False
         self.data_file = ".coverage"
         self.debug = []
+        self.disable_warnings = []
         self.note = None
         self.parallel = False
         self.plugins = []
@@ -191,7 +192,7 @@ class CoverageConfig(object):
         # Options for plugins
         self.plugin_options = {}
 
-    MUST_BE_LIST = ["omit", "include", "debug", "plugins", "concurrency"]
+    MUST_BE_LIST = ["concurrency", "debug", "disable_warnings", "include", "omit", "plugins"]
 
     def from_args(self, **kwargs):
         """Read config values from `kwargs`."""
@@ -283,6 +284,7 @@ class CoverageConfig(object):
         ('cover_pylib', 'run:cover_pylib', 'boolean'),
         ('data_file', 'run:data_file'),
         ('debug', 'run:debug', 'list'),
+        ('disable_warnings', 'run:disable_warnings', 'list'),
         ('include', 'run:include', 'list'),
         ('note', 'run:note'),
         ('omit', 'run:omit', 'list'),
diff --git a/coverage/control.py b/coverage/control.py
index b67ed904..aeca9f71 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -608,6 +608,10 @@ class Coverage(object):
 
         For warning suppression, use `slug` as the shorthand.
         """
+        if slug in self.config.disable_warnings:
+            # Don't issue the warning
+            return
+
         self._warnings.append(msg)
         if slug:
             msg = "%s (%s)" % (msg, slug)
diff --git a/doc/cmd.rst b/doc/cmd.rst
index acc56d52..e9d5100b 100644
--- a/doc/cmd.rst
+++ b/doc/cmd.rst
@@ -131,40 +131,53 @@ If you are measuring coverage in a multi-process program, or across a number of
 machines, you'll want the ``--parallel-mode`` switch to keep the data separate
 during measurement.  See :ref:`cmd_combining` below.
 
+
+.. _cmd_warnings:
+
+Warnings
+--------
+
 During execution, coverage.py may warn you about conditions it detects that
 could affect the measurement process.  The possible warnings include:
 
-* "Trace function changed, measurement is likely wrong: XXX"
+* "Trace function changed, measurement is likely wrong: XXX (trace-changed)"
 
   Coverage measurement depends on a Python setting called the trace function.
   Other Python code in your product might change that function, which will
-  disrupt coverage.py's measurement.  This warning indicate that has happened.
+  disrupt coverage.py's measurement.  This warning indicates that has happened.
   The XXX in the message is the new trace function value, which might provide
   a clue to the cause.
 
-* "Module XXX has no Python source"
+* "Module XXX has no Python source (module-not-python)"
 
   You asked coverage.py to measure module XXX, but once it was imported, it
   turned out not to have a corresponding .py file.  Without a .py file,
   coverage.py can't report on missing lines.
 
-* "Module XXX was never imported"
+* "Module XXX was never imported (module-not-imported)"
 
   You asked coverage.py to measure module XXX, but it was never imported by
   your program.
 
-* "No data was collected"
+* "No data was collected (no-data-collected)"
 
   Coverage.py ran your program, but didn't measure any lines as executed.
   This could be because you asked to measure only modules that never ran,
   or for other reasons.
 
-* "Module XXX was previously imported, but not measured."
+* "Module XXX was previously imported, but not measured. (module-not-measured)"
 
   You asked coverage.py to measure module XXX, but it had already been imported
   when coverage started.  This meant coverage.py couldn't monitor its
   execution.
 
+Individual warnings can be disabled with the `disable_warnings
+<config_run_disable_warnings>`_ configuration setting.  To silence "No data was
+collected," add this to your .coveragerc file::
+
+    [run]
+    disable_warnings = no-data-collected
+
 
 .. _cmd_datafile:
 
diff --git a/doc/config.rst b/doc/config.rst
index 89493ece..0740ef1e 100644
--- a/doc/config.rst
+++ b/doc/config.rst
@@ -126,6 +126,12 @@ Before version 4.2, this option only accepted a single string.
 for storing or reporting coverage. This value can include a path to another
 directory.
 
+.. _config_run_disable_warnings:
+
+``disable_warnings`` (multi-string): a list of warnings to disable.  Warnings
+that can be disabled include a short string at the end, the name of the
+warning. See :ref:`cmd_warnings` for specific warnings.
+
 ``debug`` (multi-string): a list of debug options.  See :ref:`the run
 --debug option <cmd_run_debug>` for details.
 
diff --git a/tests/test_config.py b/tests/test_config.py
index 2aa592b9..9224046a 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -245,6 +245,7 @@ class ConfigFileTest(CoverageTest):
             plugins.a_plugin
             plugins.another
         debug = callers, pids  ,     dataio
+        disable_warnings =     abcd  ,  efgh
 
         [{section}report]
         ; these settings affect reporting.
@@ -325,6 +326,7 @@ class ConfigFileTest(CoverageTest):
         self.assertTrue(cov.config.parallel)
         self.assertEqual(cov.config.concurrency, ["thread"])
         self.assertEqual(cov.config.source, ["myapp"])
+        self.assertEqual(cov.config.disable_warnings, ["abcd", "efgh"])
 
         self.assertEqual(cov.get_exclude_list(), ["if 0:", r"pragma:?\s+no cover", "another_tab"])
         self.assertTrue(cov.config.ignore_errors)
diff --git a/tests/test_process.py b/tests/test_process.py
index 237bc3c7..16341f5d 100644
--- a/tests/test_process.py
+++ b/tests/test_process.py
@@ -499,6 +499,24 @@ class ProcessTest(CoverageTest):
             Coverage.py warning: No data was collected. (no-data-collected)
             """), out)
 
+    def test_warnings_suppressed(self):
+        self.make_file("hello.py", """\
+            import sys, os
+            print("Hello")
+            """)
+        self.make_file(".coveragerc", """\
+            [run]
+            disable_warnings = no-data-collected, module-not-imported
+            """)
+        out = self.run_command("coverage run --source=sys,xyzzy,quux hello.py")
+
+        self.assertIn("Hello\n", out)
+        self.assertIn(textwrap.dedent("""\
+            Coverage.py warning: Module sys has no Python source. (module-not-python)
+            """), out)
+        self.assertNotIn("module-not-imported", out)
+        self.assertNotIn("no-data-collected", out)
+
     def test_warnings_during_reporting(self):
         # While fixing issue #224, the warnings were being printed far too
         # often.  Make sure they're not any more.