Close scons logfiles on completion

Files written to in logging operations could remain unclosed: more
modern Pythons grumble about this; given the type of Python build,
could emit ResourceWarning messages which cause tests to fail.
Close by registering calls with atexit.

Affects Trace, cache debug, taskmastertrace, configure.

Signed-off-by: Mats Wichmann <mats@linux.com>

5 files changed, 47 insertions, 11 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index ecf3255..88b8d6f 100755
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -150,6 +150,8 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - ParseFlags should not modify the user's passed in dict in case it's
       a compound data structure (e.g. values are lists) (issue #3665)
     - In Py3 classes no longer need to be listed as deriving from object.
+    - Close various logfiles (trace, cache, taskmastertrace, configure)
+      when done using atexit calls.
 
 
 
diff --git a/SCons/CacheDir.py b/SCons/CacheDir.py
index 5ecbc6f..3bb6671 100644
--- a/SCons/CacheDir.py
+++ b/SCons/CacheDir.py
@@ -27,13 +27,14 @@ __doc__ = """
 CacheDir support
 """
 
+import atexit
 import json
 import os
 import stat
 import sys
 
-import SCons
 import SCons.Action
+import SCons.Errors
 import SCons.Warnings
 
 cache_enabled = True
@@ -202,7 +203,11 @@ class CacheDir:
             if cache_debug == '-':
                 self.debugFP = sys.stdout
             elif cache_debug:
+                def debug_cleanup(debugFP):
+                    debugFP.close()
+
                 self.debugFP = open(cache_debug, 'w')
+                atexit.register(debug_cleanup, self.debugFP)
             else:
                 self.debugFP = None
             self.current_cache_debug = cache_debug
diff --git a/SCons/Debug.py b/SCons/Debug.py
index 706b4c4..10cd2f5 100644
--- a/SCons/Debug.py
+++ b/SCons/Debug.py
@@ -33,6 +33,7 @@ caller_trace()
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import atexit
 import os
 import sys
 import time
@@ -66,7 +67,7 @@ def string_to_classes(s):
 def fetchLoggedInstances(classes="*"):
     classnames = string_to_classes(classes)
     return [(cn, len(tracked_classes[cn])) for cn in classnames]
-  
+
 def countLoggedInstances(classes, file=sys.stdout):
     for classname in string_to_classes(classes):
         file.write("%s: %d\n" % (classname, len(tracked_classes[classname])))
@@ -201,22 +202,39 @@ if sys.platform == 'win32':
     TraceDefault = 'con'
 else:
     TraceDefault = '/dev/tty'
-
-TimeStampDefault = None
+TimeStampDefault = False
 StartTime = time.time()
 PreviousTime = StartTime
 
-def Trace(msg, file=None, mode='w', tstamp=None):
-    """Write a trace message to a file.  Whenever a file is specified,
-    it becomes the default for the next call to Trace()."""
+def Trace(msg, filename=None, mode='w', tstamp=False):
+    """Write a trace message.
+
+    Write messages when debugging which do not interfere with stdout.
+    Useful in tests, which monitor stdout and would break with
+    unexpected output. Trace messages can go to the console (which is
+    opened as a file), or to a disk file; the file argument persists
+    across calls unless overridden.
+
+    Args:
+        filename: file to write trace message to. If omitted,
+          write to the previous trace file (default: console).
+        mode: file open mode (default: 'w')
+        tstamp: write relative timestamps with trace. Outputs time since
+          scons was started, and time since last trace (default: False)
+
+    """
     global TraceDefault
     global TimeStampDefault
     global PreviousTime
+
+    def traace_cleanup(traceFP):
+        traceFP.close()
+
     if file is None:
         file = TraceDefault
     else:
         TraceDefault = file
-    if tstamp is None:
+    if not tstamp:
         tstamp = TimeStampDefault
     else:
         TimeStampDefault = tstamp
@@ -225,6 +243,7 @@ def Trace(msg, file=None, mode='w', tstamp=None):
     except KeyError:
         try:
             fp = TraceFP[file] = open(file, mode)
+            atexit.register(trace_cleanup, fp)
         except TypeError:
             # Assume we were passed an open file pointer.
             fp = file
@@ -234,7 +253,6 @@ def Trace(msg, file=None, mode='w', tstamp=None):
         PreviousTime = now
     fp.write(msg)
     fp.flush()
-    fp.close()
 
 # Local Variables:
 # tab-width:4
diff --git a/SCons/SConf.py b/SCons/SConf.py
index 42bfa8c..efa9e5b 100644
--- a/SCons/SConf.py
+++ b/SCons/SConf.py
@@ -37,6 +37,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.compat
 
+import atexit
 import io
 import os
 import re
@@ -750,11 +751,16 @@ class SConfBase:
                 _ac_config_logs[self.logfile] = None
                 log_mode = "w"
             fp = open(str(self.logfile), log_mode)
+
+            def conflog_cleanup(logf):
+                logf.close()
+
+            atexit.register(conflog_cleanup, fp)
             self.logstream = SCons.Util.Unbuffered(fp)
             # logfile may stay in a build directory, so we tell
-            # the build system not to override it with a eventually
+            # the build system not to override it with an eventually
             # existing file with the same name in the source directory
-            self.logfile.dir.add_ignore( [self.logfile] )
+            self.logfile.dir.add_ignore([self.logfile])
 
             tb = traceback.extract_stack()[-3-self.depth]
             old_fs_dir = SConfFS.getcwd()
diff --git a/SCons/Script/Main.py b/SCons/Script/Main.py
index ac29712..d7b07a2 100644
--- a/SCons/Script/Main.py
+++ b/SCons/Script/Main.py
@@ -40,6 +40,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.compat
 
+import atexit
 import importlib.util
 import os
 import re
@@ -1262,10 +1263,14 @@ def _build_targets(fs, options, targets, target_top):
             """Leave the order of dependencies alone."""
             return dependencies
 
+    def tmtrace_cleanup(tfile):
+        tfile.close()
+
     if options.taskmastertrace_file == '-':
         tmtrace = sys.stdout
     elif options.taskmastertrace_file:
         tmtrace = open(options.taskmastertrace_file, 'w')
+        atexit.register(tmtrace_cleanup, tmtrace)
     else:
         tmtrace = None
     taskmaster = SCons.Taskmaster.Taskmaster(nodes, task_class, order, tmtrace)