+#!/usr/bin/env python
+#
+# __COPYRIGHT__
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
+
+"""
+Test for a specific race condition that used to stop a build cold when
+a Node's ref_count would get decremented past 0 and "disappear" from
+the Taskmaster's walk of the dependency graph.
+
+Note that this test does not fail every time, but would at least fail
+more than 60%-70% of the time on the system(s) I tested.
+
+The rather complicated set up here creates a condition where,
+after building four "object files" simultaneously while running with
+-j4, sets up a race condition amongst the three dependencies of the
+c6146/cpumanf.out file, where two of the dependencies are built at the
+same time (that is, by the same command) and one is built separately.
+
+We used to detect Nodes that had been started but not finished building
+and just set the waiting ref_count to the number of Nodes. In this case,
+if we got unlucky, we'd re-visit the Nodes for the two files first and
+set the ref_count to two *before* the command that built individual node
+completed and decremented the ref_count from two to one. Then when the
+two files completed, we'd update the ref_count to 1 - 2 = -1, which would
+cause the Taskmaster to *not* "wake up" the Node because it's ref_count
+hadn't actually reached 0.
+
+(The solution was to not set the ref_count, but to add to it only the
+Nodes that were, in fact, added to the waiting_parents lists of various
+child Nodes.)
+"""
+
+import TestSCons
+
+_python_ = TestSCons._python_
+
+test = TestSCons.TestSCons()
+
+test.write('build.py', """\
+import string
+import sys
+import time
+args = sys.argv[1:]
+outputs = []
+while args:
+ if args[0][0] != '-':
+ break
+ arg = args.pop(0)
+ if arg == '-o':
+ outputs.append(args.pop(0))
+ continue
+ if arg == '-s':
+ time.sleep(int(args.pop(0)))
+contents = ''
+for ifile in args:
+ contents = contents + open(ifile, 'rb').read()
+for ofile in outputs:
+ ofp = open(ofile, 'wb')
+ ofp.write('%s: building from %s\\n' % (ofile, string.join(args)))
+ ofp.write(contents)
+ ofp.close()
+""")
+
+#
+#
+#
+
+test.write('SConstruct', """\
+env = Environment()
+cmd = r'%(_python_)s build.py -o $TARGET $SOURCES'
+f1 = env.Command('c6416/cpumanf/file1.obj', 'file1.c', cmd)
+f2 = env.Command('c6416/cpumanf/file2.obj', 'file2.c', cmd)
+f3 = env.Command('c6416/cpumanf/file3.obj', 'file3.c', cmd)
+f4 = env.Command('c6416/cpumanf/file4.obj', 'file4.c', cmd)
+f5 = env.Command('c6416/cpumanf/file5.obj', 'file5.c', cmd)
+f6 = env.Command('c6416/cpumanf/file6.obj', 'file6.c', cmd)
+
+objs = f1 + f2 + f3 + f4 + f5 + f6
+
+btc = env.Command('build/target/cpumanf.out', 'c6416/cpumanf.out', cmd)
+
+addcheck_obj = env.Command('addcheck.obj', 'addcheck.c', cmd)
+
+addcheck_exe = env.Command('addcheck.exe', addcheck_obj, cmd)
+
+cmd2 = r'%(_python_)s build.py -s 2 -o ${TARGETS[0]} -o ${TARGETS[1]} $SOURCES'
+
+cksums = env.Command(['c6416/cpumanf_pre_cksum.out',
+ 'c6416/cpumanf_pre_cksum.map'],
+ objs,
+ cmd2)
+
+cpumanf_out = env.Command('c6416/cpumanf.out',
+ cksums + addcheck_exe,
+ cmd)
+
+cpumanf = env.Alias('cpumanf', objs + btc)
+
+env.Command('after.out', cpumanf, r'%(_python_)s build.py -o $TARGET after.in')
+""" % locals())
+
+test.write('file1.c', "file1.c\n")
+test.write('file2.c', "file2.c\n")
+test.write('file3.c', "file3.c\n")
+test.write('file4.c', "file4.c\n")
+test.write('file5.c', "file5.c\n")
+test.write('file6.c', "file6.c\n")
+
+test.write('addcheck.c', "addcheck.c\n")
+
+test.write('after.in', "after.in\n")
+
+test.run(arguments = '-j4 after.out')
+
+test.must_match('after.out', """\
+after.out: building from after.in
+after.in
+""")
+
+test.write('file5.c', "file5.c modified\n")
+
+test.write('after.in', "after.in modified\n")
+
+test.run(arguments = '-j4 after.out')
+
+test.must_match('after.out', """\
+after.out: building from after.in
+after.in modified
+""")
+
+test.pass_test()
projects / scons.git / commitdiff