aebisect [option...] [-Branch branch1]
-DELta delta1 [-Branch branch2] -DELta delta2
-- command [command_args]
The aebisect command is used to determine when in a project history some property or behavior changed. It does this by means of a bisection search through the inventory of deltas. The user must specify starting and ending deltas, which may be in historical branches of the project.
For each delta tested in the search, aebisect sets up a development directory, builds the project, and then runs the specified command in the development directory. By iteration, aebisect finds two consecutive deltas where the return code of command changed.
Note: aebisect can take considerable CPU effort, since it (normally) does a full build from scratch for each delta tested.
The following options are understood:
-HelpShow usage information.
-Project project-namespecify the project (otherwise done via the AEGIS_PROJECT environment variable)
-Change change-numberspecify the change to use for the processing (otherwise done via the AEGIS_CHANGE environment variable). The change must be in the awaiting_development state; this ensures a correct environment for building and testing.
-Branch branch-extensionspecify the branch for one of the deltas. Defaults to the baseline branch of the project. Use -b - (single dash) to specify the trunk. Branch specifiers must precede the corresponding delta specifiers.
-Logfile logfilespecify where normal output goes; defaults to $HOME/aebisect.log.
-Verboseproduce more diagnostic information (both logfile and standard output).
-Keepdo not delete working files, which are in a temporary directory. Warning: these may be voluminous!
-DIRectory pathspecify a development directory to use for building and testing.
-Minimumuse the -minimum option for the builds.
-Nobuildskip the build steps. This option is useful if the test command only involves source files. (Consider using aeannotate(1) instead.)
-Zero_onlytreat all test result codes other than 0 as equivalent.
Normally, exit status is 0 if consecutive deltas are found to bracket a change in the test command result. Exit status is 1 if errors are detected in arguments. Exit status is 2 if a subordinate command fails (possibly leaving the development directory in an uncertain state) or if the test behavior is found to be inconsistent with bisection search.
aebisect will stop on INT, QUIT, and TERM signals, probably leaving the development directory in an uncertain state.
Suppose a bug was introduced by development on project foo-4.5, sometime between version 1.2.D003 and 4.5.D006, and you have written an Aegis test script for the bug (see aent(1)), called /wrk/test/00/t0007a.sh, taking an argument for system architecture. Then the following should isolate the change which introduced the bug:
% aenc -p foo-4.5 -c 20 -file caf % aebisect -p foo-4.5 -c 20 -b 1.2 -del 3 -b 4.5 -del 6 \ -- sh /wrk/test/00/t0007a.sh linux-i486
Note that the full path for the test script is specified, since the command is executed in a development directory.
aebisect depends on aecp -delta for historical reconstructions. This can be problematic.
It is possible for a build to fail: derived files from the baseline may poison the build, or there may have been changes in the system infrastructure since the old deltas were integrated. In such cases, aebisect exits. The user may then snoop around the development directory, fix something, rebuild, perform the test, and use the logfile to see how to proceed. Remember to aedbu when done.
In some situations the problem may be cured by an additional step between aedb and aeb. A command to be interposed may be defined via the environment variable AEBISECT_DB_HOOK; this command is executed after aecp, so it may be used to patch source files see the script source for details.
Copyright © 2007 Ralph Smith
Partially derived from aeintegratq, Copyright © 1998-2005 Endocardial Solutions, Inc.
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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