CS 3300 Configuration Management Cases

Case 2: Just One More Bug to Fix

The Burdell Inc. Dangerous-Acid-Plant Control System is quite small.
The team of programmers keeps its source and object code in a single
directory on single machine. Project members share the code. They know
that having lots of copies of the same code floating around is a recipe
for disaster and their single-directory strategy ensures that any
changes are immediately propagated to the others and that everyone is
working on a current version of the system.

Most of the software is integrated and working, apparently without
problem, and the program will be delivered to Dangerous-Acid-Vat Inc.
in three weeks. Bill Ultimate, crack software engineer, has just one
more bug to fix in one of the procedures for which he is responsible.
Bill edits the two source files concerned, recompiles the affected
modules, and overwrites the old files.

Questions:

1. Bill is good, but can he guarantee that his change has not
introduced a new defect?

2. Assume that Bill introduces a new defect when he attempts to fix
that last bug. When the program is executed, where is this defect
likely to manifest itself? In the procedure that Bill modified or in
some other part of the program that someone else is working on?

3. When the other members of the team suddenly find that their code has
stopped working, how will they find out what has gone wrong?