Analysis, Modeling and Testing of Darcs Patch Theory Kernel

Darcs is a distributed version control system based on a unique algebra of patches called Patch Theory. Patch Theory was originally described informally by David Roundy and the formalisation of Darcs basis continue to be an unresolved topic nowadays, which keeps open the question of Darcs reliability since it may fail in some corner cases. In this work, I follow a different approach, instead of look for a formalisation which fits Darcs implementation, I propose to capture how Darcs works and verify if it satisfies the most well-known properties of Patch Theory. Next, I analyze Darcs in two levels. First, I present an analysis of Darcs maintainability identifying some important Darcs weaknesses. Finally, I measure the coverage of an important Darcs test suite showing that there is lot of room for improvement, and I show how to improve this coverage substantially.