Delta-flora is set of classes and functions which enable interactive analysis of Ruby code histories in an interactive Ruby shell.
The primary class is named Repository. It builds a representation of the history of all Ruby method changes in a repository. These changes are called events. You can access them in irb like this:
2.0.0p0 :001 > load 'repository.rb'
2.0.0p0 :002 > es = Repository.new('/Users/joe-shmoe/Projects/rails').eventsEach event describes the state of a method at a particular point in time. There are three types of event: added, changed, and deleted.
Regardless of type, each event contains the following information:
| field | description |
|---|---|
| type | added, changed, or deleted |
| commit | sha1 of the git commit for the code change |
| date | date of the commit |
| file_name | name of the file containing the method |
| committer | author of the commit |
| class_name | name of the class containing the method |
| method_name | name of the method (fully-qualified by class and module name) |
| start_line | start line of the method at that commit |
| end_line | end line of the method at that commit |
The file analytics.rb contains a set of functions that can be used to analyze histories. Here is function which produces a frequency histogram of the classes by the number of methods they contain:
def class_method_count_freq es
es.group_by(&:class_name)
.map {|_,v| v.map(&:method_name).uniq.count }
.freq
endLet's do that analysis:
2.0.0p0 :003 > load 'analytics.rb'
2.0.0p0 :004 > class_method_count_freq(es) => [[1, 1393], [2, 937], [3, 576], [4, 442], [5, 371], [6, 253], [7, 208], [8, 176] .. ]Events are created from the repository using the --topo-order flag on git log. This ordering puts branches one after another rather than using strict date ordering. This allows us to do simple analyses like seeing how method lengths have changed over time without the complications that we would have with strict date ordering. Although branch information is disgarded in this linear history, you can expect runs of events within branches to be date ordered.
Use of delta-flora is easy. The steps in the description should get you started. But, it's important to note that the first time you run delta-flora on a repo it takes considerable amount of time rip the repo and produce method events.
To make use easier, the Repository class has been designed to check for a file named methodevents.csv in the repository directory. If it exists and there are no commits with a later datestamp in the repo, then methodevents.csv is assumed to be current and it is loaded. If methodevents.csv does not exist or it is out of date, Repository rips the repo and produces a methodevents.csv file.
The phrase es = Repository.new('some repostory path').events is a bit verbose, so delta-flora supplies a convenience method that has the same effect:
es = load_events('some repository path')Delta Flora is the name of an album by Hughscore: a group formed by the late Hugh Hopper of Soft Machine. I chose the name because its literal meaning is the flowering/bountiful mouth of a river. It seemed like a good name for a tool that produces useful information from repositories. Aside from that, the pun on the word delta with regard to version control systems was too good to pass up.
- Ruby 2.6 or greater
(The MIT License)
Copyright(c) 2015-2020 Michael Feathers
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