Myron Marston myronmarston

I've discovered a crazy bug that's really confusing me. I'm curious to hear if anyone can explain it.

Here's some code in foo.rb:

class Superclass
  unless ENV['NORMAL_METHOD_DEF']
    define_method :regex do
      /^(\d)$/
    end

RSpec 3 syntax is more verbose.

About twice as many characters to type to stub something:

obj.stub(client: client)                          # old
allow(obj).to receive(:client).and_return(client) # new
allow(obj).to receive(client: client)             # possible? still much longer
allow(obj, client: client)                        # I might wrap it in this

Notes on teaching both test/unit and RSpec to new Ruby developers

@tenderlove asked "Is it good to teach RSpec (vs t/u) to people who are totally new to Ruby?" I have experience suggesting that it is a good thing; after a short back and forth, it seemed useful to write it up in detail.

Background

This goes back several years, to when I was the primary Ruby/Rails trainer for Relevance from 2006-2009. I'm guessing that worked out to probably 6-8 classes a year during those years. Since then, RSpec has changed a fair amount (with the addition of expect) and test/unit has changed radically (it has an entirely new implementation, minitest, that avoids some of the inconsistencies that made test/unit a bit confusing during the time I'm writing about here).

I started out as an RSpec skeptic. I've never been afraid of what a lot of people denigrate as "magic" in Ruby libraries … to me, if you take the trouble to understand it, that stuff's just pr

Using OTP's observer (appmon replacement) remotely

$ ssh remote-host "epmd -names"
epmd: up and running on port 4369 with data:
name some_node at port 58769

Note the running on port for epmd itself and the port of the node you're interested in debugging. Reconnect to the remote host with these ports forwarded:

$ ssh -L 4369:localhost:4369 -L 58769:localhost:58769 remote-host

	Ruby 2.1.0 in Production: known bugs and patches

	Last week, we upgraded the github.com rails app to ruby 2.1.0 in production.
	While testing the new build for rollout, we ran into a number of bugs. Most of
	these have been fixed on trunk already, but I've documented them below to help
	anyone else who might be testing ruby 2.1 in production.

	@naruse I think we should backport these patches to the ruby_2_1 branch and
	release 2.1.1 sooner rather than later, as some of the bugs are quite critical.
	I'm happy to offer any assistance I can to expedite this process.

	#!/bin/bash
	# Usage: OAUTH_TOKEN="..." backfill-releases CHANGELOG.md [<project-title>]

	set -e

	log="${1?}"
	project_name="${2}"

	repo="$(git config remote.origin.url \| grep -oE 'github\.com[/:][^/]+/[^/]+' \| sed 's/\.git$//' \| cut -d/ -f2-3)"
	[ -n "${project_name}" ] \|\| project_name="${repo#*/}"

	# install ruby-head binary from https://rubies.travis-ci.org/
	echo rvm_remote_server_url3=https://rubies.travis-ci.org > ~/.rvm/user/db
	rvm get head
	rvm reinstall ruby-head --binary

	This tool is used to compare microbenchmarks across two versions of code. It's
	paranoid about nulling out timing error, so the numbers should be meaningful.
	It runs the benchmarks many times, scaling the iterations up if the benchmark
	is extremely short, and it nulls out its own timing overhead while doing so. It
	reports results graphically with a text interface in the terminal.

	You first run it with --record, which generates a JSON dotfile with runtimes
	for each of your benchmarks. Then you change the code and run again with
	--compare, which re-runs and generates comparison plots between your recorded
	and current times. In the example output, I did a --record on the master

	module ObjectSpace
	def self.profile(&blk)
	require 'objspace'

	enable_gc = GC.disable
	ObjectSpace.trace_object_allocations(&blk)
	objs = Hash.new(0)
	ObjectSpace.each_object { \|o\|
	if (file = ObjectSpace.allocation_sourcefile(o)) && (line = ObjectSpace.allocation_sourceline(o))
	objs["#{file}:#{line}:#{o.class.name}"] += 1