With Mercurial and Progress

  Introduction  What is version control ?  Why use version control ?  Centralised vs. Distributed  Why Mercurial ?  Using Mercurial [with Progress]  Examples / Demos  Questions Overview

  Julian Lyndon-Smith, dot.r limited  Progress developer since v3  Fan of vcs since 1987  Developed, sold Boss (Progress-based vcs)  Other vcs systems used include  Roundtable ~  SourceSafe ~  Cvs ~  Subversion ~ Introduction

  As developers, we write code that changes over time  Bugs  aka “feature”  aka “undocumented behaviour”  aka “works on my machine”  New functionality  Aka “we could charge for this”  Better way of doing something  aka “I want to play with this cool new tech” What is version control?

  Everyone uses a version control system  Just not the right one  Copy foo.p foo.[x].p (where x=1 to … )  Modify foo.p What is version control?

  Audit trail of changes  Who did what, where, why and when ?  Syncronization  Share the same code between developers  Backup  Get any version of the file from any time  Revert  Throw away local changes Why use version control?

 Centralised vcs checkout checkin checkout checkin checkout

 Centralised vcs  Centralized version control systems  Cvs  Source safe  Rcs  Subversion  Single central copy of project / source (aka “repo”)  Committing records changes into central repo  Other developers see this change

 Centralised vcs  Workflow  Pull changes from central repo  Make changes  Commit changes back to central repo  Disadvantages  Only “latest” copy of source available  Need to be online / connected  All changes to a file have to be in one changeset

 Strengths  Workflow is familiar to most developers  Only one place for all source  Trunk has latest version

 Weaknesses  Poor merging  No offline commits  Any commit is available to all users  Working or not  Breaks build servers  Days or weeks between checkins  Commits only apply to selected subdirectory and children (subversion)

 Distributed vcs checkout checkin checkout checkin checkout checkin checkout QA RepoBuild Repo

 Distributed vcs  Distributed version control systems  Mercurial  Git  Arcs  Bazaar  Multiple copies of all versions of project / source  Committing records changes into local repo  Other developers do not see this change  Until pushed back to remote repo

 Distributed vcs  Workflow  Clone repo  Make changes  Commit changes back to own repo  Push changes up to remote repo  Disadvantages  None …

 Strengths  All repositories are equal  Offline history  Offline commit  Less chance of merge conflicts  “hidden” experimental branches

 Weaknesses  Who has the “latest” version ?  Large Binary files  Fixed in later releases  Mindset

 Why mercurial ?  Boiled down to git or mercurial  Git  Poor documentation  Complicated command lines  Gui for eclipse did not work for me  Mercurial  Worked first time  Gui worked first time  Purely personal choice.

 Using mercurial  The basics

 Using mercurial  Download from  Update settings

 Using mercurial  Download from  Go to your source code directory  hg init  There’s now a.hg directory  Now “add” the source files to the repository  hg add  Now commit the files to the repository  hg commit

 Using mercurial  So, what happened in the repository ?  hg log  Shows the history of changes  User, notes, changeset id and date  In reverse order (latest first)  Let’s make a change to a file ( h-BinCheck.p )  And commit it  hg commit

 Using mercurial  Let’s see the log now  hg log  What were the changes ?  hg diff –r0:1 h-BinCheck.p  Let’s make more changes  What is the status of my working directory ?  hg status  What were the changes ?  hg diff

 Using mercurial  Don’t like what you see ?  hg revert (creates.orig file)  hg revert –no-backup (no.orig file)

 Mercurial Repositories checkout checkin checkout checkin checkout checkin checkout QA RepoBuild Repo

 Mercurial Repositories  A “Central” repository is useful for  Providing a master repo for QA  Providing a convenient repo for cloning  Hg serve  Starts a webserver on port 8000  Allows a repo to be accessed by other developers  Server or developer machine  Generally LAN only

 Mercurial Repositories  Bitbucket   Free for up to 5 users  Built-in issue tracking  Unlimited repositories (private / public)  Available wherever there is an internet connection  Demo: Create a new repository (pugus)

  Creates a repository from another repository  hg clone pugushttps://bitbucket.org/jmls/pugus  Inits the repo  Downloads the entire repository  Updates the working directory  Add a new file, commit  hg add  hg commit Cloning

 Repository changesets n/a [empty repository] bitbucket 0 My initial version my computer

 Pushing changes  Now we need to push changes up to remote repo  hg push  Rinse, repeat  make another change “added comments”  commit, push 0 My initial version bitbucket 0 My initial version my computer

 Pushing changes  Now we have  hg push 1 Added comments 0 My initial version bitbucket 1 Added comments 0 My initial version my computer

 Another developer..  Alice has been added to the dev team  Needs to clone the repository  hg clone 1 Added comments 0 My initial version bitbucket 1 Added comments 0 My initial version Alice 1 Added comments 0 My initial version my computer

 Multiple changes  I add a new file  Alice modifies readme.txt  Both commit 2 Added install.txt 1 Added comments 0 My initial version my computer 2 Added copyright message 1 Added comments 0 My initial version Alice

 Alice pushes  Alice pushes to remote repo 2 Added copyright message 1 Added comments 0 My initial version bitbucket 2 Added copyright message 1 Added comments 0 My initial version Alice

 I push  I push to remote repo  Fails.  I need to get the updated changesets before I can push  hg incoming  Shows all changes  hg pull  Now there are 2 heads (mine and Alice’s)  Working directory not updated

 I push  Merge the two heads  hg merge  Updates working directory  hg commit  hg push

  Alice doesn’t have the latest version I push 4 merged changesets 3 Added install.txt 2 Added copyright message 1 Added comments 0 My initial version bitbucket 4 Merged changesets 3 Added copyright message 2 Added install.txt 1 Added comments 0 My initial version my computer 2 Added copyright message 1 Added comments 0 My initial version Alice

  Alice doesn’t have the latest version  hg pull  No merge needed, just update  hg update  Alice now has the latest version of the repository Alice pulls 4 Merged changesets 3 Added install.txt 2 Added copyright message 1 Added comments 0 My initial version alice

 General workflow pullupdate Make changes commitPullMergeTestCommitpush

 Workbench demo

  Help => Install new Software Mercurial Eclipse

  Create new Progress project  File => New=>Other Mercurial Eclipse

  To create a Progress view on the project  Select Project Properties  Select Project Facets  Select Openedge / GUI for.net  Apply  Now we have a progress project with a mercurial team  No more command line ;) Mercurial Eclipse