The purpose of this demo is to get students more experience, hands-on, in a social environment, submitting pull requests to a project on Github. The content of the pull requests is not the point; instead, the idea is to focus on the social/personal concept that this is how projects often want changes submitted, and the technical side of getting practice with the tools. Students have already been through a basic tutorial on git; the idea is to cement this knowledge.
Typically, this takes the following form.
Before the session, an instructor creates a sample repository where it is safe to merge pull requests from students. This could be a personal project of theirs or a fork of someone else's project through which they create a sandbox to accept students' work where it is okay to eventually erase those changes.
The instructor begins by explaining the project in question, and showing how to find the project's Github page.
They then use the Github website to point to a particular file that can accept simple, text-based edits, typically a file like README. They then navigate to a terminal and demonstrate how to create a pull request by demonstrating all the following steps:
- They "fork" the project into their personal Github account. (In most cases, instructors are demonstrating a personal project; in this case, it would be wise for the instructor to create a dummy Github account to be the person submitting the pull request. This also avoids some trouble where Github accounts that are part of "organizations" see a slightly different fork UI than accounts that aren't.)
- They explain the key concept about forking: This copies all the history of the project into a space they are permitted to modify.
- They "clone" the repository onto their own computers.
- They make a change on their own computer, and run 'git add' on the change. Then they use 'git commit -m' to commit the change. The change is can be as simple as adding their name to a README file. It can also be silly.
- Then they 'git push' the change, which updates their master branch on Github.
- Then they visit their fork on the Github website and notice that their fork has their personal work on it.
- Then they click around in the Github UI to submit a pull request.
- Then they visit the upstream project, and show what the pull request looks like. They typically do not click "Merge" because it might create conflicts for student submissions.
- Then they tell students to submit changes, encouraging them to raise their hand if they need any help.
- The instructor sticks around at the front of the room, showing the upstream project's "List of pull requests" page, which typically automatically refreshes as students' work rolls in. Typically, seeing the student submissions makes for a lot of fun in the classroom. We often have to ask, "Hey, who is susanna112" (for example) and see a student raise their hand.
NOTE: We would do well to have a cheat sheet for students for the commands they use. Typically, students are supposed to follow along with the instructor by typing in analogous commands, with TAs roaming to help students as they run into issues. (For example, one student once ran into an issue where the Git version we recommend on Mac OS X would segfault in libcurl if using the HTTPS access method. Switching to SSH-based worked around the issue, but then she was behind.) We haved typically worked around this by having someone type the corresponding commands into IRC.
- cheat sheet v0: https://openhatch.org/wiki/Github_Demo_Steps
Also NOTE: It is important that the instructor suggest students use the HTTP(S) access method for Github; otherwise, students who do not have SSH keys set up will spend time on that, which is beside the point.
Some students may have trouble following along, and it is essential that TAs work to identify students who are not progressing well by walking around and looking at laptop screens to find students who seem stuck.