How to use github's search functionality to find code: MOM6 as an example

Presenter: @dougiesquire

Searching the MOM6 code repository in the ACCESS-NRI GitHub org. Contains all of the MOM6 Fortran code used in ACCESS-OM3

Quick summary of GitHub search functionality

Pros:

Cons:

Why use the GitHub search bar?
- See how a specific piece of code is written - how is it implemented in MOM6? Need to search through the code
Dougie’s screen: Looking at MOM6 fork on ACCESS-NRI GitHub org
- Can click on search at top or click / to start a search
- Eg search global
  - Will return all files in this repo with “Global” (not case sensitive by default)
  - Get the summary of the files, and can click to expand more lines of code
  - Can click on the line itself and it will take you to that line in the file
- Can search on multiple terms
  - Eg Global Mean - searches all files with global or mean
  - Eg “Global Mean” - search for specific phrase
  - Eg “Global mean ocean salinity” - can search directly for this diagnostic
    - Finds where it’s registered, and can backtrack to find the code
- Can search on patterns (regex) rather than words
  - Eg search Global but only at specific path: Global path:src/core
- Fast, powerful, easy to use
- Can share searches with people (can’t do this if you are, eg, using “grep” on Gadi terminal)
Gotchas
- Can only search on default branch
- GitHub doesn’t index everything, and opaque which code is indexed
  - Eg doesn’t index vendor code, but not clear what that means
  - If you search something and it seems weird that nothing is found, then this might be the main issue

Q: Can it organize the search in order of the subroutines called?
- MOM6 docs does include schematics on subroutines that are called from specific file
  - But may not be generated anymore, so may be out of date
Q: Can searches be case sensitive?
- Yes, you can use regex: /(?-i)Global/
- By default they aren’t case sensitive
Q: What is regex?
- Language for pattern matching
- Stands for regular expression
- Lots of resources online
  - Just be sure to use the correct version of regex, as there are different types
- Can click “Search syntax tips” - link at bottom of search popup in GitHub - provides quick help for lots of common regex uses
Q: OM3 configurations are all on a branch - does that mean we’ve eliminated the ability to search through OM3 configurations?
- Yes, we can’t search OM3 configurations at the moment using this tool, because there is almost nothing on the default branch. This is definitely a limitation.
- Some parameter documentation has been moved to main branch specifically to be able to search on them
- There are other ways to search through other branches, but no examples were given
- Lots of people would like GitHub to add functionality to search on a branch other than the default, but not the case currently