---
title: "FAQ"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{FAQ}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
```

## Authentication

#### Q-Auth-1

I am getting an error when using `circle::use_circle_deploy()` or `tic::use_ghactions_deploy()`.

**Answer**

In most cases this is related to API authentication issues.
Ensure that the following points are met:

1. For Circle CI, install the respective GitHub App from the [GitHub Marketplace](https://github.com/marketplace).
2. Ensure that you have set the respective API keys for the problematic provider in your `.Renviron` file.
  Consult the help pages of the respective `use_*_deploy()` function for more help.
  - GitHub Actions: A `GITHUB_PAT` with "public_repo" scopes.
  - Circle CI: Env var `R_CIRCLE`.

## GitHub Actions

#### Q-GHA-1

How is {tic} different from what [r-lib/actions](https://github.com/r-lib/actions) does?

**Answer**

{tic} uses [r-lib/actions](https://github.com/r-lib/actions) as the base to install R in the first place.
However in detail, {tic} does the following things differently which aim to enhance the CI experience:

- Caching: {tic} caches the whole R library rather than only the direct dependencies of a package.
  This has the advantage that packages required for side actions ({pkgdown} deployment, README updates) will also be cached.

- `ccache`: {tic} comes with a compiler cache for source installations of packages by default, speeding up repeated source installation highly.
  The compiler cache directory (`.ccache`) will also be cached (once a week).
  Example use case: If you installed {Rcpp} from source as a dependency of your package and have it stored in your cache and {Rcpp} now updates two days later, the reinstallation will make use of the compiler cache and install {Rcpp} instantly rather than recompiling the C code again.

- Number of CPUs: {tic} uses 4 CPUs by default instead of only 1 as [r-lib/actions](https://github.com/r-lib/actions) does.
  This speeds up package installation a lot.
  4 CPUs are max because all GitHub Actions runners have 2 hyperthreading cores available.

- Use of SSH deployment keys: Once set up via `tic::use_ghactions_deploy()`, this deployment approach makes it possible to push any file of your repository to any branch of your remote.
  Other deployment approaches often limit you to only push to `gh-pages` branch or similar.

## Other

#### Q-Other-1

Is it possible to update the CI YAML templates installed by {tic} with upstream changes?

**Answer**

Yes! Have a look at ["Updating Templates"](https://docs.ropensci.org/tic/articles/updating.html) for more information.

---

#### Q-Other-2

Am I the only one using {tic}?

**Answer**

You can see who and how many people use {tic.R} on GitHub via this query: https://github.com/search?p=5&q=filename%3Atic.R&type=Code

---

#### Q-Other-3

Package {rgl} fails to install because of either

- "configure: error: X11 not found but required, configure aborted."
- "error: X11 not found; XQuartz (from www.xquartz.org) is required to run rgl."

**Answer**

The first one is usually caused by a missing installation of `XQuartz` on macOS.
Add `brew install xquartz` to the runner.

The second error requires to set the `DISPLAY` env var to mimic a non-headless state.
Add `export DISPLAY=:99` to the stage in which {rgl} should be installed.
If the warning message during loading of {rgl} should be suppressed, either env var `RGL_USE_NULL = TRUE` can be set or R option `options(rgl.useNull = TRUE)`.