Thanks!

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.66%. Comparing base (a30a706) to head (7544b4a).

@@           Coverage Diff           @@
##           master     #497   +/-   ##
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  Coverage   98.66%   98.66%           
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  Files          35       35           
  Lines        5857     5857           
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  Hits         5779     5779           
  Misses         78       78           

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I went through each package to check for actual incompatibilities:

• rstan (>= 2.17.1): bayesplot only calls get_logposterior(), get_sampler_params(), summary(), and as.matrix() on stanfit objects - all stable APIs available since well before 2.17.1. No issue.
• rstanarm (>= 2.17.4): No version-specific functions are called. The stanreg S3 methods only access object properties ($stanfit, $y) and call generic summary(). No issue.
• knitr (>= 1.16): Only used for vignettes. The newest feature used is fig.asp (added in knitr 1.10), which is covered by the current minimum. No issue.
• rmarkdown (>= 1.0.0): Only used for vignettes. html_vignette and Stan code chunks work with 1.0.0. No issue.
• rstantools (>= 1.5.0): Actual incompatibility. bayesplot calls rstantools::loo_pit() and rstantools::predictive_error(), both introduced in rstantools 2.0.0. With rstantools 1.5.0 installed, requireNamespace("rstantools") would pass but the function calls would fail.