[R-package] [docs] remove devtools dependency for docs builds (fixes #3036)

R-package/pkgdown/_pkgdown.yml

@@ -6,6 +6,13 @@ site:
   root: ''
   title: LightGBM, Light Gradient Boosting Machine
 
+repo:
+  url:
+    home: https://github.com/microsoft/LightGBM/
+    source: https://github.com/microsoft/LightGBM/tree/master/R-package/
+    issue: https://github.com/microsoft/LightGBM/issues/
+    user: https://github.com/
+
 development:
   mode: unreleased
 

build_r_site.R

@@ -1,17 +1,18 @@
 library(pkgdown)
+library(roxygen2)
 
 setwd("lightgbm_r")
 if (!dir.exists("docs")) {
   dir.create("docs")
 }
 
-devtools::document()
-clean_site()
-init_site()
-build_home(preview = FALSE, quiet = FALSE)
-build_reference(
+roxygen2::roxygenize(load = "installed")
+pkgdown::clean_site()
+pkgdown::init_site()
+pkgdown::build_home(preview = FALSE, quiet = FALSE)
+pkgdown::build_reference(
     lazy = FALSE
-    , document = FALSE
+    , devel = FALSE
     , examples = TRUE
     , run_dont_run = FALSE
     , seed = 42L

docs/conf.py

@@ -227,20 +227,18 @@ def generate_r_docs(app):
     echo 'options(repos = "https://cran.rstudio.com")' > $HOME/.Rprofile
     /home/docs/.conda/bin/conda create -q -y -n r_env \
         r-base=3.5.1=h1e0a451_2 \
-        r-devtools=1.13.6=r351h6115d3f_0 \
         r-jsonlite=1.5=r351h96ca727_0 \
         r-matrix=1.2_14=r351h96ca727_0 \
         r-testthat=2.0.0=r351h29659fb_0 \
-        cmake=3.14.0=h52cb24c_0 \
-        ca-certificates=2019.11.27=0
+        cmake=3.14.0=h52cb24c_0
     /home/docs/.conda/bin/conda install -q -y -n r_env -c conda-forge \
         r-data.table=1.12.8=r35hcdcec82_0 \
-        r-pkgdown=1.3.0=r35h6115d3f_1001 \
-        r-roxygen2=6.1.1=r35h0357c0b_1001
+        r-pkgdown=1.5.1=r35h6115d3f_0 \
+        r-roxygen2=7.1.0=r35h0357c0b_0
     source /home/docs/.conda/bin/activate r_env
     export TAR=/bin/tar
     cd {0}
-    sed -i'.bak' '/# Build the package (do not touch this line!)/q' build_r.R
+    export R_LIBS="/home/docs/.conda/envs/r_env/lib/R/library"
     Rscript build_r.R
     Rscript build_r_site.R
     """.format(os.path.join(CURR_PATH, os.path.pardir))