Bookdown构建报错：控制台可运行代码但提示对象/函数未找到

我正在用bookdown构建一本包含以下代码的书籍：

ggdotchart(themes, x = "theme", y = "citations",          # requires `easyGgplot2`, `ggplot2`, `ggpubr` 
            color = "#440154",                                # Color by groups
            palette = c("#00AFBB", "#E7B800", "#FC4E07"), # Custom color palette
            sorting = "descending",                       # Sort value in descending order
            add = "segments",                             # Add segments from y = 0 to dots
            rotate = TRUE,                                # Rotate vertically
            dot.size = 9,                                 # Large dot size
            label = round(themes$citations),                        # Add citations values as dot labels
            font.label = list(color = "white", size = 10, 
                              vjust = 0.5),               # Adjust label parameters
            ggtheme = theme_pubr(),                        # ggplot2 theme
            ylab="Citation Count",
            xlab="Theme"
 )

这段代码在R控制台中运行可正常生成图表，图表样式为：横向排列的主题作为x轴，y轴为引用次数，每个主题对应一个大尺寸深色圆点，圆点内带有白色引用次数数值标签，每个圆点下方有从y=0延伸的线段，整体使用pubr主题样式。

但执行knit操作时出现以下报错：

Quitting from lines 28-42 (bookdown-demo.Rmd) 
Error in ggdotchart(themes, x = "theme", y = "citations", color = "#440154",  : 
  could not find function "ggdotchart"
Calls: <Anonymous> ... withVisible -> eval_with_user_handlers -> eval -> eval
In addition: Warning message:
In xfun::prose_index(x) : Code fences are not balanced
Execution halted

执行bookdown构建操作时则出现以下报错：

Quitting from lines 54-68 (bookdown-demo.Rmd) 
Error in ggdotchart(themes, x = "theme", y = "citations", color = "#440154",  : 
  object 'themes' not found
Calls: local ... eval_with_user_handlers -> eval -> eval -> ggdotchart
Execution halted
Error: bookdown::render_book() failed to render the output format 'bookdown::gitbook'.
Execution halted

Exited with status 1.

已尝试的操作 #

• 对数据列进行类型转换：themes$citations <- as.character(themes$citations)
• 加载数据文件：load("themes.RData")

环境信息 #

• 项目基于bookdown官方演示模板的全新副本搭建

内容的提问来源于stack exchange，提问作者cmadland