Format of error message is wrong

[joelnitta]

In Episode 6, Best Practices for targets Project Organization the error message that is output (intentionally, for demonstration purposes during the lesson) by targets stretches across multiple code chunks.

The relevant code is here:

targets-workshop/episodes/organization.Rmd

Lines 135 to 143 in 80dc178

	```{r}
	#| echo: FALSE
	#| label: example-bad-pipeline-hide
	#| error: true
	tar_dir({
	write_example_plan(chunk = "example-bad-pipeline-show")
	tar_make()
	})
	```

[joelnitta]

The actual error in R looks like this:

Error:
! targets::tar_make() error

── General debugging ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
    • tar_errored()
    • tar_meta(fields = any_of("error"), complete_only = TRUE)
    • tar_workspace()
    • tar_workspaces()

── How to ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
    • Debug: https://books.ropensci.org/targets/debugging.html
    • Help: https://books.ropensci.org/targets/help.html

── Last error message ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
    duplicated target names: height

── Last error traceback ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
    base::tryCatch(base::withCallingHandlers({ NULL base::saveRDS(base::do.c...
    tryCatchList(expr, classes, parentenv, handlers)
    tryCatchOne(tryCatchList(expr, names[-nh], parentenv, handlers[-nh]), na...
    doTryCatch(return(expr), name, parentenv, handler)
    tryCatchList(expr, names[-nh], parentenv, handlers[-nh])
    tryCatchOne(expr, names, parentenv, handlers[[1L]])
    doTryCatch(return(expr), name, parentenv, handler)
    base::withCallingHandlers({ NULL base::saveRDS(base::do.call(base::do.ca...
    base::saveRDS(base::do.call(base::do.call, base::c(base::readRDS("/var/f...
    base::do.call(base::do.call, base::c(base::readRDS("/var/folders/gp/h665...
    (function (what, args, quote = FALSE, envir = parent.frame()) { if (!is....
    (function (targets_function, targets_arguments, options, envir = NULL, s...
    tryCatch(out <- withCallingHandlers(targets::tar_callr_inner_try(targets...
    tryCatchList(expr, classes, parentenv, handlers)
    tryCatchOne(expr, names, parentenv, handlers[[1L]])
    doTryCatch(return(expr), name, parentenv, handler)
    withCallingHandlers(targets::tar_callr_inner_try(targets_function = targ...
    targets::tar_callr_inner_try(targets_function = targets_function, target...
    pipeline_from_list(targets)
    pipeline_from_list.default(targets)
    pipeline_init(out)
    pipeline_targets_init(targets, clone_targets)
    tar_assert_unique_targets(names)
    tar_throw_validate(message)
    tar_error(message = paste0(...), class = c("tar_condition_validate", "ta...
    rlang::abort(message = message, class = class, call = tar_empty_envir)
    signal_abort(cnd, .file)

[tobyhodges]

Running knitr::knit('organization.Rmd') gives me an organization.md output that includes this:

[ ...snip... ]

You would get an error if you tried to run the equivalent targets pipeline:


``` r
tar_plan(
    height = 160,
    height = height / 2.54
)
```


```
## 
-

\

|

 
```

```
## 
```

```
## ── Debugging ─────────────────────────────────────────────────────────────────────────────────────────────────────
```

```
## 
```

```
## ── How to ────────────────────────────────────────────────────────────────────────────────────────────────────────
```

```
## 
```

```
## ── Last error message ────────────────────────────────────────────────────────────────────────────────────────────
```

```
## 
```

```
## ── Last error traceback ──────────────────────────────────────────────────────────────────────────────────────────
```

```
## Error:
## ! targets::tar_make() error
##     • tar_errored()
##     • tar_meta(fields = any_of("error"), complete_only = TRUE)
##     • tar_workspace()
##     • tar_workspaces()
##     • Debug: �]8;;https://books.ropensci.org/targets/debugging.html�https://books.ropensci.org/targets/debugging.html�]8;;�
##     • Help: �]8;;https://books.ropensci.org/targets/help.html�https://books.ropensci.org/targets/help.html�]8;;�
##     duplicated target names: height
##     base::tryCatch(base::withCallingHandlers({ NULL base::saveRDS(base::do.c...
##     tryCatchList(expr, classes, parentenv, handlers)
##     tryCatchOne(tryCatchList(expr, names[-nh], parentenv, handlers[-nh]), na...
##     doTryCatch(return(expr), name, parentenv, handler)
##     tryCatchList(expr, names[-nh], parentenv, handlers[-nh])
##     tryCatchOne(expr, names, parentenv, handlers[[1L]])
##     doTryCatch(return(expr), name, parentenv, handler)
##     base::withCallingHandlers({ NULL base::saveRDS(base::do.call(base::do.ca...
##     base::saveRDS(base::do.call(base::do.call, base::c(base::readRDS("/var/f...
##     base::do.call(base::do.call, base::c(base::readRDS("/var/folders/rj/3gf6...
##     (function (what, args, quote = FALSE, envir = parent.frame()) { if (!is....
##     (function (targets_function, targets_arguments, options, envir = NULL, s...
##     tryCatch(out <- withCallingHandlers(targets::tar_callr_inner_try(targets...
##     tryCatchList(expr, classes, parentenv, handlers)
##     tryCatchOne(expr, names, parentenv, handlers[[1L]])
##     doTryCatch(return(expr), name, parentenv, handler)
##     withCallingHandlers(targets::tar_callr_inner_try(targets_function = targ...
##     targets::tar_callr_inner_try(targets_function = targets_function, target...
##     pipeline_from_list(targets)
##     pipeline_from_list.default(targets)
##     pipeline_init(out)
##     pipeline_targets_init(targets, clone_targets)
##     tar_assert_unique_targets(names)
##     tar_throw_validate(message)
##     tar_error(message = paste0(...), class = c("tar_condition_validate", "ta...
##     rlang::abort(message = message, class = class, call = tar_envir_base)
##     signal_abort(cnd, .file)
```

[... snip ...]

I may be wrong, but my interpretation of this is that the issue is not specific to sandpaper exactly: there is something that knitr does not like about the output of that code chunk, which causes incorrect Markdown to be built from the R Markdown...

Fair to say that I do not have a complete understanding of targets, knitr, or sandpaper but, if I had to place a bet, I predict that the problem stems from the links in the error message (note the character encoding errors next to "Debug" and "Help" in the output...)