Optionally abort on any Pandoc [WARNING] (#2638) - #2640
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Pandoc prints "[WARNING] Deprecated: <arg>. ..." on stderr for deprecated command-line arguments, but such arguments only warn -- they do not fail the conversion -- so they slip past our daily nightly-Pandoc CI job unnoticed until Pandoc eventually removes the argument (e.g. --mathjax deprecated in Pandoc 3.11). When the RMARKDOWN_PANDOC_WARN_DEPRECATED environment variable is set to a truthy value, pandoc_convert() now captures Pandoc's stderr (via system2(), which handles this portably, unlike a shell "2>" redirect that broke on Windows), relays it to the user, and turns any "Deprecated:" line into an R warning. This catches deprecations generically, without enumerating the deprecated arguments one by one. The behaviour is opt-in because capturing stderr changes how Pandoc's output is relayed; the flag is enabled in the check-pandoc-daily workflow so the nightly job flags deprecated arguments in advance. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Broaden the opt-in stderr check to relay every "[WARNING] ..." line Pandoc prints (deprecated arguments, missing references, etc.) as an R warning, rather than matching only "Deprecated:". This way the nightly-Pandoc CI job fails on any Pandoc warning, not just deprecations. The environment variable is renamed RMARKDOWN_PANDOC_WARN_DEPRECATED -> RMARKDOWN_PANDOC_WARN accordingly. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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…ontext() The integration test used --citeproc to provoke a Pandoc [WARNING], but that option requires Pandoc >= 2.11 and errors out on Pandoc 2.8. Use duplicate header identifiers instead, which emit a [WARNING] on all supported Pandoc versions without failing the conversion. Also remove the testthat::context() calls, deprecated in the 3rd edition, which emitted "context() was deprecated" warnings during R CMD check. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Pandoc silently de-duplicates auto-generated header identifiers, so two
headers with the same text did not emit any [WARNING] and the expect_warning()
check failed on every Pandoc version. Give both headers the same *explicit*
identifier ({#dup}), which Pandoc reports as "Duplicate identifier" without
failing the conversion.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
When RMARKDOWN_PANDOC_ERROR_ON_WARNING is set, pandoc_convert() captures Pandoc's stderr and stop()s on any "[WARNING] ..." message. The nightly-Pandoc workflow sets it so a new deprecation or other Pandoc warning fails the job. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Follow-up to #2639, split out because it needs to be opt-in.
Motivation
Pandoc prints
[WARNING] <message>on stderr for non-fatal issues — deprecated command-line arguments (#2638), missing references, etc. These only warn, they don't fail the conversion, so they slip past our daily nightly-Pandoc CI job unnoticed (a deprecated argument, for instance, stays silent until Pandoc eventually removes it).Approach
When
RMARKDOWN_PANDOC_ERROR_ON_WARNINGis set to a truthy value,pandoc_convert()(and hencerender()) captures Pandoc's stderr, relays it, and turns any[WARNING]line into an error. This catches any Pandoc warning generically — not only deprecations, and with no per-message enumeration.Design notes:
check-pandoc-daily.yaml, so the nightly job flags Pandoc warnings in advance.