`--shift-heading-level-by=-1` turns reference section title into a non-heading

Question

`--shift-heading-level-by=-1` turns reference section title into a non-heading

Closed this issue a month ago · 2 comments

I have seen the related discussion at #9664, which refers to the behaviour that was then changed in 3d90234.

I use the latest pandoc version:

$ pandoc --version
pandoc 3.5
Features: +server +lua
Scripting engine: Lua 5.4
User data directory: /home/benjamin/.local/share/pandoc
Copyright (C) 2006-2024 John MacFarlane. Web: https://pandoc.org
This is free software; see the source for copying conditions. There is no
warranty, not even for merchantability or fitness for a particular purpose.

My problem happens when I use --citeproc with --shift-heading-level-by=-1: the section title set in metadata ends up as just a <p> instead of any heading at all.

To reproduce:

#!/usr/bin/env bash

params=(
    --from=markdown
    --to=html
    --shift-heading-level-by=-1
    --citeproc
    --standalone
)

cat << 'EOF' | pandoc "${params[@]}"
---
references:
  - id: Ritchie1974
    type: article-journal
    author:
      - family: Ritchie
        given: Dennis M.
      - family: Thompson
        given: Ken
    issued:
      - year: 1974
        month: 7
    title: The unix time-sharing system
    container-title: Commun. ACM
reference-section-title: Bibliography
---

# A post title

Some text, with [@Ritchie1974]

## A section title

Some section text.
EOF

produces

<body>
<header id="title-block-header">
<h1 class="title">A post title</h1>
</header>
<p>Some text, with <span class="citation"
data-cites="Ritchie1974">(Ritchie and Thompson 1974)</span></p>
<h1 id="a-section-title">A section title</h1>
<p>Some section text.</p>
<p>Bibliography</p>
<div id="refs" class="references csl-bib-body hanging-indent"
data-entry-spacing="0" role="list">
<div id="ref-Ritchie1974" class="csl-entry" role="listitem">
Ritchie, Dennis M., and Ken Thompson. 1974. <span>“The Unix Time-Sharing
System.”</span> <em>Commun. ACM</em>, July.
</div>
</div>
</body>

with <p>Bibliography</p>.

If I remove --shift-heading-level-by=-1, the output becomes

<body>
<h1 id="a-post-title">A post title</h1>
<p>Some text, with <span class="citation"
data-cites="Ritchie1974">(Ritchie and Thompson 1974)</span></p>
<h2 id="a-section-title">A section title</h2>
<p>Some section text.</p>
<h1 class="unnumbered" id="bibliography">Bibliography</h1>
<div id="refs" class="references csl-bib-body hanging-indent"
data-entry-spacing="0" role="list">
<div id="ref-Ritchie1974" class="csl-entry" role="listitem">
Ritchie, Dennis M., and Ken Thompson. 1974. <span>“The Unix Time-Sharing
System.”</span> <em>Commun. ACM</em>, July.
</div>
</div>
</body>

with <h1 class="unnumbered" id="bibliography">Bibliography</h1>.

I'd expect the behaviour in the first case to be a bibliography <h1> heading just like in the second case.

Complete outputs:

Buggy case

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="" xml:lang="">
<head>
  <meta charset="utf-8" />
  <meta name="generator" content="pandoc" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes" />
  <title>A post title</title>
  <style>
    html {
      color: #1a1a1a;
      background-color: #fdfdfd;
    }
    body {
      margin: 0 auto;
      max-width: 36em;
      padding-left: 50px;
      padding-right: 50px;
      padding-top: 50px;
      padding-bottom: 50px;
      hyphens: auto;
      overflow-wrap: break-word;
      text-rendering: optimizeLegibility;
      font-kerning: normal;
    }
    @media (max-width: 600px) {
      body {
        font-size: 0.9em;
        padding: 12px;
      }
      h1 {
        font-size: 1.8em;
      }
    }
    @media print {
      html {
        background-color: white;
      }
      body {
        background-color: transparent;
        color: black;
        font-size: 12pt;
      }
      p, h2, h3 {
        orphans: 3;
        widows: 3;
      }
      h2, h3, h4 {
        page-break-after: avoid;
      }
    }
    p {
      margin: 1em 0;
    }
    a {
      color: #1a1a1a;
    }
    a:visited {
      color: #1a1a1a;
    }
    img {
      max-width: 100%;
    }
    svg {
      height: auto;
      max-width: 100%;
    }
    h1, h2, h3, h4, h5, h6 {
      margin-top: 1.4em;
    }
    h5, h6 {
      font-size: 1em;
      font-style: italic;
    }
    h6 {
      font-weight: normal;
    }
    ol, ul {
      padding-left: 1.7em;
      margin-top: 1em;
    }
    li > ol, li > ul {
      margin-top: 0;
    }
    blockquote {
      margin: 1em 0 1em 1.7em;
      padding-left: 1em;
      border-left: 2px solid #e6e6e6;
      color: #606060;
    }
    code {
      font-family: Menlo, Monaco, Consolas, 'Lucida Console', monospace;
      font-size: 85%;
      margin: 0;
      hyphens: manual;
    }
    pre {
      margin: 1em 0;
      overflow: auto;
    }
    pre code {
      padding: 0;
      overflow: visible;
      overflow-wrap: normal;
    }
    .sourceCode {
     background-color: transparent;
     overflow: visible;
    }
    hr {
      background-color: #1a1a1a;
      border: none;
      height: 1px;
      margin: 1em 0;
    }
    table {
      margin: 1em 0;
      border-collapse: collapse;
      width: 100%;
      overflow-x: auto;
      display: block;
      font-variant-numeric: lining-nums tabular-nums;
    }
    table caption {
      margin-bottom: 0.75em;
    }
    tbody {
      margin-top: 0.5em;
      border-top: 1px solid #1a1a1a;
      border-bottom: 1px solid #1a1a1a;
    }
    th {
      border-top: 1px solid #1a1a1a;
      padding: 0.25em 0.5em 0.25em 0.5em;
    }
    td {
      padding: 0.125em 0.5em 0.25em 0.5em;
    }
    header {
      margin-bottom: 4em;
      text-align: center;
    }
    #TOC li {
      list-style: none;
    }
    #TOC ul {
      padding-left: 1.3em;
    }
    #TOC > ul {
      padding-left: 0;
    }
    #TOC a:not(:hover) {
      text-decoration: none;
    }
    code{white-space: pre-wrap;}
    span.smallcaps{font-variant: small-caps;}
    div.columns{display: flex; gap: min(4vw, 1.5em);}
    div.column{flex: auto; overflow-x: auto;}
    div.hanging-indent{margin-left: 1.5em; text-indent: -1.5em;}
    /* The extra [class] is a hack that increases specificity enough to
       override a similar rule in reveal.js */
    ul.task-list[class]{list-style: none;}
    ul.task-list li input[type="checkbox"] {
      font-size: inherit;
      width: 0.8em;
      margin: 0 0.8em 0.2em -1.6em;
      vertical-align: middle;
    }
    .display.math{display: block; text-align: center; margin: 0.5rem auto;}
    /* CSS for citations */
    div.csl-bib-body { }
    div.csl-entry {
      clear: both;
      margin-bottom: 0em;
    }
    .hanging-indent div.csl-entry {
      margin-left:2em;
      text-indent:-2em;
    }
    div.csl-left-margin {
      min-width:2em;
      float:left;
    }
    div.csl-right-inline {
      margin-left:2em;
      padding-left:1em;
    }
    div.csl-indent {
      margin-left: 2em;
    }  </style>
</head>
<body>
<header id="title-block-header">
<h1 class="title">A post title</h1>
</header>
<p>Some text, with <span class="citation"
data-cites="Ritchie1974">(Ritchie and Thompson 1974)</span></p>
<h1 id="a-section-title">A section title</h1>
<p>Some section text.</p>
<p>Bibliography</p>
<div id="refs" class="references csl-bib-body hanging-indent"
data-entry-spacing="0" role="list">
<div id="ref-Ritchie1974" class="csl-entry" role="listitem">
Ritchie, Dennis M., and Ken Thompson. 1974. <span>“The Unix Time-Sharing
System.”</span> <em>Commun. ACM</em>, July.
</div>
</div>
</body>
</html>

Second case

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="" xml:lang="">
<head>
  <meta charset="utf-8" />
  <meta name="generator" content="pandoc" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes" />
  <title>-</title>
  <style>
    html {
      color: #1a1a1a;
      background-color: #fdfdfd;
    }
    body {
      margin: 0 auto;
      max-width: 36em;
      padding-left: 50px;
      padding-right: 50px;
      padding-top: 50px;
      padding-bottom: 50px;
      hyphens: auto;
      overflow-wrap: break-word;
      text-rendering: optimizeLegibility;
      font-kerning: normal;
    }
    @media (max-width: 600px) {
      body {
        font-size: 0.9em;
        padding: 12px;
      }
      h1 {
        font-size: 1.8em;
      }
    }
    @media print {
      html {
        background-color: white;
      }
      body {
        background-color: transparent;
        color: black;
        font-size: 12pt;
      }
      p, h2, h3 {
        orphans: 3;
        widows: 3;
      }
      h2, h3, h4 {
        page-break-after: avoid;
      }
    }
    p {
      margin: 1em 0;
    }
    a {
      color: #1a1a1a;
    }
    a:visited {
      color: #1a1a1a;
    }
    img {
      max-width: 100%;
    }
    svg {
      height: auto;
      max-width: 100%;
    }
    h1, h2, h3, h4, h5, h6 {
      margin-top: 1.4em;
    }
    h5, h6 {
      font-size: 1em;
      font-style: italic;
    }
    h6 {
      font-weight: normal;
    }
    ol, ul {
      padding-left: 1.7em;
      margin-top: 1em;
    }
    li > ol, li > ul {
      margin-top: 0;
    }
    blockquote {
      margin: 1em 0 1em 1.7em;
      padding-left: 1em;
      border-left: 2px solid #e6e6e6;
      color: #606060;
    }
    code {
      font-family: Menlo, Monaco, Consolas, 'Lucida Console', monospace;
      font-size: 85%;
      margin: 0;
      hyphens: manual;
    }
    pre {
      margin: 1em 0;
      overflow: auto;
    }
    pre code {
      padding: 0;
      overflow: visible;
      overflow-wrap: normal;
    }
    .sourceCode {
     background-color: transparent;
     overflow: visible;
    }
    hr {
      background-color: #1a1a1a;
      border: none;
      height: 1px;
      margin: 1em 0;
    }
    table {
      margin: 1em 0;
      border-collapse: collapse;
      width: 100%;
      overflow-x: auto;
      display: block;
      font-variant-numeric: lining-nums tabular-nums;
    }
    table caption {
      margin-bottom: 0.75em;
    }
    tbody {
      margin-top: 0.5em;
      border-top: 1px solid #1a1a1a;
      border-bottom: 1px solid #1a1a1a;
    }
    th {
      border-top: 1px solid #1a1a1a;
      padding: 0.25em 0.5em 0.25em 0.5em;
    }
    td {
      padding: 0.125em 0.5em 0.25em 0.5em;
    }
    header {
      margin-bottom: 4em;
      text-align: center;
    }
    #TOC li {
      list-style: none;
    }
    #TOC ul {
      padding-left: 1.3em;
    }
    #TOC > ul {
      padding-left: 0;
    }
    #TOC a:not(:hover) {
      text-decoration: none;
    }
    code{white-space: pre-wrap;}
    span.smallcaps{font-variant: small-caps;}
    div.columns{display: flex; gap: min(4vw, 1.5em);}
    div.column{flex: auto; overflow-x: auto;}
    div.hanging-indent{margin-left: 1.5em; text-indent: -1.5em;}
    /* The extra [class] is a hack that increases specificity enough to
       override a similar rule in reveal.js */
    ul.task-list[class]{list-style: none;}
    ul.task-list li input[type="checkbox"] {
      font-size: inherit;
      width: 0.8em;
      margin: 0 0.8em 0.2em -1.6em;
      vertical-align: middle;
    }
    .display.math{display: block; text-align: center; margin: 0.5rem auto;}
    /* CSS for citations */
    div.csl-bib-body { }
    div.csl-entry {
      clear: both;
      margin-bottom: 0em;
    }
    .hanging-indent div.csl-entry {
      margin-left:2em;
      text-indent:-2em;
    }
    div.csl-left-margin {
      min-width:2em;
      float:left;
    }
    div.csl-right-inline {
      margin-left:2em;
      padding-left:1em;
    }
    div.csl-indent {
      margin-left: 2em;
    }  </style>
</head>
<body>
<h1 id="a-post-title">A post title</h1>
<p>Some text, with <span class="citation"
data-cites="Ritchie1974">(Ritchie and Thompson 1974)</span></p>
<h2 id="a-section-title">A section title</h2>
<p>Some section text.</p>
<h1 class="unnumbered" id="bibliography">Bibliography</h1>
<div id="refs" class="references csl-bib-body hanging-indent"
data-entry-spacing="0" role="list">
<div id="ref-Ritchie1974" class="csl-entry" role="listitem">
Ritchie, Dennis M., and Ken Thompson. 1974. <span>“The Unix Time-Sharing
System.”</span> <em>Commun. ACM</em>, July.
</div>
</div>
</body>
</html>

Answer 1 · 2024-11-08T17:35:37.000Z

Well, you've told pandoc to lift level-2 headings to level-1, and promote level-1 to title. If your document has a level-1 heading (and that's what pandoc will insert for reference-section-title), it won't end up as a level-1 heading. An easy workaround is to put an empty section heading (level 2!) for references at the end of your document, instead of using reference-section-title.

Perhaps we should change the behavior in one of the following ways:

Do the shift-heading-level transformation before citeproc transformations (and hence before the section heading is added in), instead of after
Change the shift-heading-level transformation so that level-1 headings after the first one are left as they are.

Answer 2 · 2024-11-08T17:57:59.000Z

Ah, that's actually a workaround I can live with very well. I was using the metadata setting to automate the heading for a pandoc wrapper I use, but I can inject a section heading instead. Happy to close this as "not really a bug".