Errata backend

requirements.txt

@@ -59,6 +59,7 @@ python-magic==0.4.27
 pytz==2024.1
 requests==2.32.4
 six==1.16.0
+django-sortedm2m~=3.1
 sqlparse==0.4.4
 swapper==1.3.0
 tqdm==4.66.3

src/identifiers/logic.py

@@ -399,6 +399,12 @@ def create_crossref_journal_context(
     if journal.doi:
         journal_data["doi"] = journal.doi
         journal_data["url"] = journal.site_url()
+    if crossmark_policy_doi := setting_handler.get_setting(
+        "Identifiers",
+        "crossref_crossmark_policy_doi",
+        journal,
+    ).processed_value:
+        journal_data["crossmark_policy_doi"] = crossmark_policy_doi
 
     return journal_data
 
@@ -425,6 +431,7 @@ def create_crossref_article_context(article, identifier=None):
         "other_pages": article.page_numbers,
         "scheduled": article.scheduled_for_publication,
         "object": article,
+        "erratum_of": article.erratum_of(),
     }
 
     # append citations for i4oc compatibility

src/identifiers/tests/test_logic.py

@@ -241,6 +241,7 @@ def test_create_crossref_article_context_published(self):
             "date_accepted": None,
             "date_published": self.article_published.date_published,
             "doi": f"10.0000/TST.{self.article_published.id}",
+            "erratum_of": None,
             "id": self.article_published.id,
             "license": "",
             "object": self.article_published,
@@ -267,6 +268,7 @@ def test_create_crossref_article_context_not_published(self):
             "date_accepted": None,
             "date_published": None,
             "doi": self.doi_one.identifier,
+            "erratum_of": None,
             "id": self.article_one.id,
             "license": submission_models.Licence.objects.filter(
                 journal=self.journal_one,

src/submission/migrations/0090_genealogy.py

@@ -0,0 +1,45 @@
+# Generated by Django 4.2.29 on 2026-03-30 15:05
+
+from django.db import migrations, models
+import django.db.models.deletion
+import sortedm2m.fields
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("submission", "0089_merge_20260226_1524"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Genealogy",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                (
+                    "children",
+                    sortedm2m.fields.SortedManyToManyField(
+                        help_text=None,
+                        related_name="ancestors",
+                        to="submission.article",
+                    ),
+                ),
+                (
+                    "parent",
+                    models.OneToOneField(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="genealogy",
+                        to="submission.article",
+                        verbose_name="Introduction",
+                    ),
+                ),
+            ],
+        ),
+    ]

src/submission/models.py

@@ -64,6 +64,7 @@
 from utils.orcid import validate_orcid, COMPILED_ORCID_REGEX
 from utils.forms import plain_text_validator
 from journal import models as journal_models
+from sortedm2m.fields import SortedManyToManyField
 from review.const import (
     ReviewerDecisions as RD,
 )
@@ -2626,6 +2627,30 @@ def best_large_image_alt_text(self):
             )
         return default_text
 
+    def erratum_of(self):
+        """
+        Return the "parent" article for which this article is an erratum.
+
+        This is intended to be used in templates/common/identifiers/crossref_article.xml
+        """
+        if self.section.name != "Erratum":
+            return None
+
+        # Most articles do not have a "Genealogy"
+        if not hasattr(self, "ancestors"):
+            return None
+
+        if not self.ancestors.exists():
+            return None
+
+        # We can safely assume that an erratum refers to only one other paper
+        # so we just return the first "ancestor".
+        #
+        # Also, there is no need to check if the "parent" was published:
+        # the business logic should ensure that we cannot publish an erratum
+        # to a non-published paper.
+        return self.ancestors.first().parent
+
 
 class FrozenAuthorQueryset(model_utils.AffiliationCompatibleQueryset):
     AFFILIATION_RELATED_NAME = "frozen_author"
@@ -3396,6 +3421,28 @@ def handle_defaults(self, article):
         article.save()
 
 
+class Genealogy(models.Model):
+    """
+    Maintain relations of type parent/children between articles.
+
+    This can be used, for instance, to link erratum to the original paper.
+    """
+
+    parent = models.OneToOneField(
+        Article,
+        verbose_name=_("Introduction"),
+        on_delete=models.CASCADE,
+        related_name="genealogy",
+    )
+    children = SortedManyToManyField(
+        Article,
+        related_name="ancestors",
+    )
+
+    def __str__(self):
+        return f"Genealogy: {self.parent} has {self.children.count()} kids"
+
+
 # Signals
 
 

src/templates/common/identifiers/crossref_article.xml

@@ -54,6 +54,31 @@
                 <item_number item_number_type="article_number">{{ article.object.pk }}</item_number>
             </publisher_item>
 
+            {% if article.erratum_of %}
+            <crossmark>
+              <crossmark_policy>{{ crossmark_policy_doi }}</crossmark_policy>
+              <updates>
+                <update type="erratum" date="{{ now|date:"Y-m-d" }}">{{ article.erratum_of.get_doi }}</update>
+              </updates>
+              {% if article.object.funders.exists %}
+              <custom_metadata>
+                <fr:program name="fundref">
+                    {% for funder in article.object.funders.all %}
+                    <fr:assertion name="fundgroup">
+                        <fr:assertion name="funder_name">{{ funder.name }}</fr:assertion>
+                        {% if funder.fundref_id %}
+                        <fr:assertion name="funder_identifier">{{ funder.fundref_id }}</fr:assertion>
+                        {% endif %}
+                        {% if funder.funding_id %}
+                        <fr:assertion name="award_number">{{ funder.funding_id }}</fr:assertion>
+                        {% endif %}
+                    </fr:assertion>
+                    {% endfor %}
+                </fr:program>
+              </custom_metadata>
+              {% endif %}
+            </crossmark>
+            {% else %}
             {% if article.object.funders.exists %}
             <fr:program name="fundref">
                 {% for funder in article.object.funders.all %}
@@ -69,8 +94,7 @@
                 {% endfor %}
             </fr:program>
             {% endif %}
-
-
+            {% endif %}
 
             <doi_data>
                 <doi>{{ article.doi }}</doi>

src/utils/install/journal_defaults.json

@@ -5672,5 +5672,24 @@
             "editor",
             "journal-manager"
         ]
+    },
+    {
+        "group": {
+            "name": "Identifiers"
+        },
+        "setting": {
+            "description": "A DOI which points to a publisher's CrossMark policy document.",
+            "is_translatable": false,
+            "name": "crossref_crossmark_policy_doi",
+            "pretty_name": "Crossmark policy",
+            "type": "char"
+        },
+        "value": {
+            "default": ""
+        },
+        "editable_by": [
+            "editor",
+            "journal-manager"
+        ]
     }
 ]