Reduce project slug max length from 63 to 55 characters for new projects to fix PR build errors

readthedocs/organizations/forms.py

@@ -32,7 +32,7 @@ class OrganizationForm(SimpleHistoryModelForm):
 
     # We use the organization slug + project name
     # to form the final project slug.
-    # A valid project slug is 63 chars long.
+    # A valid project slug is 55 chars long.
     name = forms.CharField(max_length=32)
 
     class Meta:

readthedocs/projects/forms.py

@@ -120,6 +120,14 @@ def clean_name(self):
                 raise forms.ValidationError(
                     _("Invalid project name"),
                 )
+            if len(potential_slug) > 55:
+                raise forms.ValidationError(
+                    _(
+                        "Project name is too long, the generated slug must be 55 characters or less. "
+                        "The current slug would be: %(slug)s"
+                    ),
+                    params={"slug": potential_slug},
+                )
 
         return name
 

readthedocs/projects/migrations/0156_reduce_slug_max_length.py

@@ -0,0 +1,65 @@
+# Generated by Django 5.2.4 on 2025-01-XX XX:XX
+from django.db import migrations
+from django.db import models
+from django.db.models.functions import Length
+from django_safemigrate import Safe
+
+
+def forwards_func(apps, schema_editor):
+    """
+    Truncate slugs and names longer than 55 characters.
+
+    PR builds use the format {project.slug}--{pr.number}, so we need to leave
+    room for the suffix. With max 6 digits for PR numbers + 2 for '--', we need
+    to reduce the max from 63 to 55 characters.
+    """
+    max_length = 55
+    Project = apps.get_model("projects", "Project")
+
+    # Truncate slugs that are too long
+    projects_invalid_slug = Project.objects.annotate(slug_length=Length("slug")).filter(
+        slug_length__gt=max_length
+    )
+    for project in projects_invalid_slug:
+        project.slug = project.slug[:max_length]
+        project.save()
+
+    # Truncate names that are too long
+    projects_invalid_name = Project.objects.annotate(name_length=Length("name")).filter(
+        name_length__gt=max_length
+    )
+    for project in projects_invalid_name:
+        project.name = project.name[:max_length]
+        project.save()
+
+
+class Migration(migrations.Migration):
+    safe = Safe.after_deploy()
+
+    dependencies = [
+        ("projects", "0155_custom_git_checkout_step"),
+    ]
+
+    operations = [
+        migrations.RunPython(forwards_func),
+        migrations.AlterField(
+            model_name="project",
+            name="slug",
+            field=models.SlugField(max_length=55, unique=True, verbose_name="Slug"),
+        ),
+        migrations.AlterField(
+            model_name="project",
+            name="name",
+            field=models.CharField(max_length=55, verbose_name="Name"),
+        ),
+        migrations.AlterField(
+            model_name="historicalproject",
+            name="slug",
+            field=models.SlugField(max_length=55, verbose_name="Slug", db_index=True),
+        ),
+        migrations.AlterField(
+            model_name="historicalproject",
+            name="name",
+            field=models.CharField(max_length=55, verbose_name="Name"),
+        ),
+    ]

readthedocs/projects/models.py

@@ -293,8 +293,9 @@ class Project(models.Model):
         related_name="projects",
     )
     # A DNS label can contain up to 63 characters.
-    name = models.CharField(_("Name"), max_length=63)
-    slug = models.SlugField(_("Slug"), max_length=63, unique=True)
+    # We limit to 55 to account for PR build suffixes (--{pr_number}).
+    name = models.CharField(_("Name"), max_length=55)
+    slug = models.SlugField(_("Slug"), max_length=55, unique=True)
     description = models.TextField(
         _("Description"),
         blank=True,

readthedocs/rtd_tests/tests/test_project_forms.py

@@ -119,6 +119,34 @@ def test_empty_slug(self):
         self.assertFalse(form.is_valid())
         self.assertIn("name", form.errors)
 
+    def test_slug_too_long(self):
+        """Test that project names that generate slugs longer than 55 chars are rejected."""
+        # Test with a name that generates a 56-character slug
+        long_name = "a" * 56
+        initial = {
+            "name": long_name,
+            "repo_type": "git",
+            "repo": "https://github.com/user/repository",
+            "language": "en",
+        }
+        form = ProjectBasicsForm(initial)
+        self.assertFalse(form.is_valid())
+        self.assertIn("name", form.errors)
+        self.assertIn("slug must be 55 characters or less", str(form.errors["name"]))
+
+    def test_slug_max_length(self):
+        """Test that project names that generate exactly 55-character slugs are accepted."""
+        # Test with a name that generates exactly 55-character slug
+        max_name = "a" * 55
+        initial = {
+            "name": max_name,
+            "repo_type": "git",
+            "repo": "https://github.com/user/repository",
+            "language": "en",
+        }
+        form = ProjectBasicsForm(initial)
+        self.assertTrue(form.is_valid())
+
     @override_settings(ALLOW_PRIVATE_REPOS=False)
     def test_length_of_tags(self):
         project = get(Project)