We noticed that the scraper is picking up many Cite errors which don't seem to be rendered.

Questions:

• Is this a problem with the HTML dump parser configuration
  • No, Parsoid defaults to rendering the errors in a way that doesn't appear in the output. This means that errors are invisible in the visual editor and in dumps.
• Why don't "mystery #1" errors appear on the page?
  • This turns out to be a Parsoid-specific bug, documented in T337361.
• What do the cite errors each mean?

• Mystery #1: we found 11 cite_error_references_duplicate_key errors in mw-data metadata on de:Ute_Knie (HTML but nothing appears on the page in any editor or rendering. What is this error? Compare the content of each body. Compare various parser outputs.

Error catalog

cite_error_empty_references_define
when there is a <ref> inside <references>, but it does not have any content
Example: <references><ref name="e"></ref></references>

cite_error_group_refs_without_references
when a ref group has no <references> tag
Example: <ref group="c">Foo</ref>

cite_error_included_ref
if the <ref> tag is unbalanced, that means a <ref> is not followed by a </ref>
Example: <ref><ref></ref>

cite_error_included_references
if a <references> tag is found inside another
Example: TODO

cite_error_no_link_label_group
Gone since T377454.

cite_error_ref_invalid_dir
when ref tag contain dir attribute with invalid value
Example: <ref dir="foo">Bar</ref>

cite_error_ref_no_input
when ref tags without names have no content
Example: <ref></ref>

cite_error_ref_no_key
when ref tags without any content (that is <ref/>) are used without a name
Example: <ref />

cite_error_ref_numeric_key
if the name of a ref tag only contains digits
Example: <ref name="123">Foo</ref>

cite_error_ref_too_many_keys
When an unknown attribute is used in a ref tag, or follows and name are used together.
Example: <ref foo="bar">Foo</ref>

cite_error_references_duplicate_key
Relevance: Conflicting names, e.g. when copy-pasting to VE, but it doesn’t understand references from templates.
when multiple refs with same name exist but with different content
Example:

<ref name="f">Foo</ref>
<ref name="f">Bar</ref>
<references />

cite_error_references_group_mismatch
when a <ref> has a different group than its enclosing <references>
Example: <references group="a"><ref group="b">Foo</ref></references>

cite_error_references_invalid_parameters
when invalid parameters are used in the references tag
Example: <references foo="bar" />

cite_error_references_missing_group
Gone since T269531.

cite_error_references_missing_key
Relevance: Orphans list-defined reference, i.e. wanted to re-use but didn’t.
when using something like <references><ref name="refname">...</ref></references> and the reference <ref name="refname"/> is not used anywhere in the page

Example 1 (follow):

<ref follow="theName">theFollows</ref>
<references>
<ref name="theName">theValue</ref>
</references>

Example 2 (in references):

<ref name="foo" group="2">Foo</ref>
<references group="2">
<ref name="unused">BAR</ref>
</references>

cite_error_references_no_backlink_label
Gone since T385669.

cite_error_references_no_key
when a <ref> inside <references> does not have a name attribute
Example: <references><ref>Foo</ref></references>

cite_error_references_no_text
Relevance: Trying to re-use a non-existing ref. Copy-paste error?
when the tag <ref name="something"/> is used with the name-option specified and no other tag specifies a cite-text for this name
Example:

<ref name="g"></ref>
<references />