[deadstrobe5]

Description

AbbrBlockprocessor.run records one definition per call and puts the rest of the block back on the stack, so a block of N definitions is re-tested by every block processor N times and the remainder is copied N times. A glossary of abbreviations appended to every page (the setup Material for MkDocs documents with pymdownx.snippets auto_append) hits this on every page.

This records the following definitions in the same pass, the same way consecutive reference definitions were handled in #1678. A later definition is only taken when the block starts with a definition, the later one fits on one line, and it is followed by another definition or the end of the block. In any other case a processor with higher priority could claim the remainder (a Setext underline, a table separator or a definition list line after it), so that definition is left to the next pass and the output does not change. A test covers the Setext case.

Median of 5 alternating runs in one process, CPython 3.14, markdown.Markdown(extensions=[...]).convert():

Document	Before	After
2 KB page + 50 definitions (9 extensions)	5.41 ms	2.18 ms
2 KB page + 200 definitions (9 extensions)	79.5 ms	3.92 ms
2 KB page + 200 definitions (abbr only)	30.3 ms	2.18 ms
10,000 definitions (abbr only, one run)	178 s	0.32 s

Pages without definitions are unchanged. I compared the HTML and the recorded abbreviations of the old and new code on 50,000 generated documents (definitions inside lists, block quotes and indented blocks, empty and '' titles, multi-line definitions, mixed with tables, headers and definition lists) and found no differences.

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Checklist

• This PR follows the contribution guidelines.
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[waylan]

This is not the correct behavior. The correct output should be:

<p>===</p>

[deadstrobe5]

Agreed, fixed in 796d415 (plus c66f873 for line length). The processor now takes every consecutive definition, whatever follows, so that input gives <p>===</p>. I dropped the rule that left the last definition for another processor, which was there only to keep the old output.

Current master is inconsistent here: two definitions before === already give <p>===</p>, but with three or more, master turns the last definition into an <h1>. I added a test for the three-definition case (it fails on master and passes here). Against master, the output differs only in this pattern: 19 of 4,168 documents (the test fixtures, the docs, and random mixes of definitions, headers, lists and text), all of them definitions followed by ===. 200 definitions still go from 15.5 ms to 0.63 ms. Also merged master to fix the changelog conflict.

[waylan]

Now that there is no code between these 2 loops, they should be able to be combined into a single loop.

Although, why not just call finditer up on line 160 and then loop through the results?