Hongdown 0.5.2

Released on July 28, 2026.

• Fixed a bug where a reference definition shared by a body link and a link inside a footnote could sink to the later footnote's section, leaving the body link's section without its definition. Shared definitions now stay at the end of the first section that uses them, while remaining below footnote definitions when both occur in the same section. [#30, #38]

• Fixed a bug where reference definitions lost angle brackets required by an empty destination, ASCII whitespace, or other targets that cannot be serialized safely in bare form. Those lines no longer represented the original CommonMark reference definitions, and a second formatting pass treated them as ordinary text. These destinations now stay angle-bracketed, preserving their link targets and making formatting idempotent. [#25, #37]

• Fixed a bug where an external inline link whose text contained consecutive whitespace could require two formatting passes to settle. Runs of CommonMark ASCII whitespace in ordinary link text are now collapsed on the first pass, so [a b](https://example.com/) immediately becomes [a b] with a matching definition. [#28, #36]

• Fixed a bug where non-ASCII whitespace at the edge of an inline link's text could leave its generated shortcut reference with no matching definition. Reference labels now follow the parser's edge-whitespace rules, preserving distinct labels and their definitions across formatting runs. [#31, #35]

• Fixed a bug where formatting could silently change a link's destination. Reference labels are generated from the link text, so two links with the same text but different destinations were given the same label, and the later definition overwrote the earlier one. A label is now shared only when the complete target matches, meaning both the URL and the title; otherwise the colliding link gets a numbered label and full reference syntax, as in [guide][guide 2]. [#26, #29]

• Fixed a bug where a numbered label assigned to a colliding link could match unresolved reference syntax elsewhere in the document, silently turning ordinary bracketed text into a link. Numbered label allocation now skips labels already used by unresolved references. [#33, #34]

• Fixed a bug where a reference definition needed by a later section was dropped entirely when an earlier section had already defined the same label with a different destination, leaving the later link pointing at the earlier section's URL. [#26, #29]

• Fixed a bug where reference labels differing only in letter case, such as [Guide] and [guide], were emitted as two separate definitions. Since CommonMark matches reference labels case-insensitively, parsers ignored the second definition and both links resolved to the first URL. Labels are now compared with runs of whitespace collapsed and Unicode case folding applied, the same way the underlying parser resolves them. [#26, #29]

• Fixed a bug where a reference definition placed inside a <!-- hongdown-disable --> region was dropped, leaving the region's links pointing at nothing. Since the loss was stable across runs, --check never reported the damaged file afterwards. The region between the two directives is now copied from the source in one piece instead of being rebuilt block by block, so its reference definitions survive, as do its footnote definitions, interior blank lines, and indentation. (The blank line separating the region from the directives around it is still normalized to exactly one.) [#27, #32]

• Fixed a bug where a reference definition was dropped when the only links using it sat in a region that skips formatting. Those links are copied from the source and never registered the definition they depend on, which silently broke reference-style badges under <!-- hongdown-disable -->, <!-- hongdown-disable-next-line -->, <!-- hongdown-disable-next-section -->, and <!-- hongdown-disable-file -->. [#27, #32]

• Fixed a bug where a link inside a region that skips formatting could have its destination changed by a link outside it. A copied link keeps the label the source gave it, so when both wanted the same label for different destinations the copied one silently lost its target. The formatted link, which can be given a derived label such as [guide][guide 2], now yields instead. [#27, #32]

• Fixed a bug where a directive comment gained an extra blank line above it when it directly followed front matter, and lost the blank line entirely when the only thing above it was a reference definition. [#27, #32]

• Fixed a bug where a block whose formatting was skipped by <!-- hongdown-disable-next-line --> or <!-- hongdown-disable-next-section --> was copied from where its content begins rather than from the start of its lines, losing the indentation and the list or blockquote markers before it. An indented code block came out as a paragraph, and a reference definition the parser had taken out of a list item was dropped altogether. Such a block also gained a blank line on every run, so --check reported a file --write had just written. [#32]

• Fixed a bug where a reference label holding a bracket escaped with a backslash, as in [a\]b], was cut short at that bracket. The link was given a label naming no definition, and the definition itself was written out cut short too, so the next run no longer read it as a definition at all. [#32]