Fix line breaks appearing after inline images in compiled PDF

.github/workflows/myst.yml

@@ -32,8 +32,16 @@ jobs:
 
       # The PDF builds compile under LuaLaTeX and rely on
       # \DocumentMetadata, which the LaTeX kernel only ships with
-      # TeX Live 2022+. Ubuntu's apt packages still ship 2023, so
-      # install TeX Live 2025 from upstream via zauguin's action.
+      # TeX Live 2022+. Ubuntu's apt packages lag well behind, so
+      # install current TeX Live from upstream via zauguin's action.
+      #
+      # NOTE: `repository` pins the live tlnet mirror, which always
+      # serves the *current* TeX Live release — so texlive_version must
+      # match it. When TeX Live rolls over each spring, tlnet switches
+      # to the new year, the old version pin stops matching, and
+      # renamed/removed packages fail `tlmgr install` (this exact
+      # combination broke the 2025→2026 rollover). At rollover: bump
+      # texlive_version and re-check the package list for renames.
       #
       # Package list rationale: the *recommended* collections cover
       # nearly everything we need (geometry, hyperref, koma-script,
@@ -43,10 +51,14 @@ jobs:
       # those collections. We deliberately avoid collection-latexextra
       # / collection-fontsextra (~2,700 extra packages, ~12 min, and
       # one of them tripped up format-file generation in TL 2025).
-      - name: Install TeX Live 2025
+      #
+      # TL 2026 renames: pdfmanagement-testphase -> pdfmanagement,
+      # sourceserifpro -> sourceserif (ships a sourceserifpro.sty
+      # compatibility alias, so template.tex is unchanged).
+      - name: Install TeX Live 2026
         uses: zauguin/install-texlive@v4
         with:
-          texlive_version: 2025
+          texlive_version: 2026
           # Pin a known-reliable US CTAN mirror. zauguin's default
           # mirror probe has been failing intermittently with
           # "No mirror available"; hardcoding RIT bypasses it.
@@ -64,8 +76,8 @@ jobs:
             framed
             iftex
             imakeidx
-            pdfmanagement-testphase
-            sourceserifpro
+            pdfmanagement
+            sourceserif
             tagpdf
             textpos
             titlesec

_latex-template/template.tex

@@ -181,6 +181,16 @@
     \snaporigincludegraphics[height=#1\baselineskip]{#2}%
   }%
 }
+% myst-to-tex closes every image node with a blank line — a forced \par —
+% which would break the paragraph after each inline image. The latex-shims
+% plugin brackets inline images with \snapinlineopen/\snapinlineclose:
+% inside the pair \par is a no-op, so the serializer's blank line is inert,
+% and \unskip drops the stray inter-word glue from the newline the
+% serializer emits right after \includegraphics (the following text node
+% carries its own leading space when one belongs there). A real paragraph
+% end is serialized after \snapinlineclose, so it still breaks normally.
+\newcommand{\snapinlineopen}{\begingroup\let\par\relax}
+\newcommand{\snapinlineclose}{\unskip\endgroup}
 \makeatletter
 \def\snap@inline@a{width=0.001\linewidth}% image-inline      -> 1.5x
 \def\snap@inline@b{width=0.002\linewidth}% image-inline-tall -> 2.4x

_support/plugins/latex-shims.mjs

@@ -380,6 +380,38 @@ const latexShimsTransform = {
         imageNode.width = normalizeWidth(imageNode.width);
       }
     });
+
+    // 6. Keep inline images inline. myst-to-tex closes EVERY image node
+    //    with a blank line (a forced \par in TeX), so an inline image
+    //    mid-sentence would split its paragraph and put a line break
+    //    after the image. We can't stop the serializer from emitting the
+    //    blank line without forking myst-to-tex, but we can defuse it:
+    //    bracket each inline image with raw-TeX siblings
+    //    (\snapinlineopen / \snapinlineclose, defined in template.tex)
+    //    that scope a no-op \par around the image. A genuine paragraph
+    //    end still breaks normally because it is serialized after the
+    //    closing marker. Nodes are tagged so re-runs of this transform
+    //    (one per export pipeline) don't wrap twice.
+    walkAll(tree, (node) => {
+      if (!Array.isArray(node.children)) return;
+      for (let i = 0; i < node.children.length; i++) {
+        const child = node.children[i];
+        if (child?.type !== 'image' || child._snapInlineWrapped) continue;
+        if (inlineSentinel(child) == null) continue;
+        child._snapInlineWrapped = true;
+        node.children.splice(i, 0, {
+          type: 'raw',
+          lang: 'tex',
+          tex: '\\snapinlineopen{}',
+        });
+        node.children.splice(i + 2, 0, {
+          type: 'raw',
+          lang: 'tex',
+          tex: '\\snapinlineclose{}',
+        });
+        i += 2;
+      }
+    });
   },
 };