Fix Google Scholar render failure with a CSL JSON bibliography (#15125)

With google-scholar enabled, rendering a document that cites from a
CSL JSON bibliography (.json) failed with "JSON parse error: Error in
$: mempty". The Scholar metadata ran `pandoc <file> -t csljson` without
an input format, so pandoc read the .json file as its own JSON AST.
Pass `-f csljson` for .json bibliographies.

The conversion dates back to v1.4, so this affected every Scholar
render with a CSL JSON bibliography. The per-page tags and the book
references page both go through it.

See #15118

Author: cderv

news/changelog-1.11.md

@@ -64,6 +64,7 @@ All changes included in 1.11:
 - ([#15108](https://github.com/quarto-dev/quarto-cli/pull/15108)): Fix Google Scholar metadata showing formatting markup such as `<i>` in `citation_reference` tags for bibliography entries, and `undefined` as the book title of a chapter without one.
 - ([#15115](https://github.com/quarto-dev/quarto-cli/pull/15115)): Fix Google Scholar writing two `citation_reference` tags for a reference defined in two bibliography files. The tag now describes the entry Pandoc renders.
 - ([#15118](https://github.com/quarto-dev/quarto-cli/pull/15118)): Fix Google Scholar metadata missing the first and last page of bibliography entries, and giving wrong pages for a citation `page` written with an en-dash or as a page list.
+- ([#15125](https://github.com/quarto-dev/quarto-cli/pull/15125)): Fix Google Scholar metadata failing the render with a CSL JSON (`.json`) bibliography.
 
 ### `pdf`
 

src/core/bibliography.ts

@@ -7,7 +7,7 @@
  * Adapted from: https://github.com/watson/ci-info
  */
 
-import { dirname, isAbsolute, join } from "../deno_ral/path.ts";
+import { dirname, extname, isAbsolute, join } from "../deno_ral/path.ts";
 import { kBibliography } from "../config/constants.ts";
 import { Metadata } from "../config/types.ts";
 import { asArray } from "./array.ts";
@@ -85,6 +85,11 @@ export async function renderToCSLJSON(
     // in which case just leave it alone (otherwise it is cwd relative)
     const biblioPath = join(dir, biblio);
     const cmd = [pandocBinaryPath()];
+    // Without -f, pandoc reads a .json input as its own JSON AST
+    if (extname(biblioPath).toLowerCase() === ".json") {
+      cmd.push("-f");
+      cmd.push("csljson");
+    }
     cmd.push(
       isAbsolute(biblioPath) ? biblioPath : join(Deno.cwd(), biblioPath),
     );

tests/docs/smoke-all/2026/10/14/scholar-references/csl-json.qmd

@@ -0,0 +1,15 @@
+---
+title: Scholar metadata for a CSL JSON bibliography
+format: html
+google-scholar: true
+bibliography: references.json
+_quarto:
+  tests:
+    html:
+      ensureHtmlElements:
+        - ['meta[name="citation_reference"][content*="citation_author=Alice Smith;"]']
+---
+
+The bibliography is a CSL JSON file. Pandoc reads a bare `.json` input as its own JSON AST, so the Scholar reference tags need the bibliography read explicitly as CSL JSON.
+
+This article cites one work [@cited].

tests/docs/smoke-all/2026/10/14/scholar-references/references.json

@@ -0,0 +1,9 @@
+[
+  {
+    "id": "cited",
+    "type": "article-journal",
+    "title": "Cited reference",
+    "author": [{ "family": "Smith", "given": "Alice" }],
+    "issued": { "date-parts": [[2024]] }
+  }
+]