Fix preview crash on re-render (BadResource error) #13967

cderv · 2026-01-28T18:32:03Z

When re-rendering a file during quarto preview in a project, the preview crashes with BadResource: Bad resource ID from the Sass cache Deno.Kv operations.

Root Cause

This is a regression from #13804 which changed how ProjectContext is managed during preview. That PR made the project context persist across re-renders (instead of being recreated each time), but renderForPreview() still called renderResult.context.cleanup() after each render.

The cleanup closes shared resources like the SassCache Deno.Kv handle. On subsequent re-renders, the code returns the cached SassCache instance whose KV handle was already closed, causing the BadResource error when calling kv.get().

Fix

Remove the cleanup() call from renderForPreview() - the project context is owned by preview() and should only be cleaned up when preview exits via onCleanup()
Invalidate the fileInformationCache entry for the rendered file before each render - since cleanup() previously cleared all caches (including fileInformationCache), removing the call means stale file content would be reused. The cache entry for the specific file being rendered is now deleted so changes are picked up.

Fixes #13955

posit-snyk-bot · 2026-01-28T18:32:27Z

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cderv · 2026-01-29T14:57:02Z

src/project/project-shared.ts

This normalization is related to

Single file rendering vs Project rendering: inconsistency in input path which is relative vs absolute #12401

Windows / Linux and Project vs Single file leads to different paths. I tried to make that works because we need to delete by key, so it is important to get the right path, but obviously this modify current behavior, and leads to failed test.

cderv · 2026-01-29T17:29:11Z

😞 I tried to preview quarto-web with this PR, and I still encounter some issue with sass Kv, we may have an other issue.

cderv · 2026-01-29T17:51:27Z

Ok so I don't manage to reproduce, maybe it was a bad state. quarto preview on quarto-web works ok to navigate;

However, as expected, change .scss file for example does trigger re-render, but the change are not shown. Though I am really not even sure this working with current 1.8 as discussed.

However, testing quarto render on a single doc, no project fails to udpate.

And I am quite convinced this is because of this normalize path key. So not good to merge yet

Quarto Project => quarto preview works
Single file => quarto preview does not show change in output file.

cderv · 2026-01-29T18:01:50Z

🤦 It is late for me and I spent much time of this, now this should really be non-normalized path for lookup.

I'll test tomorrow manually the behavior

cderv · 2026-01-30T15:41:19Z

So the normalizing is done correctly this time. All tests passes. I am currently checking other preview features and we're good!

cderv · 2026-01-30T17:24:07Z

Manual Testing Summary

Tested using Claude Code with Chrome DevTools MCP to verify live browser updates.

Test Matrix

Scenario	Code Path	Result
Project context (with `_quarto.yml`)	`renderProject`	✅
Single file (no `_quarto.yml`)	`singleFileProjectContext`	✅
RevealJS format	Different output handling	✅

Detailed Results

Input file types tested:

.qmd files ✅
.md files ✅
.ipynb files ✅

Resource files tested:

.scss custom styles ✅
.lua filters ✅
Image files ⚠️ (reload only, no re-render - expected)

Stress tests:

Rapid edits (5+ quick saves) ✅
Stop and restart preview ✅

Key Finding

No BadResource errors across 15+ render cycles in all scenarios.

Pre-existing Issues Found (NOT regressions)

These were verified against baseline 1.9.17 - same behavior:

Partial files ({{< include _partial.qmd >}}) not watched
_quarto.yml changes not detected

cderv · 2026-01-30T18:30:58Z

Yeah all tests passes with latest change too. If this is good TS change, then we can merge and build the next prerelease !

cscheid

This looks great 🚀

…tion and reuse.

…t each render in preview mode the project context is owned by `preview()` and cleaned up when preview exits. Calling `cleanup()` here would close shared resources (like SassCache KV handles) causing BadResource errors on subsequent re-renders (#13955).

… ensure changes are picked up in preview mode

cderv · 2026-01-30T19:12:18Z

Thank you. I'll clean the branch and merge

Documents the project context lifecycle fix from #13804 that resolves intermittent preview crashes when editing notebooks and qmd files.

and add a debug log message when we do so.

The fileInformationCache was using inconsistent path formats as keys, causing cache misses during preview. On Windows, paths could be stored with forward slashes but looked up with backslashes (or vice versa). Apply normalizePath() at all cache access points: - ensureFileInformationCache() in project-shared.ts (entry point) - renderForPreview() deletion in preview.ts - populateFileInformation() and inspectDocumentConfig() in inspect.ts - cleanupNotebook() in jupyter.ts Add unit tests for fileInformationCache behavior with reusable createMockProjectContext() factory in tests/unit/project/utils.ts. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Move normalization logic from call sites into the cache class itself. The class now overrides get/has/set/delete to normalize keys automatically, ensuring consistent cache behavior without requiring callers to remember to normalize paths. Also fix ensureFileInformationCache fallback to create FileInformationCacheMap (not plain Map) and add test coverage for this case. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cderv force-pushed the fix/issue-13955 branch from de69c0b to b796ec4 Compare January 29, 2026 13:46

cderv commented Jan 29, 2026

View reviewed changes

cderv mentioned this pull request Jan 30, 2026

Single file rendering vs Project rendering: inconsistency in input path which is relative vs absolute #12401

Open

cderv marked this pull request as ready for review January 30, 2026 17:49

cderv requested a review from cscheid January 30, 2026 17:50

cscheid approved these changes Jan 30, 2026

View reviewed changes

cderv added 4 commits January 30, 2026 20:11

log, debug - Add more debug step log messages to track SassCache crea…

aa1cae0

…tion and reuse.

preview, projectContext - Invalidate file cache for rendered files to…

dde993d

… ensure changes are picked up in preview mode

saasCache, log - simplify logging for sassCache

c7c7c41

cderv and others added 7 commits January 30, 2026 20:17

changelog - Add preview improvements entry

5344ad8

Documents the project context lifecycle fix from #13804 that resolves intermittent preview crashes when editing notebooks and qmd files.

Use unnormalized paths when removing fileInformationCache entries

b3edfe3

and add a debug log message when we do so.

tests - new .gitignore addition from running tests with recent quarto

69f90b0

tests - Correct copyight year

d846d86

docs - add comments about new FileInformationCacheMap class to explain

979807e

cderv force-pushed the fix/issue-13955 branch from d1f0f14 to 979807e Compare January 30, 2026 19:33

cderv merged commit 0ff33a3 into main Jan 30, 2026
51 checks passed

cderv deleted the fix/issue-13955 branch January 30, 2026 20:22

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Fix preview crash on re-render (BadResource error) #13967

Fix preview crash on re-render (BadResource error) #13967

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Fix preview crash on re-render (BadResource error) #13967

Fix preview crash on re-render (BadResource error) #13967

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cderv commented Jan 28, 2026

Root Cause

Fix

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Manual Testing Summary

Test Matrix

Detailed Results

Key Finding

Pre-existing Issues Found (NOT regressions)

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