Vitest v4 deps.optimizer.ssr.include missing sourcemaps

You will need Node 24.11.0 and pnpm. Assuming nvm and corepack:

nvm use
corepack enable

pnpm install
pnpm test

Expect to see a cascade of sourcemap warnings, like this (the files do have sourcemaps, and those paths are valid, by manual inspection):

Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/domutils@3.2.2/node_modules/domutils/lib/esm/index.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/domutils@3.2.2/node_modules/domutils/lib/esm/stringify.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/entities@4.5.0/node_modules/entities/lib/esm/index.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/entities@4.5.0/node_modules/entities/lib/esm/decode.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/entities@4.5.0/node_modules/entities/lib/esm/generated/decode-data-html.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/entities@4.5.0/node_modules/entities/lib/esm/generated/decode-data-xml.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/entities@4.5.0/node_modules/entities/lib/esm/decode_codepoint.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/entities@4.5.0/node_modules/entities/lib/esm/encode.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/entities@4.5.0/node_modules/entities/lib/esm/generated/encode-html.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/entities@4.5.0/node_modules/entities/lib/esm/escape.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/domutils@3.2.2/node_modules/domutils/lib/esm/traversal.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/domutils@3.2.2/node_modules/domutils/lib/esm/manipulation.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/domutils@3.2.2/node_modules/domutils/lib/esm/querying.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/domutils@3.2.2/node_modules/domutils/lib/esm/legacy.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/domutils@3.2.2/node_modules/domutils/lib/esm/helpers.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/domutils@3.2.2/node_modules/domutils/lib/esm/feeds.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/cheerio-select@2.1.0/node_modules/cheerio-select/lib/esm/index.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/index.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/compile.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/sort.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/general.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/attributes.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/pseudo-selectors/index.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/pseudo-selectors/filters.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/nth-check@2.1.1/node_modules/nth-check/lib/esm/index.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/nth-check@2.1.1/node_modules/nth-check/lib/esm/parse.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/nth-check@2.1.1/node_modules/nth-check/lib/esm/compile.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/pseudo-selectors/pseudos.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/pseudo-selectors/aliases.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/css-select@5.2.2/node_modules/css-select/lib/esm/pseudo-selectors/subselects.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/cheerio-select@2.1.0/node_modules/cheerio-select/lib/esm/helpers.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/cheerio-select@2.1.0/node_modules/cheerio-select/lib/esm/positionals.js" points to missing source files
20:51:27 [vite] (ssr) Failed to load source map for /Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/parse5-parser-stream@7.1.2/node_modules/parse5-parser-stream/dist/index.js.
Error: An error occurred while trying to read the map file at index.js.map
Error: ENOENT: no such file or directory, open '/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/parse5-parser-stream@7.1.2/node_modules/parse5-parser-stream/dist/index.js.map'
    at open (node:internal/fs/promises:642:25)
    at Object.readFile (node:internal/fs/promises:1279:14)
    at extractSourcemapFromFile (file:///Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/vite@7.2.2/node_modules/vite/dist/node/chunks/config.js:8265:65)
    at loadAndTransform (file:///Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/vite@7.2.2/node_modules/vite/dist/node/chunks/config.js:23258:22)
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/encoding-sniffer@0.2.1/node_modules/encoding-sniffer/dist/esm/index.js" points to missing source files
Sourcemap for "/Users/fotis/oss/vitest-optimizer-sourcemap/node_modules/.pnpm/encoding-sniffer@0.2.1/node_modules/encoding-sniffer/dist/esm/sniffer.js" points to missing source files

Conversely, if you install vitest v3 (pnpm add -DE vitest@3), you will see no such warnings.