Reports

Choose a reporter by how the result will be consumed.

Reporter	Destination	Best for
terminal	stdout	Interactive use and readable CI logs.
jsonl	stdout	Streaming shell pipelines and AI agent workflows.
json	File	Structured integrations and complete run metadata.
html	File	Searchable human review with light and dark themes and per-finding source snippets.
sarif	File	GitHub code scanning and other SARIF 2.1.0 consumers.

vitest-dedup .                                            # terminal
vitest-dedup . --reporters json,html --output reports/vd   # files only
vitest-dedup . --reporters sarif --output reports/vd       # for upload-sarif
vitest-dedup . --reporters jsonl | jq -c 'select(.type == "finding")'

terminal and jsonl both own stdout and cannot be selected together. jsonl combines freely with the file reporters, which never touch stdout.

Page	Contents
Terminal	Layout, footer, detection time, color.
Findings	verdict, fingerprint and the structured fields machine formats carry.
Diagnostic records	--emit-test-fingerprints and --debug-memory.
SARIF	How findings and rules map to SARIF 2.1.0.
Report safety	Why report content is data, and how every reporter sanitizes it.
Baselines and changed-file scoping	--baseline, --update-baseline, --changed-since, --baseline-from-ref.
Incomplete runs and limits	What incomplete means, --fail-on-incomplete, work and memory limits.
Imported runners	Which first-party helper functions are expanded into tests, and what is refused.

Writing files

--output is a filename stem, not a directory: --output reports/vd writes reports/vd.json. Without --output, file reporters use the stem reports/vitest-dedup. Parent directories are created as needed.

• Each report is buffered into a temporary file in its output directory, then atomically replaces the destination after successful serialization and flush.
• A final-component symlink is replaced without writing to its target. Output directories may contain symlinks.
• If writing fails, the previous report remains intact and the run fails.
• Replacement uses temporary-file permissions and does not preserve the previous inode or its metadata.
• Several selected reports are replaced independently.

After every selected file report has been written successfully, file-only runs print Reports written to: followed by indented, sanitized paths. The path spelling and filename-stem behavior are preserved. Runs with terminal or jsonl omit this announcement, leaving stdout to the selected stream reporter.

Diagnostics

Diagnostics stay on stderr: early operational errors, globals detection, incomplete coverage, baseline and changed-file qualifications, and the opt-in cell census. Disabled globals and absent configuration remain silent. Globals detection markers retain their existing wording for corpus tooling. Diagnostic text is plain and sanitized; writer failures are operational errors.

Lists are bounded with explicit omission counts:

• at most 20 immediate read failures
• at most 20 deferred diagnostic messages
• at most 10 wholly excluded files
• at most 10 files containing only statically empty tables

Counts describe all affected messages and files, including omitted entries; display limits do not change analyzed scope, findings or exit policy. Census categories retain their own counts.

verdict and fingerprint

Machine formats carry both. verdict names what a finding claims (redundant, consolidatable, name-collision or similar-uncertain), and fingerprint is its stable identity across runs. Details are on the Findings page.

Determinism

The same admitted input produces byte-identical output, with two exceptions: terminal output includes the detection time unless --no-metrics is set, and the --debug-memory record carries process-dependent figures such as peak RSS. A memory-limited run may admit a different file prefix as process residency changes. Findings are ordered by their participants’ locations (root-relative path, then position), then by rule, then by message. Paths are compared component by component rather than as strings, so the order does not depend on the platform’s separator.