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Check analytical outputs for drift against a certified baseline

Source: R/certify.R
check_drift.Rd

Re-hashes a set of named R objects and compares them against a previously stored certification. Reports which outputs are unchanged ("ok"), have changed ("drifted"), are present in the baseline but not supplied ("missing"), or are new outputs not in the baseline ("new").

For numeric outputs whose hashes differ, check_drift() falls back to an element-wise absolute difference comparison using tolerance. This makes drift detection robust to benign floating-point variation across platforms (e.g. Linux CI vs macOS local), while still catching genuine numerical changes. The fallback requires that the certification was created with certify() version >= 0.2.0, which stores raw values alongside hashes.

Usage

check_drift(
  outputs,
  against = "latest",
  file = ".reproducr",
  tolerance = 1e-10
)

Arguments

outputs

A fully named list of current R objects – the same names used in the certify() call being compared against.

against

character(1). The certification tag to compare against. Use "latest" (the default) to automatically select the most recently added certification.

file

character(1). Base path of the certification store. Default ".reproducr" (reads .reproducr.rds).

tolerance

numeric(1). Numeric tolerance for element-wise comparison of numeric outputs whose hashes differ. Outputs whose maximum absolute difference is within tolerance are reported as "ok". Set to 0 for exact hash matching only. Default 1e-10.

Value

Invisibly returns a data.frame of class c("drift_report", "data.frame") with columns output, status ("ok", "drifted", "missing", "new"), max_delta, and note. Also emits a summary via message().

See also

certify() to create a baseline; list_certs() to see available tags.

Examples

cert_file <- tempfile()
model <- lm(mpg ~ wt, data = mtcars)

certify(list(coefs = coef(model)), tag = "v1", file = cert_file)
#> reproducr: certified 1 output(s) [2026-06-20] under tag 'v1'

# Same outputs -- should report "ok"
result <- check_drift(list(coefs = coef(model)),
  against = "v1", file = cert_file
)
#> -- reproducr drift check vs 'v1' --
#>   Verdict  : ALL OUTPUTS MATCH
#>   OK       : 1
#>   Drifted  : 0
#>   Missing  : 0
#>   New      : 0
print(result)
#> 
#> -- reproducr drift report --
#> 
#> [OK]      coefs
#> 

# Different model -- should report "drifted"
model2 <- lm(mpg ~ hp, data = mtcars)
check_drift(list(coefs = coef(model2)),
  against = "v1", file = cert_file
)
#> -- reproducr drift check vs 'v1' --
#>   Verdict  : DRIFT DETECTED
#>   OK       : 0
#>   Drifted  : 1
#>   Missing  : 0
#>   New      : 0
#>   Drifted outputs:
#>     - coefs