Reports what changed between the environment captured by one run and another: the R version, the platform, and every package whose version differs, was added, or disappeared. Use it when a result does not reproduce, to see first whether the software around it changed.
Value
A list of class c("bricklayer_env_diff", "list"):
identical (logical, TRUE when R version, platform and all
package versions agree), r_version (a named length-2 character
vector c(a = , b = ) when they differ, else NULL),
platform (likewise), and packages (a data frame with
character columns package, a, b and change,
where change is "added", "removed" or
"changed"; no rows when nothing differs), and fields
(the names of any other fields that differ, character(0) when
none).
Details
This is the question a failed reproduction actually raises. A manifest records the environment; comparing two manifests by eye across a few hundred packages does not scale, and the one line that matters – a dependency that moved a minor version – is exactly what gets missed.
Versions are compared as strings. A package recorded in b but not
in a (or recorded with an NA version in a) is
"added"; the reverse is "removed". The operating-system
string, the capture time and the random number generator settings are
not compared. Any other field present in only one record, or different
in the two, is named in fields and makes them differ. Rows follow
the order of a's packages, then b's new ones.
Error: a or b that is not a list.
Examples
a <- capenv(c("stats", "utils"))
b <- a
# An environment matches itself.
envdiff(a, b)$identical
#> [1] TRUE
# Stage a moved dependency, an added one and a newer R.
b$packages[["stats"]] <- "0.0.0"
b$packages[["tools"]] <- "4.9.0"
b$r_version <- "9.9.9"
d <- envdiff(a, b)
d$packages
#> package a b change
#> 1 stats 4.6.2 0.0.0 changed
#> 2 tools <NA> 4.9.0 added
d$r_version
#> a b
#> "4.6.2" "9.9.9"
d
#> ╭── Environment diff ─────────────────────────────────────────────────╮
#> │ Status ✗ environments differ │
#> │ R version 4.6.2 -> 9.9.9 │
#> │ │
#> │ package a b change │
#> │ ------- ----- ----- ------- │
#> │ stats 4.6.2 0.0.0 changed │
#> │ tools – 4.9.0 added │
#> │ │
#> │ The records differ: a result may not reproduce until these agree. │
#> │ │
#> │ 2 package difference(s) │
#> ╰─────────────────────────────────────────────────────────────────────╯
# Whole manifests are accepted, not just the environment block.
m <- mkmnf(list(run = "demo"))
envdiff(m, m)$identical
#> [1] TRUE
# anything other than a record is refused
try(envdiff("4.5.1", a))
#> Error : `a` and `b` must be environment records or manifests