Let use_package() decrement a package dependency.

NEWS.md

@@ -1,6 +1,13 @@
 # usethis (development version)
 
+## Bug fixes and minor improvements
+
+* `use_package()` now decreases a package minimum version required when
+  `min_version` is lower than what is currently specified in the DESCRIPTION
+  file (@jplecavalier, #1957).
+
 * `use_data()` now uses serialization version 3 by default. (@laurabrianna, #2044)
+
 * Reverse dependency checks are only suggested if they exist 
   (#1817, @seankross).
 

R/helpers.R

@@ -62,19 +62,21 @@ use_dependency <- function(package, type, min_version = NULL) {
       "!" = "Package {.pkg {package}} is already listed in
              {.field {existing_type}} in DESCRIPTION; no change made."
     ))
-  } else if (delta == 0 && !is.null(min_version)) {
-    # change version
-    upgrade <- existing_version == "*" ||
-      numeric_version(min_version) > version_spec(existing_version)
-    if (upgrade) {
-      ui_bullets(c(
-        "v" = "Increasing {.pkg {package}} version to {.val {version}} in
-               DESCRIPTION."
-      ))
-      desc$set_dep(package, type, version = version)
-      desc$write()
-      changed <- TRUE
+  } else if (delta == 0 && version_spec(version) != version_spec(existing_version)) {
+    if (version_spec(version) > version_spec(existing_version)) {
+      direction <- "Increasing"
+    } else {
+      direction <- "Decreasing"
     }
+
+    ui_bullets(c(
+      "v" = "{direction} {.pkg {package}} version to {.val {version}} in
+             DESCRIPTION."
+    ))
+    desc$set_dep(package, type, version = version)
+    desc$write()
+    changed <- TRUE
+
   } else if (delta > 0) {
     # moving from, e.g., Suggests to Imports
     ui_bullets(c(
@@ -96,6 +98,7 @@ r_version <- function() {
 }
 
 version_spec <- function(x) {
+  if (x == "*") x <- "0"
   x <- gsub("(<=|<|>=|>|==)\\s*", "", x)
   numeric_version(x)
 }

tests/testthat/_snaps/helpers.md

@@ -26,6 +26,13 @@
     Message
       v Increasing crayon version to ">= 2.0.0" in DESCRIPTION.
 
+---
+
+    Code
+      use_dependency("crayon", "Imports", min_version = "1.0.0")
+    Message
+      v Decreasing crayon version to ">= 1.0.0" in DESCRIPTION.
+
 # use_dependency() upgrades a dependency
 
     Code

tests/testthat/test-helpers.R

@@ -52,7 +52,9 @@ test_that("we message for version change and are silent for same version", {
   expect_snapshot(
     use_dependency("crayon", "Imports", min_version = "2.0.0")
   )
-  expect_silent(use_dependency("crayon", "Imports", min_version = "1.0.0"))
+  expect_snapshot(
+    use_dependency("crayon", "Imports", min_version = "1.0.0")
+  )
 })
 
 ## https://github.com/r-lib/usethis/issues/99