Add HOMEBREW_CLEANUP_PERIODIC_FULL_DAYS environment variable

This allows customisation of how often the periodic cleanups are done.

Library/Homebrew/cleanup.rb

@@ -2,6 +2,7 @@
 # frozen_string_literal: true
 
 require "utils/bottles"
+
 require "utils/gems"
 require "formula"
 require "cask/cask_loader"
@@ -12,7 +13,7 @@ module Homebrew
   #
   # @api private
   class Cleanup
-    CLEANUP_DEFAULT_DAYS = 30
+    CLEANUP_DEFAULT_DAYS = Homebrew::EnvConfig.cleanup_periodic_full_days.to_i.freeze
     private_constant :CLEANUP_DEFAULT_DAYS
 
     # {Pathname} refinement with helper functions for cleaning up files.

Library/Homebrew/env_config.rb

@@ -68,6 +68,11 @@ module Homebrew
                      "`~/.profile`, `~/.bash_profile`, or `~/.zshenv`:\n\n" \
                      '    `export HOMEBREW_CASK_OPTS="--appdir=~/Applications --fontdir=/Library/Fonts"`',
       },
+      HOMEBREW_CLEANUP_PERIODIC_FULL_DAYS:    {
+        description: "If set, `brew install`, `brew upgrade` and `brew reinstall` will cleanup all formulae " \
+                     "when this number of days has passed.",
+        default:     30,
+      },
       HOMEBREW_CLEANUP_MAX_AGE_DAYS:          {
         description: "Cleanup all cached files older than this many days.",
         default:     120,
@@ -243,7 +248,8 @@ module Homebrew
       },
       HOMEBREW_NO_INSTALL_CLEANUP:            {
         description: "If set, `brew install`, `brew upgrade` and `brew reinstall` will never automatically " \
-                     "cleanup installed/upgraded/reinstalled formulae or all formulae every 30 days.",
+                     "cleanup installed/upgraded/reinstalled formulae or all formulae every " \
+                     "HOMEBREW_CLEANUP_PERIODIC_FULL_DAYS days.",
         boolean:     true,
       },
       HOMEBREW_PRY:                           {

docs/Manpage.md

@@ -1683,6 +1683,11 @@ example, run `export HOMEBREW_NO_INSECURE_REDIRECT=1` rather than just
 
     `export HOMEBREW_CASK_OPTS="--appdir=~/Applications --fontdir=/Library/Fonts"`
 
+- `HOMEBREW_CLEANUP_PERIODIC_FULL_DAYS`
+  <br>If set, `brew install`, `brew upgrade` and `brew reinstall` will cleanup all formulae when this number of days has passed.
+
+  *Default:* `30`.
+
 - `HOMEBREW_CLEANUP_MAX_AGE_DAYS`
   <br>Cleanup all cached files older than this many days.
 
@@ -1819,7 +1824,7 @@ example, run `export HOMEBREW_NO_INSECURE_REDIRECT=1` rather than just
     *Note:* While ensuring your downloads are fully secure, this is likely to cause from-source SourceForge, some GNU & GNOME-hosted formulae to fail to download.
 
 - `HOMEBREW_NO_INSTALL_CLEANUP`
-  <br>If set, `brew install`, `brew upgrade` and `brew reinstall` will never automatically cleanup installed/upgraded/reinstalled formulae or all formulae every 30 days.
+  <br>If set, `brew install`, `brew upgrade` and `brew reinstall` will never automatically cleanup installed/upgraded/reinstalled formulae or all formulae every HOMEBREW_CLEANUP_PERIODIC_FULL_DAYS days.
 
 - `HOMEBREW_PRY`
   <br>If set, use Pry for the `brew irb` command.

manpages/brew.1

@@ -2356,6 +2356,15 @@ Append these options to all \fBcask\fR commands\. All \fB\-\-*dir\fR options, \f
 \fBexport HOMEBREW_CASK_OPTS="\-\-appdir=~/Applications \-\-fontdir=/Library/Fonts"\fR
 .
 .TP
+\fBHOMEBREW_CLEANUP_PERIODIC_FULL_DAYS\fR
+.
+.br
+If set, \fBbrew install\fR, \fBbrew upgrade\fR and \fBbrew reinstall\fR will cleanup all formulae when this number of days has passed\.
+.
+.IP
+\fIDefault:\fR \fB30\fR\.
+.
+.TP
 \fBHOMEBREW_CLEANUP_MAX_AGE_DAYS\fR
 .
 .br
@@ -2614,7 +2623,7 @@ If set, forbid redirects from secure HTTPS to insecure HTTP\.
 \fBHOMEBREW_NO_INSTALL_CLEANUP\fR
 .
 .br
-If set, \fBbrew install\fR, \fBbrew upgrade\fR and \fBbrew reinstall\fR will never automatically cleanup installed/upgraded/reinstalled formulae or all formulae every 30 days\.
+If set, \fBbrew install\fR, \fBbrew upgrade\fR and \fBbrew reinstall\fR will never automatically cleanup installed/upgraded/reinstalled formulae or all formulae every HOMEBREW_CLEANUP_PERIODIC_FULL_DAYS days\.
 .
 .TP
 \fBHOMEBREW_PRY\fR