HOMEBREW_NO_CHECK_INSTALLED_DEPENDENTS: add variable.

Add an opt-out of this behaviour.

Library/Homebrew/env_config.rb

@@ -207,6 +207,11 @@ module Homebrew
                      "falling back to building from source.",
         boolean:     true,
       },
+      HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK: {
+        description: "If set, do not check for broken dependents after installing, upgrading or reinstalling " \
+                     "formulae.",
+        boolean:     true,
+      },
       HOMEBREW_NO_COLOR:                      {
         description:  "If set, do not print text with colour added.",
         default_text: "`$NO_COLOR`.",

Library/Homebrew/upgrade.rb

@@ -135,6 +135,8 @@ module Homebrew
     end
 
     def check_installed_dependents(args:)
+      return if Homebrew::EnvConfig.no_installed_dependents_check?
+
       installed_formulae = FormulaInstaller.installed.to_a
       return if installed_formulae.empty?
 

docs/Manpage.md

@@ -1728,6 +1728,9 @@ For example, you might add something like the following to your ~/.profile, ~/.b
   * `HOMEBREW_NO_BOTTLE_SOURCE_FALLBACK`:
     If set, fail on the failure of installation from a bottle rather than falling back to building from source.
 
+  * `HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK`:
+    If set, do not check for broken dependents after installing, upgrading or reinstalling formulae.
+
   * `HOMEBREW_NO_COLOR`:
     If set, do not print text with colour added.
 

manpages/brew.1

@@ -2418,6 +2418,10 @@ If set, do not automatically update before running \fBbrew install\fR, \fBbrew u
 If set, fail on the failure of installation from a bottle rather than falling back to building from source\.
 .
 .TP
+\fBHOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK\fR
+If set, do not check for broken dependents after installing, upgrading or reinstalling formulae\.
+.
+.TP
 \fBHOMEBREW_NO_COLOR\fR
 If set, do not print text with colour added\.
 .