Add --fresh option to brew install

When invoked, this option will ensure brew doesn't re-use any options from
previous installs of a formula.

Library/Contributions/brew_bash_completion.sh

@@ -127,7 +127,7 @@ _brew_to_completion()
             local opts=$(
                 local opts=(--force --verbose --debug --use-clang --use-gcc
                     --use-llvm --ignore-dependencies --build-from-source --HEAD
-                    --interactive $(brew options --compact "$prev"))
+                    --interactive --fresh $(brew options --compact "$prev"))
 
                 # options that make sense with '--interactive'
                 if [[ "${COMP_WORDS[*]}" =~ "--interactive" ]]; then

Library/Contributions/manpages/brew.1.md

@@ -135,7 +135,7 @@ For the full command list, see the COMMANDS section.
   * `info` <URL>:
     Print the name and version that will be detected for <URL>.
 
-  * `install [--force] [--debug] [--ignore-dependencies] [--use-clang] [--use-gcc] [--use-llvm] [--build-from-source] [--HEAD]` <formula>:
+  * `install [--force] [--debug] [--ignore-dependencies] [--fresh] [--use-clang] [--use-gcc] [--use-llvm] [--build-from-source] [--HEAD]` <formula>:
     Install <formula>.
 
     <formula> is usually the name of the formula to install, but may also be
@@ -152,6 +152,9 @@ For the full command list, see the COMMANDS section.
     any kind. If they are not already present, the formula will probably fail
     to install.
 
+    If `--fresh` is passed, the installation process will not re-use any
+    options from previous installs.
+
     If `--use-clang` is passed, attempt to compile using clang.
 
     If `--use-gcc` is passed, attempt to compile using GCC. This is useful for

Library/Homebrew/formula_installer.rb

@@ -245,8 +245,9 @@ class FormulaInstaller
   # This method gives us a chance to pre-process command line arguments before the
   # installer forks and `Formula.install` kicks in.
   def filtered_args
-    # Did the user actually pass the formula this installer is considering on
+    # Returns true if the formula attached to this installer was explicitly
-    # the command line?
+    # passed on the command line by the user as opposed to being automatically
+    # added to satisfy a dependency.
     def explicitly_requested?
       # `ARGV.formulae` will throw an exception if it comes up with an empty
       # list.
@@ -257,13 +258,23 @@ class FormulaInstaller
       return false if ARGV.named.empty?
       ARGV.formulae.include? f
     end
-    previous_install = Tab.for_formula f
 
     args = ARGV.clone
-    args.concat previous_install.used_options
-    args.uniq! # Just in case some dupes were added
 
-    %w[--HEAD --verbose -v --debug -d --interactive -i].each {|f| args.delete f} unless explicitly_requested?
+    %w[
+      --debug -d
+      --fresh
+      --HEAD
+      --interactive -i
+      --verbose -v
+    ].each {|flag| args.delete flag} unless explicitly_requested?
+
+    unless args.include? '--fresh'
+      previous_install = Tab.for_formula f
+      args.concat previous_install.used_options
+    end
+
+    args.uniq! # Just in case some dupes slipped by
 
     return args
   end

share/man/man1/brew.1

@@ -158,7 +158,7 @@ To view formula history locally: \fBbrew log \-p <formula>\fR\.
 Print the name and version that will be detected for \fIURL\fR\.
 .
 .TP
-\fBinstall [\-\-force] [\-\-debug] [\-\-ignore\-dependencies] [\-\-use\-clang] [\-\-use\-gcc] [\-\-use\-llvm] [\-\-build\-from\-source] [\-\-HEAD]\fR \fIformula\fR
+\fBinstall [\-\-force] [\-\-debug] [\-\-ignore\-dependencies] [\-\-fresh] [\-\-use\-clang] [\-\-use\-gcc] [\-\-use\-llvm] [\-\-build\-from\-source] [\-\-HEAD]\fR \fIformula\fR
 Install \fIformula\fR\.
 .
 .IP
@@ -174,6 +174,9 @@ If \fB\-\-debug\fR is passed and brewing fails, open a shell inside the temporar
 If \fB\-\-ignore\-dependencies\fR is passed, skip installing any dependencies of any kind\. If they are not already present, the formula will probably fail to install\.
 .
 .IP
+If \fB\-\-fresh\fR is passed, the installation process will not re\-use any options from previous installs\.
+.
+.IP
 If \fB\-\-use\-clang\fR is passed, attempt to compile using clang\.
 .
 .IP