Auto-update when running `brew install`/`upgrade`.

Also, slightly tweak the behavior of `brew update` in this case so that
it doesn't print annoying output and still allows the `brew edit` flow
for people with `HOMEBREW_DEVELOPER` set.

2 files changed, 32 insertions, 5 deletions

diff --git a/Library/Homebrew/cmd/update-report.rb b/Library/Homebrew/cmd/update-report.rb
index 7aa5a528b..4d3b280f9 100644
--- a/Library/Homebrew/cmd/update-report.rb
+++ b/Library/Homebrew/cmd/update-report.rb
@@ -4,6 +4,13 @@ require "formulary"
 require "descriptions"
 
 module Homebrew
+  def update_preinstall_header
+    @header_already_printed ||= begin
+      ohai "Auto-updated Homebrew!" if ARGV.include?("--preinstall")
+      true
+    end
+  end
+
   def update_report
     install_core_tap_if_necessary
 
@@ -17,6 +24,7 @@ module Homebrew
     end
 
     if initial_revision != current_revision
+      update_preinstall_header
       puts "Updated Homebrew from #{shorten_revision(initial_revision)} to #{shorten_revision(current_revision)}."
       updated = true
     end
@@ -37,13 +45,14 @@ module Homebrew
     end
 
     unless updated_taps.empty?
+      update_preinstall_header
       puts "Updated #{updated_taps.size} tap#{plural(updated_taps.size)} " \
            "(#{updated_taps.join(", ")})."
       updated = true
     end
 
     if !updated
-      puts "Already up-to-date."
+      puts "Already up-to-date." unless ARGV.include?("--preinstall")
     elsif hub.empty?
       puts "No changes to formulae."
     else
diff --git a/Library/Homebrew/cmd/update.sh b/Library/Homebrew/cmd/update.sh
index a0c7cc7e7..a36b25fb0 100644
--- a/Library/Homebrew/cmd/update.sh
+++ b/Library/Homebrew/cmd/update.sh
@@ -213,7 +213,14 @@ pull() {
 
   trap '' SIGINT
 
-  pop_stash_message
+  if [[ -n "$HOMEBREW_DEVELOPER" ]] &&
+     [[ "$INITIAL_BRANCH" != "$UPSTREAM_BRANCH" && -n "$INITIAL_BRANCH" ]]
+  then
+    git checkout "${QUIET_ARGS[@]}" "$INITIAL_BRANCH"
+    pop_stash
+  else
+    pop_stash_message
+  fi
 
   trap - SIGINT
 }
@@ -231,6 +238,7 @@ homebrew-update() {
       --debug) HOMEBREW_DEBUG=1;;
       --rebase) HOMEBREW_REBASE=1 ;;
       --simulate-from-current-branch) HOMEBREW_SIMULATE_FROM_CURRENT_BRANCH=1 ;;
+      --preinstall) HOMEBREW_UPDATE_PREINSTALL=1 ;;
       --*) ;;
       -*)
         [[ "$option" = *v* ]] && HOMEBREW_VERBOSE=1;
@@ -316,11 +324,21 @@ EOS
            --header "If-None-Match: \"$UPSTREAM_BRANCH_LOCAL_SHA\"" \
            "https://api.github.com/repos/$UPSTREAM_REPOSITORY/commits/$UPSTREAM_BRANCH")"
         [[ "$UPSTREAM_SHA_HTTP_CODE" = "304" ]] && exit
+      elif [[ -n "$HOMEBREW_UPDATE_PREINSTALL" ]]
+      then
+        # Don't try to do a `git fetch` that may take longer than expected.
+        exit
       fi
 
-      git fetch --force "${QUIET_ARGS[@]}" origin \
-        "refs/heads/$UPSTREAM_BRANCH:refs/remotes/origin/$UPSTREAM_BRANCH" || \
-          odie "Fetching $DIR failed!"
+      if [[ -n "$HOMEBREW_UPDATE_PREINSTALL" ]]
+      then
+        git fetch --force "${QUIET_ARGS[@]}" origin \
+          "refs/heads/$UPSTREAM_BRANCH:refs/remotes/origin/$UPSTREAM_BRANCH" 2>/dev/null
+      else
+        git fetch --force "${QUIET_ARGS[@]}" origin \
+          "refs/heads/$UPSTREAM_BRANCH:refs/remotes/origin/$UPSTREAM_BRANCH" || \
+            odie "Fetching $DIR failed!"
+      fi
     ) &
   done