install: submit brew patch to upstream

Follow the atempt of pull request #491

.travis.yml

@@ -1,4 +1,10 @@
 os:
   - linux
   - osx
-script: ./check_integrity.sh $(find bin | cut -b 5- | xargs)
+script:
+  - ./check_integrity.sh $(find bin | cut -b 5- | xargs)
+  # Test for the brew release
+  - mkdir ../release && git archive --format=tar.gz HEAD > ../release/git-extras-release.tar.gz
+  - cd ../release
+  - tar -xzf git-extras-release.tar.gz && make PREFIX=$(pwd) INSTALL_VIA=brew
+  - ./bin/git-extras update | grep "brew upgrade git-extras"

Makefile

@@ -7,6 +7,7 @@ MANS = $(wildcard man/git-*.md)
 MAN_HTML = $(MANS:.md=.html)
 MAN_PAGES = $(MANS:.md=.1)
 CODE_DIR := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
+INSTALL_VIA ?= source
 # Libraries used by all commands
 LIB = "helper/reset-env" "helper/git-extra-utility"
 
@@ -17,6 +18,9 @@ default: install
 docs: $(MAN_HTML) $(MAN_PAGES)
 
 install:
+	@if [ "$(INSTALL_VIA)" = brew ]; then \
+		git apply brew-release.patch || { echo "Can't apply brew release patch"; exit 1; } \
+	fi
 	@mkdir -p $(DESTDIR)$(MANPREFIX)
 	@mkdir -p $(DESTDIR)$(BINPREFIX)
 	@echo "... installing bins to $(DESTDIR)$(BINPREFIX)"

brew-release.patch

@@ -0,0 +1,24 @@
+diff --git a/bin/git-extras b/bin/git-extras
+index e49cd24..4ae28b5 100755
+--- a/bin/git-extras
++++ b/bin/git-extras
+@@ -4,13 +4,12 @@ VERSION="4.3.0"
+ INSTALL_SCRIPT="https://raw.githubusercontent.com/tj/git-extras/master/install.sh"
+
+ update() {
+-  local bin="$(which git-extras)"
+-  local prefix=${bin%/*/*}
+-  local orig=$PWD
+-
+-  curl -s $INSTALL_SCRIPT | PREFIX="$prefix" bash /dev/stdin \
+-    && cd "$orig" \
+-    && echo "... updated git-extras $VERSION -> $(git extras --version)"
++  echo "This git-extras installation is managed by Homebrew."
++  echo "If you'd like to update git-extras, run the following:"
++  echo
++  echo "  brew upgrade git-extras"
++  echo
++  return 1
+ }
+
+ updateForWindows() {