From 85248595e3c70e26f4606838ba75e270a6c41e29 Mon Sep 17 00:00:00 2001
From: spacewander <spacewanderlzx@gmail.com>
Date: Thu, 27 Jun 2019 12:33:18 +0800
Subject: [PATCH 1/2] Installation.md: add dependencies section.

---
 Installation.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Installation.md b/Installation.md
index 4b060d9b4..d05b89e40 100644
--- a/Installation.md
+++ b/Installation.md
@@ -1,5 +1,14 @@
 # Installing git-extras
 
+## Dependencies
+
+Some commands require extra dependencies which are unavailable in some platforms.
+You may need to install them manually.
+
+Those dependencies are listed below:
+
+* column
+
 ## Installing with a package manager
 
 ### Debian
@@ -84,6 +93,8 @@ Use the instructions to build from source below. Make sure you are using `gmake`
 
 ## Building from source
 
+Read [Dependencies](#dependencies) and ensure they are installed.
+
 Obtain the git-extras source by cloning [its GitHub repo](https://github.com/tj/git-extras.git) or downloading a tarball of a [release](https://github.com/tj/git-extras/releases). Then install it by doing `make install` from the source tree.
 
 ```bash

From 58d13f88d449e1613fc5d263b1cabfcd87a0bc83 Mon Sep 17 00:00:00 2001
From: spacewander <spacewanderlzx@gmail.com>
Date: Thu, 27 Jun 2019 15:12:30 +0800
Subject: [PATCH 2/2] Makefile: check dependencies before installation.

So that the packager will know what are dependencied when they are
making a new package.
---
 .travis.yml           |  4 ++++
 Makefile              |  9 +++++++--
 check_dependencies.sh | 10 ++++++++++
 3 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100755 check_dependencies.sh

diff --git a/.travis.yml b/.travis.yml
index 2c1a51998..d88b18635 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,10 @@
 os:
   - linux
   - osx
+addons:
+  apt:
+    packages:
+    - bsdmainutils
 script:
   - ./check_integrity.sh $(find bin | cut -b 5- | xargs)
   # Test for the brew release
diff --git a/Makefile b/Makefile
index 4017cdb0b..9eae55f64 100644
--- a/Makefile
+++ b/Makefile
@@ -25,7 +25,12 @@ default: install
 
 docs: $(MAN_HTML) $(MAN_PAGES)
 
-install:
+check:
+	@echo "Check dependencies before installation"
+	@./check_dependencies.sh
+	@echo
+
+install: check
 	@if [ "$(INSTALL_VIA)" = brew ]; then \
 		git apply brew-release.patch || { echo "Can't apply brew release patch"; exit 1; } \
 	fi
@@ -120,4 +125,4 @@ docclean:
 	rm -f man/*.1
 	rm -f man/*.html
 
-.PHONY: default docs clean docclean install uninstall
+.PHONY: default docs clean docclean check install uninstall
diff --git a/check_dependencies.sh b/check_dependencies.sh
new file mode 100755
index 000000000..c1aa52544
--- /dev/null
+++ b/check_dependencies.sh
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+err() {
+    echo >&2 "$1"
+    exit 1
+}
+
+if ! test "$(which column)"; then
+    err "Need to install dependency 'column' before installation"
+fi