Use brew upgrade instead of install if formula is outdated (#22)

cider/_sh.py

@@ -9,11 +9,14 @@
 import json
 import os
 import pwd
+import re
 import subprocess
 import yaml
 
 JSONDecodeError = ValueError
 
+_OUTDATED_RE = re.compile(r' \(\d.*\)$')
+
 
 class Brew(object):
     def __init__(self, cask=None, debug=None, verbose=None, env=None):
@@ -43,15 +46,16 @@ def __spawn(self, cmd, cmdargs, prompt=None, check_output=None):
     def __assert_no_cask(self, cmd):
         assert not self.cask, "no such command: `brew cask {0}`".format(cmd)
 
-    def safe_install(self, formula, warn=None):
+    def safe_install(self, formula, warn=None, outdated=False):
         warn = warn if warn is not None else False
         try:
             prompt = None
+            cmd = "install" if not outdated else "upgrade"
             if not warn:
                 prompt = "Failed to install {0}. Continue? [y/N]".format(
                     formula
                 )
-            return self.__spawn("install", formula.split(" "), prompt)
+            return self.__spawn(cmd, formula.split(" "), prompt)
         except CalledProcessError as e:
             if not warn:
                 raise e
@@ -88,9 +92,13 @@ def ls(self):
 
     def uses(self, formula):
         args = ["--installed", "--recursive", formula]
-        return self.__spawn(
-            "uses", args, check_output=True
-        ).strip().split("\n")
+        return self.__spawn("uses", args,
+                            check_output=True).strip().split("\n")
+
+    def outdated(self):
+        output = self.__spawn("outdated", [],
+                              check_output=True).strip().split("\n")
+        return [_OUTDATED_RE.sub("", line) for line in output]
 
 
 class Defaults(object):

cider/core.py

@@ -218,6 +218,9 @@ def restore(self, ignore_errors=None):
         for tap in bootstrap.get("taps", []):
             homebrew.tap(tap)
 
+        outdated = homebrew.outdated()
+        outdated_casks = caskbrew.outdated()
+
         for formula in bootstrap.get("formulas", []):
             if formula in dependencies:
                 deps = dependencies[formula]
@@ -234,13 +237,14 @@ def restore(self, ignore_errors=None):
                         )
                     )
 
-                    caskbrew.safe_install(cask, ignore_errors)
+                    caskbrew.safe_install(cask, ignore_errors,
+                                          cask in outdated_casks)
                     del casks[casks.index(cask)]
 
-            homebrew.safe_install(formula, ignore_errors)
+            homebrew.safe_install(formula, ignore_errors, formula in outdated)
 
         for cask in casks:
-            caskbrew.safe_install(cask, ignore_errors)
+            caskbrew.safe_install(cask, ignore_errors, cask in outdated)
 
         self.relink()
         self.apply_defaults()