Make landmines work on local builds too

build/landmines.py

Index: build/landmines.py
diff --git a/build/landmines.py b/build/landmines.py
index 220b8a7989f45cd7a037473be6db65b70d2551b4..c31bac7901c362a320d735596dba887aa2d34ba3 100755
--- a/build/landmines.py
+++ b/build/landmines.py
@@ -4,10 +4,8 @@
 # found in the LICENSE file.
 
 """
-This script runs every build as a hook. If it detects that the build should
-be clobbered, it will touch the file <build_dir>/.landmine_triggered. The
-various build scripts will then check for the presence of this file and clobber
-accordingly. The script will also emit the reasons for the clobber to stdout.
+This script runs every build as the first hook (See DEPS). If it detects that
+the build should be clobbered, it will remove the build directory.
 
 A landmine is tripped when a builder checks out a different revision, and the
 diff between the new landmines and the old ones is non-null. At this point, the
@@ -16,9 +14,11 @@ build is clobbered.
 
 import difflib
 import errno
+import gyp_environment
 import logging
 import optparse
 import os
+import shutil
 import sys
 import subprocess
 import time
@@ -29,35 +29,32 @@ import landmine_utils
 SRC_DIR = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
 
 
-def get_target_build_dir(build_tool, target, is_iphone=False):
+def get_build_dir(build_tool, is_iphone=False):
   """
   Returns output directory absolute path dependent on build and targets.
   Examples:
-    r'c:\b\build\slave\win\build\src\out\Release'
-    '/mnt/data/b/build/slave/linux/build/src/out/Debug'
-    '/b/build/slave/ios_rel_device/build/src/xcodebuild/Release-iphoneos'
+    r'c:\b\build\slave\win\build\src\out'
+    '/mnt/data/b/build/slave/linux/build/src/out'
+    '/b/build/slave/ios_rel_device/build/src/xcodebuild'
 
   Keep this function in sync with tools/build/scripts/slave/compile.py
   """
   ret = None
   if build_tool == 'xcode':
-    ret = os.path.join(SRC_DIR, 'xcodebuild',
-        target + ('-iphoneos' if is_iphone else ''))
+    ret = os.path.join(SRC_DIR, 'xcodebuild')
   elif build_tool in ['make', 'ninja', 'ninja-ios']:  # TODO: Remove ninja-ios.
-    ret = os.path.join(SRC_DIR, 'out', target)
+    ret = os.path.join(SRC_DIR, 'out')
   elif build_tool in ['msvs', 'vs', 'ib']:
-    ret = os.path.join(SRC_DIR, 'build', target)
+    ret = os.path.join(SRC_DIR, 'build')
   else:
     raise NotImplementedError('Unexpected GYP_GENERATORS (%s)' % build_tool)
   return os.path.abspath(ret)
 
 
-def set_up_landmines(target, new_landmines):
+def clobber_if_necessary(new_landmines):
   """Does the work of setting, planting, and triggering landmines."""
-  out_dir = get_target_build_dir(landmine_utils.builder(), target,
-                                 landmine_utils.platform() == 'ios')
-
-  landmines_path = os.path.join(out_dir, '.landmines')
+  out_dir = get_build_dir(landmine_utils.builder())
+  landmines_path = os.path.normpath(os.path.join(out_dir, '..', '.landmines'))
   try:
     os.makedirs(out_dir)
   except OSError as e:
@@ -65,7 +62,6 @@ def set_up_landmines(target, new_landmines):
       pass
 
   if os.path.exists(landmines_path):
-    triggered = os.path.join(out_dir, '.landmines_triggered')
     with open(landmines_path, 'r') as f:
       old_landmines = f.readlines()
     if old_landmines != new_landmines:
@@ -73,12 +69,13 @@ def set_up_landmines(target, new_landmines):
       diff = difflib.unified_diff(old_landmines, new_landmines,
           fromfile='old_landmines', tofile='new_landmines',
           fromfiledate=old_date, tofiledate=time.ctime(), n=0)
+      sys.stdout.write('Clobbering due to:\n')
+      sys.stdout.writelines(diff)
+
+      # Clobber.
+      shutil.rmtree(out_dir)
 
-      with open(triggered, 'w') as f:
-        f.writelines(diff)
-    elif os.path.exists(triggered):
-      # Remove false triggered landmines.
-      os.remove(triggered)
+  # Save current set of landmines for next time.
   with open(landmines_path, 'w') as f:
     f.writelines(new_landmines)
 
@@ -119,14 +116,14 @@ def main():
   if landmine_utils.builder() in ('dump_dependency_json', 'eclipse'):
     return 0
 
-  for target in ('Debug', 'Release', 'Debug_x64', 'Release_x64'):
-    landmines = []
-    for s in landmine_scripts:
-      proc = subprocess.Popen([sys.executable, s, '-t', target],
-                              stdout=subprocess.PIPE)
-      output, _ = proc.communicate()
-      landmines.extend([('%s\n' % l.strip()) for l in output.splitlines()])
-    set_up_landmines(target, landmines)
+  gyp_environment.SetEnvironment()
+
+  landmines = []
+  for s in landmine_scripts:
+    proc = subprocess.Popen([sys.executable, s], stdout=subprocess.PIPE)
+    output, _ = proc.communicate()
+    landmines.extend([('%s\n' % l.strip()) for l in output.splitlines()])
+  clobber_if_necessary(landmines)
 
   return 0