Make msys depot_tools upgrade process smoother.

bootstrap/win/win_tools.bat

 @echo off
 :: Copyright (c) 2012 The Chromium Authors. All rights reserved.
 :: Use of this source code is governed by a BSD-style license that can be
 :: found in the LICENSE file.
 
-:: This script will try to find if svn and python are accessible and it not,
-:: it will try to download it and 'install' it in depot_tools.
+:: This script will determine if python, git, or svn binaries need updates.  It
+:: returns 123 if the user's shell must restart, otherwise !0 is failure
 
 :: Sadly, we can't use SETLOCAL here otherwise it ERRORLEVEL is not correctly
 :: returned.
 
 set WIN_TOOLS_ROOT_URL=https://src.chromium.org/svn/trunk/tools
 :: It used to be %~dp0 but ADODB.Stream may fail to write to this directory if
 :: the directory DACL is set to elevated integrity level.
 set ZIP_DIR=%TEMP%
 
 :: Get absolute root directory (.js scripts don't handle relative paths well).
@@ skipping 58 matching lines @@
 set GIT_FETCH_URL=https://storage.googleapis.com/chrome-infra/PortableGit-%GIT_VERSION%-bit.7z.exe
 set GIT_DOWNLOAD_PATH=%ZIP_DIR%\git.7z.exe
 set GIT_BIN_DIR=git-%GIT_VERSION%_bin
 set GIT_INST_DIR=%WIN_TOOLS_ROOT_DIR%\%GIT_BIN_DIR%
 set GIT_EXE_PATH=%GIT_INST_DIR%\bin\git.exe
 
 :: Clean up any release which doesn't match the one we want.
 for /d %%i in ("%WIN_TOOLS_ROOT_DIR%\git-*_bin") do (
   if not "%%i" == "%WIN_TOOLS_ROOT_DIR%\git-%GIT_VERSION%_bin" (
     echo Cleaning old git installation %%i
-    rmdir /s /q "%%i"
+    rmdir /s /q "%%i" > NUL
   )
 )
 
 if "%WIN_TOOLS_FORCE%" == "1" goto :GIT_INSTALL
 
 if not exist "%GIT_EXE_PATH%" goto :GIT_INSTALL
 
 call "%GIT_EXE_PATH%" --version 2>nul 1>nul
 if errorlevel 1 goto :GIT_INSTALL
 
 :: Several git versions can live side-by-side; check the top-level
 :: batch script to make sure it points to the desired version.
 for %%f in (git.bat gitk.bat ssh.bat ssh-keygen.bat git-bash) do (
-  find "%GIT_BIN_DIR%" "%WIN_TOOLS_ROOT_DIR%\%%f" 2>nul 1>nul
+  %FIND_EXE% "%GIT_BIN_DIR%" "%WIN_TOOLS_ROOT_DIR%\%%f" 2>nul 1>nul
   if errorlevel 1 goto :GIT_MAKE_BATCH_FILES
 )
 goto :SYNC_GIT_HELP_FILES
 
 :GIT_INSTALL
 echo Installing git %GIT_VERSION% (avg 1-2 min download) ...
 
 if exist "%GIT_DOWNLOAD_PATH%" del "%GIT_DOWNLOAD_PATH%"
 echo Fetching from %GIT_FETCH_URL%
 cscript //nologo //e:jscript "%~dp0get_file.js" %GIT_FETCH_URL% "%GIT_DOWNLOAD_PATH%"
 if errorlevel 1 goto :GIT_FAIL
 :: Cleanup git directory if it already exists.
 if exist "%GIT_INST_DIR%\." rd /q /s "%GIT_INST_DIR%"
 
 :: run PortableGit self-extractor
 :: -y : Be Quiet ("yes")
 :: -sd1 : Self delete SFX archive
 :: -InstallPath : Where to put the files
 :: -Directory : Run the post-extract program with this current-working-directory
 ::
 :: Path slashes must be escaped or the 7zip sfx treats e.g. path\to\dir as
 ::   path[tab]o\dir.
 set GIT_INST_DIR_ESC=%GIT_INST_DIR:\=\\%
 call "%GIT_DOWNLOAD_PATH%" -y -sd1 -InstallPath="%GIT_INST_DIR_ESC%" -Directory="%GIT_INST_DIR_ESC%"
 if errorlevel 1 goto :GIT_FAIL
 
 del "%GIT_DOWNLOAD_PATH%"
 if not exist "%GIT_INST_DIR%\." goto :GIT_FAIL
 
+set DID_UPGRADE=1
+
 :GIT_MAKE_BATCH_FILES
 :: Create the batch files.
 set GIT_TEMPL=%~dp0git.template.bat
 set SED=%GIT_INST_DIR%\usr\bin\sed.exe
 call "%SED%" -e "s/GIT_BIN_DIR/%GIT_BIN_DIR%/g" -e "s/GIT_PROGRAM/cmd\\\\git.exe/g" < %GIT_TEMPL% > "%WIN_TOOLS_ROOT_DIR%\git.bat"
 call "%SED%" -e "s/GIT_BIN_DIR/%GIT_BIN_DIR%/g" -e "s/GIT_PROGRAM/cmd\\\\gitk.exe/g" < %GIT_TEMPL% > "%WIN_TOOLS_ROOT_DIR%\gitk.bat"
 call "%SED%" -e "s/GIT_BIN_DIR/%GIT_BIN_DIR%/g" -e "s/GIT_PROGRAM/usr\\\\bin\\\\ssh.exe/g" < %GIT_TEMPL% > "%WIN_TOOLS_ROOT_DIR%\ssh.bat"
 call "%SED%" -e "s/GIT_BIN_DIR/%GIT_BIN_DIR%/g" -e "s/GIT_PROGRAM/usr\\\\bin\\\\ssh-keygen.exe/g" < %GIT_TEMPL% > "%WIN_TOOLS_ROOT_DIR%\ssh-keygen.bat"
 call "%SED%" -e "s/GIT_BIN_DIR/%GIT_BIN_DIR%/g" -e "s/PYTHON_BIN_DIR/python276_bin/g" -e "s/SVN_BIN_DIR/svn_bin/g" < %~dp0git-bash.template.sh > "%WIN_TOOLS_ROOT_DIR%\git-bash"
 
 :: Ensure various git configurations are set correctly at they system level.
 call "%WIN_TOOLS_ROOT_DIR%\git.bat" config --system core.autocrlf false
 call "%WIN_TOOLS_ROOT_DIR%\git.bat" config --system core.filemode false
 call "%WIN_TOOLS_ROOT_DIR%\git.bat" config --system core.preloadindex true
 call "%WIN_TOOLS_ROOT_DIR%\git.bat" config --system core.fscache true
 
 :SYNC_GIT_HELP_FILES
 :: Copy all the depot_tools docs into the mingw64 git docs root.
 :: /i : Make sure xcopy knows that the destination names a folder, not a file
 :: /q : Make xcopy quiet (though it still prints a `X File(s) copied` message
 ::      which is why we have the > NUL)
 :: /d : Copy source files that are newer than the corresponding destination
 ::      files only. This prevents excessive copying when none of the docs
 ::      actually changed.
 :: /y : Don't prompt for overwrites (yes)
 xcopy /i /q /d /y "%WIN_TOOLS_ROOT_DIR%\man\html\*" "%GIT_INST_DIR%\mingw64\share\doc\git-doc" > NUL
 
+:: MSYS users need to restart their shell.
+if defined MSYSTEM if defined DID_UPGRADE (
+  echo.
+  echo.
+  echo IMPORTANT:
+  echo depot_tools' git distribution has been updated while inside of a MinGW
+  echo shell. In order to complete the upgrade, please exit the shell and re-run
+  echo `git bash` from cmd.
+  exit 123
+)
+
 goto :SVN_CHECK
 
 :GIT_FAIL
 echo ... Failed to checkout git automatically.
 echo You should get the "prebaked" version used at %GIT_FETCH_URL%
 set ERRORLEVEL=1
 goto :END
 
 
 :SVN_CHECK
@@ skipping 33 matching lines @@
 goto :END
 
 
 :returncode
 set WIN_TOOLS_ROOT_URL=
 set WIN_TOOLS_ROOT_DIR=
 exit /b %ERRORLEVEL%
 
 :END
 call :returncode %ERRORLEVEL%