总结：
1. git fetch scrapy
2. git merge scrapy/master
3. git push origin mastergithub上有个功能叫fork，可以将别人的工程复制到自己账号下。这个功能很方便，但其有一个缺点是：当源项目更新后，你fork的分支并不会一起更新，需要自己手动去更新。
以gitHub用户:lyt-python(组织名或者用户名)，fork 项目scrapy（https://github.com/scrapy/scrapy.git）为例子：
1、clone 自己账号里fork的分支
git clone https://github.com/lyt-python/scrapy.git
cd scrapy 2、增加远程原始分支到本地（可以用 git remote -v 命令查看远程分支列表）
$ git remote -v
origin https://github.com/lyt-python/scrapy.git (fetch)
origin https://github.com/lyt-python/scrapy.git (push) 如果没有远程原始分支则需要增加：
$ git remote add scrapy https://github.com/scrapy/scrapy.git 查看确认远程分支列表：
$ git remote -v
origin https://github.com/lyt-python/scrapy.git (fetch)
origin https://github.com/lyt-python/scrapy.git (push)
scrapy https://github.com/scrapy/scrapy.git (fetch)
scrapy https://github.com/scrapy/scrapy.git (push) 3、fetch原始源分支的新版本到本地
$ git fetch scrapy 会有如下信息：
remote: Counting objects: 2147, done.
remote: Compressing objects: 100% (11/11), done.
remote: Total 2147 (delta 1280), reused 1280 (delta 1280), pack-reused 856
Receiving objects: 100% (2147/2147), 490.60 KiB | 39.00 KiB/s, done.
Resolving deltas: 100% (1585/1585), completed with 204 local objects.
From https://github.com/scrapy/scrapy
* [new branch] 0.12 -> scrapy/0.12
* [new branch] 0.14 -> scrapy/0.14
* [new branch] 0.16 -> scrapy/0.16
* [new branch] 0.18 -> scrapy/0.18
* [new branch] 0.20 -> scrapy/0.20
* [new branch] 0.22 -> scrapy/0.22
* [new branch] 0.24 -> scrapy/0.24
* [new branch] 1.0 -> scrapy/1.0
* [new branch] 1.1 -> scrapy/1.1
* [new branch] asyncio -> scrapy/asyncio
* [new branch] deprecate-make-requests-from-url -> scrapy/deprecate-make-requests-from-url
* [new branch] disable-toplevel-2 -> scrapy/disable-toplevel-2
* [new branch] feature-1371-download-prios -> scrapy/feature-1371-download-prios
* [new branch] fix-1330 -> scrapy/fix-1330
* [new branch] fix-util-function-to-work-outside-project-dir -> scrapy/fix-util-function-to-work-outside-project-dir
* [new branch] master -> scrapy/master
* [new branch] no-max-rss -> scrapy/no-max-rss
* [new tag] 1.1.0rc3 -> 1.1.0rc3
* [new tag] 1.0.4 -> 1.0.4
* [new tag] 1.0.5 -> 1.0.5
* [new tag] 1.1.0rc1 -> 1.1.0rc1
* [new tag] 1.1.0rc2 -> 1.1.0rc2
* [new tag] 1.2.0dev2 -> 1.2.0dev2 4、合并两个版本的代码
$ git merge scrapy/master 会有如下信息：
Updating a5db7f8..ebef6d7
Fast-forward
.bumpversion.cfg | 2 +-
.travis.yml | 7 +-
CODE_OF_CONDUCT.md | 50 ++++
README.rst | 6 +
conftest.py | 2 +-
docs/contributing.rst | 4 +-
docs/faq.rst | 22 +-
docs/intro/install.rst | 8 +-
docs/intro/overview.rst | 6 +-
docs/intro/tutorial.rst | 8 +-
docs/news.rst | 242 ++++++++++++++++-
docs/topics/api.rst | 2 +-
docs/topics/architecture.rst | 6 +-
docs/topics/autothrottle.rst | 2 +
docs/topics/broad-crawls.rst | 2 +-
docs/topics/commands.rst | 4 +-
docs/topics/djangoitem.rst | 2 +-
docs/topics/downloader-middleware.rst | 40 ++-
docs/topics/email.rst | 11 +-
docs/topics/extensions.rst | 6 +-
docs/topics/feed-exports.rst | 15 +-
docs/topics/firebug.rst | 2 +-
docs/topics/item-pipeline.rst | 4 +-
docs/topics/media-pipeline.rst | 14 +-
docs/topics/practices.rst | 2 +-
docs/topics/request-response.rst | 53 ++--
docs/topics/selectors.rst | 10 +-
docs/topics/settings.rst | 164 ++++++++++--
docs/topics/shell.rst | 58 ++++-
docs/topics/signals.rst | 6 +-
docs/topics/spider-middleware.rst | 7 +-
docs/topics/spiders.rst | 4 +-
docs/topics/stats.rst | 8 +-
docs/topics/webservice.rst | 2 +-
docs/versioning.rst | 2 +-
requirements-py3.txt | 2 +-
scrapy/VERSION | 2 +-
scrapy/_monkeypatches.py | 4 +-
scrapy/cmdline.py | 9 +-
scrapy/commands/__init__.py | 2 -
scrapy/commands/fetch.py | 13 +-
scrapy/commands/settings.py | 9 +-
scrapy/commands/shell.py | 7 +-
scrapy/core/downloader/__init__.py | 2 +-
scrapy/core/downloader/contextfactory.py | 116 +++++++--
scrapy/core/downloader/handlers/http10.py | 5 +-
scrapy/core/downloader/handlers/http11.py | 119 +++++++--
scrapy/core/downloader/handlers/s3.py | 72 ++++--
scrapy/core/downloader/tls.py | 16 ++
scrapy/core/downloader/webclient.py | 41 ++-
scrapy/core/engine.py | 23 +-
scrapy/core/scheduler.py | 13 +-
scrapy/crawler.py | 17 +-
scrapy/downloadermiddlewares/ajaxcrawl.py | 2 +-
scrapy/downloadermiddlewares/httpcompression.py | 8 +-
scrapy/downloadermiddlewares/httpproxy.py | 15 +-
scrapy/downloadermiddlewares/retry.py | 2 +-
scrapy/downloadermiddlewares/robotstxt.py | 8 +-
scrapy/exporters.py | 77 ++++--
scrapy/extensions/closespider.py | 4 +
scrapy/extensions/feedexport.py | 37 ++-
scrapy/extensions/httpcache.py | 69 ++---
scrapy/extensions/spiderstate.py | 7 +-
scrapy/http/cookies.py | 22 +-
scrapy/http/headers.py | 10 +
scrapy/http/request/form.py | 14 +-
scrapy/http/response/text.py | 7 +-
scrapy/linkextractors/__init__.py | 3 +-
scrapy/mail.py | 7 +-
scrapy/middleware.py | 5 +-
scrapy/pipelines/files.py | 103 ++++++--
scrapy/responsetypes.py | 3 +-
scrapy/selector/unified.py | 2 +-
scrapy/settings/__init__.py | 29 ++-
scrapy/settings/default_settings.py | 11 +-
scrapy/spiderloader.py | 11 +-
scrapy/spiders/sitemap.py | 2 +-
scrapy/squeues.py | 4 +-
scrapy/templates/project/module/settings.py.tmpl | 3 +
scrapy/utils/benchserver.py | 12 +-
scrapy/utils/boto.py | 21 ++
scrapy/utils/datatypes.py | 25 +-
scrapy/utils/gz.py | 28 +-
scrapy/utils/iterators.py | 28 +-
scrapy/utils/misc.py | 4 +-
scrapy/utils/reactor.py | 2 +-
scrapy/utils/response.py | 4 +-
scrapy/utils/test.py | 35 ++-
scrapy/utils/testsite.py | 12 +-
scrapy/utils/url.py | 34 ++-
scrapy/xlib/lsprofcalltree.py | 120 ---------
scrapy/xlib/pydispatch.py | 19 ++
setup.cfg | 3 +
setup.py | 4 +
tests/mockserver.py | 89 ++++---
tests/py3-ignores.txt | 29 ---
tests/requirements-py3.txt | 2 +
tests/spiders.py | 2 +-
tests/test_cmdline/__init__.py | 2 +-
tests/test_command_fetch.py | 8 +-
tests/test_command_shell.py | 40 ++-
tests/test_commands.py | 71 +++--
tests/test_crawl.py | 9 +-
tests/test_downloader_handlers.py | 287 +++++++++++++++------
tests/test_downloadermiddleware.py | 7 +-
tests/test_downloadermiddleware_httpcache.py | 13 +-
tests/test_downloadermiddleware_httpcompression.py | 24 +-
tests/test_downloadermiddleware_httpproxy.py | 23 +-
tests/test_downloadermiddleware_retry.py | 8 +-
tests/test_downloadermiddleware_robotstxt.py | 12 +
tests/test_engine.py | 14 +-
tests/test_exporters.py | 206 +++++++++++----
tests/test_feedexport.py | 63 ++++-
tests/test_http_cookies.py | 4 +
tests/test_http_request.py | 20 ++
tests/test_http_response.py | 32 ++-
tests/test_mail.py | 54 +++-
tests/test_pipeline_files.py | 41 ++-
tests/test_pydispatch_deprecated.py | 12 +
tests/test_responsetypes.py | 11 +-
tests/test_settings/__init__.py | 23 +-
tests/test_spider.py | 12 +
tests/test_spidermiddleware_offsite.py | 9 +-
tests/test_spiderstate.py | 6 +
tests/test_utils_iterators.py | 83 +++++-
tests/test_utils_url.py | 65 ++++-
tests/test_webclient.py | 182 +++++++------
tox.ini | 10 +-
128 files changed, 2577 insertions(+), 967 deletions(-)
create mode 100644 CODE_OF_CONDUCT.md
create mode 100644 scrapy/core/downloader/tls.py
create mode 100644 scrapy/utils/boto.py
delete mode 100644 scrapy/xlib/lsprofcalltree.py
create mode 100644 scrapy/xlib/pydispatch.py
create mode 100644 tests/test_pydispatch_deprecated.py 5、把最新的代码提交到github自己（lyt-python）的账号上
$ git push origin master 会有如下信息：
Counting objects: 1802, done.
Delta compression using up to 24 threads.
Compressing objects: 100% (558/558), done.
Writing objects: 100% (1802/1802), 280.30 KiB | 0 bytes/s, done.
Total 1802 (delta 1395), reused 1644 (delta 1241)
To https://github.com/lyt-python/scrapy.git
a5db7f8..ebef6d7 master -> master