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+# Contribution Guide
+
+<p>
+The CUE project welcomes all contributors.
+</p>
+
+<p>
+This document is a guide to help you through the process
+of contributing to the CUE project, which is a little different
+from that used by other open source projects.
+We assume you have a basic understanding of Git and Go.
+</p>
+
+<h2 id="contributor">Becoming a contributor</h2>
+
+<h3>Overview</h3>
+
+<p>
+The first step is registering as a CUE contributor and configuring your environment.
+Here is a checklist of the required steps to follow:
+</p>
+
+<ul>
+<li>
+<b>Step 0</b>: Decide on a single Google Account you will be using to contribute to CUE.
+Use that account for all the following steps and make sure that <code>git</code>
+is configured to create commits with that account's e-mail address.
+</li>
+<li>
+<b>Step 1</b>: <a href="https://cla.developers.google.com/clas">Sign and submit</a> a
+CLA (Contributor License Agreement).
+</li>
+<li>
+<b>Step 2</b>: Configure authentication credentials for the CUE Git repository.
+Visit <a href="https://cue.googlesource.com/">cue.googlesource.com</a>, click
+on "Generate Password" (top right), and follow the instructions.
+</li>
+<li>
+<b>Step 3</b>: Register for Gerrit, the code review tool used by the CUE team,
+by <a href="https://cue-review.googlesource.com/login/">visiting this page</a>.
+The CLA and the registration need to be done only once for your account.
+</li>
+<li>
+<b>Step 4</b>: Install <code>git-codereview</code> by running
+<code>go get -u golang.org/x/review/git-codereview</code>
+</li>
+</ul>
+
+<!-- TODO
+<p>
+If you prefer, there is an automated tool that walks through these steps.
+Just run:
+</p>
+
+<pre>
+$ go get -u cuelang.org/x/tools/cmd/cue-contrib-init
+$ cd /code/to/edit
+$ cue-contrib-init
+</pre>
+--->
+
+<p>
+The rest of this chapter elaborates on these instructions.
+If you have completed the steps above (either manually or through the tool), jump to
+<a href="#before_contributing">Before contributing code</a>.
+</p>
+
+<h3 id="google_account">Step 0: Select a Google Account</h3>
+
+<p>
+A contribution to CUE is made through a Google account with a specific
+e-mail address.
+Make sure to use the same account throughout the process and
+for all your subsequent contributions.
+You may need to decide whether to use a personal address or a corporate address.
+The choice will depend on who
+will own the copyright for the code that you will be writing
+and submitting.
+You might want to discuss this topic with your employer before deciding which
+account to use.
+</p>
+
+<p>
+Google accounts can either be Gmail e-mail accounts, G Suite organization accounts, or
+accounts associated with an external e-mail address.
+For instance, if you need to use
+an existing corporate e-mail that is not managed through G Suite, you can create
+an account associated
+<a href="https://accounts.google.com/SignUpWithoutGmail">with your existing
+e-mail address</a>.
+</p>
+
+<p>
+You also need to make sure that your Git tool is configured to create commits
+using your chosen e-mail address.
+You can either configure Git globally
+(as a default for all projects), or locally (for a single specific project).
+You can check the current configuration with this command:
+</p>
+
+<pre>
+$ git config --global user.email  # check current global config
+$ git config user.email           # check current local config
+</pre>
+
+<p>
+To change the configured address:
+</p>
+
+<pre>
+$ git config --global user.email name@example.com   # change global config
+$ git config user.email name@example.com            # change local config
+</pre>
+
+
+<h3 id="cla">Step 1: Contributor License Agreement</h3>
+
+<p>
+Before sending your first change to the CUE project
+you must have completed one of the following two CLAs.
+Which CLA you should sign depends on who owns the copyright to your work.
+</p>
+
+<ul>
+<li>
+If you are the copyright holder, you will need to agree to the
+<a href="https://developers.google.com/open-source/cla/individual">individual
+contributor license agreement</a>, which can be completed online.
+</li>
+<li>
+If your organization is the copyright holder, the organization
+will need to agree to the
+<a href="https://developers.google.com/open-source/cla/corporate">corporate
+contributor license agreement</a>.<br>
+</li>
+</ul>
+
+<p>
+You can check your currently signed agreements and sign new ones at
+the <a href="https://cla.developers.google.com/clas?pli=1&amp;authuser=1">Google Developers
+Contributor License Agreements</a> website.
+If the copyright holder for your contribution has already completed the
+agreement in connection with another Google open source project,
+it does not need to be completed again.
+</p>
+
+<p>
+If the copyright holder for the code you are submitting changes&mdash;for example,
+if you start contributing code on behalf of a new company&mdash;please send mail
+to the <a href="mailto:cue-dev@googlegroups.com"><code>cue-dev</code>
+mailing list</a>.
+This will let us know the situation so we can make sure an appropriate agreement is
+completed and update the <code>AUTHORS</code> file.
+</p>
+
+
+<h3 id="config_git_auth">Step 2: Configure git authentication</h3>
+
+<p>
+The main CUE repository is located at
+<a href="https://cue.googlesource.com">cue.googlesource.com</a>,
+a Git server hosted by Google.
+Authentication on the web server is made through your Google account, but
+you also need to configure <code>git</code> on your computer to access it.
+Follow this steps:
+</p>
+
+<ol>
+<li>
+Visit <a href="https://cue.googlesource.com">cue.googlesource.com</a>
+and click on "Generate Password" in the page's top right menu bar.
+You will be redirected to accounts.google.com to sign in.
+</li>
+<li>
+After signing in, you will be taken to a page with the title "Configure Git".
+This page contains a personalized script that when run locally will configure Git
+to hold your unique authentication key.
+This key is paired with one that is generated and stored on the server,
+analogous to how SSH keys work.
+</li>
+<li>
+Copy and run this script locally in your terminal to store your secret
+authentication token in a <code>.gitcookies</code> file.
+If you are using a Windows computer and running <code>cmd</code>,
+you should instead follow the instructions in the yellow box to run the command;
+otherwise run the regular script.
+</li>
+</ol>
+
+<h3 id="auth">Step 3: Create a Gerrit account </h3>
+
+<p>
+Gerrit is an open-source tool used by CUE maintainers to discuss and review
+code submissions.
+</p>
+
+<p>
+To register your account, visit <a href="https://cue-review.googlesource.com/login/">
+cue-review.googlesource.com/login/</a> and sign in once using the same Google Account you used above.
+</p>
+
+<h3 id="git-codereview_install">Step 4: Install the git-codereview command</h3>
+
+<p>
+Changes to CUE must be reviewed before they are accepted, no matter who makes the change.
+A custom <code>git</code> command called <code>git-codereview</code>
+simplifies sending changes to Gerrit.
+</p>
+
+<p>
+Install the <code>git-codereview</code> command by running,
+</p>
+
+<pre>
+$ go get -u golang.org/x/review/git-codereview
+</pre>
+
+<p>
+Make sure <code>git-codereview</code> is installed in your shell path, so that the
+<code>git</code> command can find it.
+Check that
+</p>
+
+<pre>
+$ git codereview help
+</pre>
+
+<p>
+prints help text, not an error.
+</p>
+
+<p>
+On Windows, when using git-bash you must make sure that
+<code>git-codereview.exe</code> is in your <code>git</code> exec-path.
+Run <code>git --exec-path</code> to discover the right location then create a
+symbolic link or just copy the executable from $GOPATH/bin to this directory.
+</p>
+
+
+<h2 id="before_contributing">Before contributing code</h2>
+
+<!--
+TODO
+<p>
+The project welcomes code patches, but to make sure things are well
+coordinated you should discuss any significant change before starting
+the work.
+It's recommended that you signal your intention to contribute in the
+issue tracker, either by <a href="https://cuelang.org/issue/new">filing
+a new issue</a> or by claiming
+an <a href="https://cuelang.org/issues">existing one</a>.
+</p>
+-->
+
+<h3>Check the issue tracker</h3>
+
+<p>
+Whether you already know what contribution to make, or you are searching for
+an idea, the <a href="https://github.com/cuelang/core/issues">issue tracker</a> is
+always the first place to go.
+Issues are triaged to categorize them and manage the workflow.
+</p>
+
+<p>
+Most issues will be marked with one of the following workflow labels:
+</p>
+
+<ul>
+	<li>
+	<b>NeedsInvestigation</b>: The issue is not fully understood
+	and requires analysis to understand the root cause.
+	</li>
+	<li>
+	<b>NeedsDecision</b>: the issue is relatively well understood, but the
+	CUE team hasn't yet decided the best way to address it.
+	It would be better to wait for a decision before writing code.
+	If you are interested on working on an issue in this state,
+	feel free to "ping" maintainers in the issue's comments
+	if some time has passed without a decision.
+	</li>
+	<li>
+	<b>NeedsFix</b>: the issue is fully understood and code can be written
+	to fix it.
+	</li>
+</ul>
+
+<p>
+You can use GitHub's search functionality to find issues to help out with. Examples:
+</p>
+
+<ul>
+	<li>
+	Issues that need investigation: <a href="https://github.com/cuelang/core/issues?q=is%3Aissue+is%3Aopen+label%3ANeedsInvestigation"><code>is:issue is:open label:NeedsInvestigation</code></a>
+	</li>
+	<li>
+	Issues that need a fix: <a href="https://github.com/cuelang/core/issues?q=is%3Aissue+is%3Aopen+label%3ANeedsFix"><code>is:issue is:open label:NeedsFix</code></a>
+	</li>
+	<li>
+	Issues that need a fix and have a CL: <a href="https://github.com/cuelang/core/issues?q=is%3Aissue+is%3Aopen+label%3ANeedsFix+%22golang.org%2Fcl%22"><code>is:issue is:open label:NeedsFix "cuelang.org/cl"</code></a>
+	</li>
+	<li>
+	Issues that need a fix and do not have a CL: <a href="https://github.com/cuelang/core/issues?q=is%3Aissue+is%3Aopen+label%3ANeedsFix+NOT+%22golang.org%2Fcl%22"><code>is:issue is:open label:NeedsFix NOT "cuelang.org/cl"</code></a>
+	</li>
+</ul>
+
+<h3 id="design">Open an issue for any new problem</h3>
+
+<p>
+Excluding very trivial changes, all contributions should be connected
+to an existing issue.
+Feel free to open one and discuss your plans.
+This process gives everyone a chance to validate the design,
+helps prevent duplication of effort,
+and ensures that the idea fits inside the goals for the language and tools.
+It also checks that the design is sound before code is written;
+the code review tool is not the place for high-level discussions.
+</p>
+
+<!--
+TODO
+<p>
+When planning work, please note that the CUE project follows a <a
+href="https://cuelang.org/wiki/CUE-Release-Cycle">six-month development cycle</a>.
+The latter half of each cycle is a three-month feature freeze during
+which only bug fixes and documentation updates are accepted.
+New contributions can be sent during a feature freeze, but they will
+not be merged until the freeze is over.
+</p>
+
+<p>
+Significant changes to the language, libraries, or tools must go
+through the
+<a href="https://cuelang.org/s/proposal-process">change proposal process</a>
+before they can be accepted.
+</p>
+
+<p>
+Sensitive security-related issues (only!) should be reported to <a href="mailto:security@cuelang.org">security@cuelang.org</a>.
+</p>
+
+<h2 id="sending_a_change_github">Sending a change via GitHub</h2>
+
+<p>
+First-time contributors that are already familiar with the
+<a href="https://guides.github.com/introduction/flow/">GitHub flow</a>
+are encouraged to use the same process for CUE contributions.
+Even though CUE
+maintainers use Gerrit for code review, a bot called Gopherbot has been created to sync
+GitHub pull requests to Gerrit.
+</p>
+
+<p>
+Open a pull request as you normally would.
+Gopherbot will create a corresponding Gerrit change and post a link to
+it on your GitHub pull request; updates to the pull request will also
+get reflected in the Gerrit change.
+When somebody comments on the change, their comment will be also
+posted in your pull request, so you will get a notification.
+</p>
+
+<p>
+Some things to keep in mind:
+</p>
+
+<ul>
+<li>
+To update the pull request with new code, just push it to the branch; you can either
+add more commits, or rebase and force-push (both styles are accepted).
+</li>
+<li>
+If the request is accepted, all commits will be squashed, and the final
+commit description will be composed by concatenating the pull request's
+title and description.
+The individual commits' descriptions will be discarded.
+See <a href="#commit_messages">Writing good commit messages</a> for some
+suggestions.
+</li>
+<li>
+Gopherbot is unable to sync line-by-line codereview into GitHub: only the
+contents of the overall comment on the request will be synced.
+Remember you can always visit Gerrit to see the fine-grained review.
+</li>
+</ul>
+-->
+
+<h2 id="sending_a_change_gerrit">Sending a change via Gerrit</h2>
+
+<p>
+It is not possible to fully sync Gerrit and GitHub, at least at the moment,
+so we recommend learning Gerrit.
+It's different but powerful and familiarity
+with help you understand the flow.
+</p>
+
+<h3>Overview</h3>
+
+<p>
+This is an overview of the overall process:
+</p>
+
+<ul>
+<li>
+<b>Step 1:</b> Clone the CUE source code from cue.googlesource.com
+and make sure it's stable by compiling and testing it once:
+<pre>
+$ git clone https://cue.googlesource.com/core
+$ cd core
+$ go test ./...
+$ go install ./cmd/cue
+</pre>
+</li>
+
+<li>
+<b>Step 2:</b> Prepare changes in a new branch, created from the master branch.
+To commit the changes, use <code>git</code> <code>codereview</code> <code>change</code>; that
+will create or amend a single commit in the branch.
+<pre>
+$ git checkout -b mybranch
+$ [edit files...]
+$ git add [files...]
+$ git codereview change   # create commit in the branch
+$ [edit again...]
+$ git add [files...]
+$ git codereview change   # amend the existing commit with new changes
+$ [etc.]
+</pre>
+</li>
+
+<li>
+<b>Step 3:</b> Test your changes, re-running <code>go test</code>.
+<pre>
+$ go test ./...    # recompile and test
+</pre>
+</li>
+
+<li>
+<b>Step 4:</b> Send the changes for review to Gerrit using <code>git</code>
+<code>codereview</code> <code>mail</code> (which doesn't use e-mail, despite the name).
+<pre>
+$ git codereview mail     # send changes to Gerrit
+</pre>
+</li>
+
+<li>
+<b>Step 5:</b> After a review, apply changes to the same single commit
+and mail them to Gerrit again:
+<pre>
+$ [edit files...]
+$ git add [files...]
+$ git codereview change   # update same commit
+$ git codereview mail     # send to Gerrit again
+</pre>
+</li>
+</ul>
+
+<p>
+The rest of this section describes these steps in more detail.
+</p>
+
+
+<h3 id="checkout_go">Step 1: Clone the CUE source code</h3>
+
+<p>
+In addition to a recent CUE installation, you need to have a local copy of the source
+checked out from the correct repository.
+You can check out the CUE source repo onto your local file system anywhere
+you want as long as it's outside your <code>GOPATH</code>.
+Either clone from
+<code>cue.googlesource.com</code> or from GitHub:
+</p>
+
+<pre>
+$ git clone https://github.com/cuelang/core   # or https://cue.googlesource.com/core
+$ cd core
+$ go test ./...
+# go install ./cmd/cue
+</pre>
+
+<h3 id="make_branch">Step 2: Prepare changes in a new branch</h3>
+
+<p>
+Each CUE change must be made in a separate branch, created from the master branch.
+You can use
+the normal <code>git</code> commands to create a branch and add changes to the
+staging area:
+</p>
+
+<pre>
+$ git checkout -b mybranch
+$ [edit files...]
+$ git add [files...]
+</pre>
+
+<p>
+To commit changes, instead of <code>git commit</code>, use <code>git codereview change</code>.
+</p>
+
+<pre>
+$ git codereview change
+(open $EDITOR)
+</pre>
+
+<p>
+You can edit the commit description in your favorite editor as usual.
+The  <code>git</code> <code>codereview</code> <code>change</code> command
+will automatically add a unique Change-Id line near the bottom.
+That line is used by Gerrit to match successive uploads of the same change.
+Do not edit or delete it.
+A Change-Id looks like this:
+</p>
+
+<pre>
+Change-Id: I2fbdbffb3aab626c4b6f56348861b7909e3e8990
+</pre>
+
+<p>
+The tool also checks that you've
+run <code>go</code> <code>fmt</code> over the source code, and that
+the commit message follows the <a href="#commit_messages">suggested format</a>.
+</p>
+
+<p>
+If you need to edit the files again, you can stage the new changes and
+re-run <code>git</code> <code>codereview</code> <code>change</code>: each subsequent
+run will amend the existing commit while preserving the Change-Id.
+</p>
+
+<p>
+Make sure that you always keep a single commit in each branch.
+If you add more
+commits by mistake, you can use <code>git</code> <code>rebase</code> to
+<a href="https://stackoverflow.com/questions/31668794/squash-all-your-commits-in-one-before-a-pull-request-in-github">squash them together</a>
+into a single one.
+</p>
+
+
+<h3 id="testing">Step 3: Test your changes</h3>
+
+<p>
+You've <a href="code.html">written and tested your code</a>, but
+before sending code out for review, run <i>all the tests for the whole
+tree</i> to make sure the changes don't break other packages or programs:
+</p>
+
+<pre>
+$ go test ./...
+</pre>
+
+
+<h3 id="mail">Step 4: Send changes for review</h3>
+
+<p>
+Once the change is ready and tested over the whole tree, send it for review.
+This is done with the <code>mail</code> sub-command which, despite its name, doesn't
+directly mail anything; it just sends the change to Gerrit:
+</p>
+
+<pre>
+$ git codereview mail
+</pre>
+
+<p>
+Gerrit assigns your change a number and URL, which <code>git</code> <code>codereview</code> <code>mail</code> will print, something like:
+</p>
+
+<pre>
+remote: New Changes:
+remote:   https://cue-review.googlesource.com/99999 math: improved Sin, Cos and Tan precision for very large arguments
+</pre>
+
+<p>
+If you get an error instead, check the
+<a href="#troubleshooting_mail">Troubleshooting mail errors</a> section.
+</p>
+
+<p>
+If your change relates to an open GitHub issue and you have followed the <a href="#commit_messages">
+suggested commit message format</a>, the issue will be updated in a few minutes by a bot,
+linking your Gerrit change to it in the comments.
+</p>
+
+
+<h3 id="revise">Step 5: Revise changes after a review</h3>
+
+<p>
+CUE maintainers will review your code on Gerrit, and you will get notifications via e-mail.
+You can see the review on Gerrit and comment on them there.
+You can also reply
+<a href="https://gerrit-review.googlesource.com/Documentation/intro-user.html#reply-by-email">using e-mail</a>
+if you prefer.
+</p>
+
+<p>
+If you need to revise your change after the review, edit the files in
+the same branch you previously created, add them to the Git staging
+area, and then amend the commit with
+<code>git</code> <code>codereview</code> <code>change</code>:
+</p>
+
+<pre>
+$ git codereview change     # amend current commit
+(open $EDITOR)
+$ git codereview mail       # send new changes to Gerrit
+</pre>
+
+<p>
+If you don't need to change the commit description, just save and exit from the editor.
+Remember not to touch the special Change-Id line.
+</p>
+
+<p>
+Again, make sure that you always keep a single commit in each branch.
+If you add more
+commits by mistake, you can use <code>git rebase</code> to
+<a href="https://stackoverflow.com/questions/31668794/squash-all-your-commits-in-one-before-a-pull-request-in-github">squash them together</a>
+into a single one.
+</p>
+
+<h2 id="commit_messages">Good commit messages</h2>
+
+<p>
+Commit messages in CUE follow a specific set of conventions,
+which we discuss in this section.
+</p>
+
+<p>
+Here is an example of a good one:
+</p>
+
+<pre>
+math: improve Sin, Cos and Tan precision for very large arguments
+
+The existing implementation has poor numerical properties for
+large arguments, so use the McGillicutty algorithm to improve
+accuracy above 1e10.
+
+The algorithm is described at https://wikipedia.org/wiki/McGillicutty_Algorithm
+
+Fixes #159
+</pre>
+
+<h3>First line</h3>
+
+<p>
+The first line of the change description is conventionally a short one-line
+summary of the change, prefixed by the primary affected package.
+</p>
+
+<p>
+A rule of thumb is that it should be written so to complete the sentence
+"This change modifies CUE to _____."
+That means it does not start with a capital letter, is not a complete sentence,
+and actually summarizes the result of the change.
+</p>
+
+<p>
+Follow the first line by a blank line.
+</p>
+
+<h3>Main content</h3>
+
+<p>
+The rest of the description elaborates and should provide context for the
+change and explain what it does.
+Write in complete sentences with correct punctuation, just like
+for your comments in CUE.
+Don't use HTML, Markdown, or any other markup language.
+</p>
+
+
+<h3>Referencing issues</h3>
+
+<p>
+The special notation "Fixes #12345" associates the change with issue 12345 in the
+<a href="https://cuelang.org/issue/12345">CUE issue tracker</a>.
+When this change is eventually applied, the issue
+tracker will automatically mark the issue as fixed.
+</p>
+
+<p>
+If the change is a partial step towards the resolution of the issue,
+uses the notation "Updates #12345".
+This will leave a comment in the issue
+linking back to the change in Gerrit, but it will not close the issue
+when the change is applied.
+</p>
+
+<p>
+If you are sending a change against a subrepository, you must use
+the fully-qualified syntax supported by GitHub to make sure the change is
+linked to the issue in the main repository, not the subrepository.
+All issues are tracked in the main repository's issue tracker.
+The correct form is "Fixes cuelang/core#159".
+</p>
+
+
+<h2 id="review">The review process</h2>
+
+<p>
+This section explains the review process in detail and how to approach
+reviews after a change has been mailed.
+</p>
+
+
+<h3 id="mistakes">Common beginner mistakes</h3>
+
+<p>
+When a change is sent to Gerrit, it is usually triaged within a few days.
+A maintainer will have a look and provide some initial review that for first-time
+contributors usually focuses on basic cosmetics and common mistakes.
+These include things like:
+</p>
+
+<ul>
+<li>
+Commit message not following the <a href="#commit_messages">suggested
+format</a>.
+</li>
+
+<li>
+The lack of a linked GitHub issue.
+The vast majority of changes
+require a linked issue that describes the bug or the feature that the change
+fixes or implements, and consensus should have been reached on the tracker
+before proceeding with it.
+Gerrit reviews do not discuss the merit of the change,
+just its implementation.
+<br>
+Only trivial or cosmetic changes will be accepted without an associated issue.
+</li>
+
+<li>
+Change sent during the freeze phase of the development cycle, when the tree
+is closed for general changes.
+In this case,
+a maintainer might review the code with a line such as <code>R=go1.12</code>,
+which means that it will be reviewed later when the tree opens for a new
+development window.
+You can add <code>R=go1.XX</code> as a comment yourself
+if you know that it's not the correct time frame for the change.
+</li>
+</ul>
+
+<!--
+TODO
+<h3 id="trybots">Trybots</h3>
+
+<p>
+After an initial reading of your change, maintainers will trigger trybots,
+a cluster of servers that will run the full test suite on several different
+architectures.
+Most trybots complete in a few minutes, at which point a link will
+be posted in Gerrit where you can see the results.
+</p>
+
+<p>
+If the trybot run fails, follow the link and check the full logs of the
+platforms on which the tests failed.
+Try to understand what broke, update your patch to fix it, and upload again.
+Maintainers will trigger a new trybot run to see
+if the problem was fixed.
+</p>
+
+<p>
+Sometimes, the tree can be broken on some platforms for a few hours; if
+the failure reported by the trybot doesn't seem related to your patch, go to the
+<a href="https://build.cuelang.org">Build Dashboard</a> and check if the same
+failure appears in other recent commits on the same platform.
+In this case,
+feel free to write a comment in Gerrit to mention that the failure is
+unrelated to your change, to help maintainers understand the situation.
+</p>
+-->
+
+<h3 id="reviews">Reviews</h3>
+
+<p>
+The CUE community values very thorough reviews.
+Think of each review comment like a ticket: you are expected to somehow "close" it
+by acting on it, either by implementing the suggestion or convincing the
+reviewer otherwise.
+</p>
+
+<p>
+After you update the change, go through the review comments and make sure
+to reply to every one.
+You can click the "Done" button to reply
+indicating that you've implemented the reviewer's suggestion; otherwise,
+click on "Reply" and explain why you have not, or what you have done instead.
+</p>
+
+<p>
+It is perfectly normal for changes to go through several round of reviews,
+with one or more reviewers making new comments every time
+and then waiting for an updated change before reviewing again.
+This cycle happens even for experienced contributors, so
+don't be discouraged by it.
+</p>
+
+<h3 id="votes">Voting conventions</h3>
+
+<p>
+As they near a decision, reviewers will make a "vote" on your change.
+The Gerrit voting system involves an integer in the range -2 to +2:
+</p>
+
+<ul>
+	<li>
+	<b>+2</b> The change is approved for being merged.
+	Only CUE maintainers can cast a +2 vote.
+	</li>
+	<li>
+	<b>+1</b> The change looks good, but either the reviewer is requesting
+	minor changes before approving it, or they are not a maintainer and cannot
+	approve it, but would like to encourage an approval.
+	</li>
+	<li>
+	<b>-1</b> The change is not good the way it is but might be fixable.
+	A -1 vote will always have a comment explaining why the change is unacceptable.
+	</li>
+	<li>
+	<b>-2</b> The change is blocked by a maintainer and cannot be approved.
+	Again, there will be a comment explaining the decision.
+	</li>
+</ul>
+
+<h3 id="submit">Submitting an approved change</h3>
+
+<p>
+After the code has been +2'ed, an approver will
+apply it to the master branch using the Gerrit user interface.
+This is called "submitting the change".
+</p>
+
+<p>
+The two steps (approving and submitting) are separate because in some cases maintainers
+may want to approve it but not to submit it right away (for instance,
+the tree could be temporarily frozen).
+</p>
+
+<p>
+Submitting a change checks it into the repository.
+The change description will include a link to the code review,
+which will be updated with a link to the change
+in the repository.
+Since the method used to integrate the changes is Git's "Cherry Pick",
+the commit hashes in the repository will be changed by
+the submit operation.
+</p>
+
+<p>
+If your change has been approved for a few days without being
+submitted, feel free to write a comment in Gerrit requesting
+submission.
+</p>
+
+
+<!--
+
+<h3 id="more_information">More information</h3>
+
+TODO
+<p>
+In addition to the information here, the CUE community maintains a <a
+href="https://cuelang.org/wiki/CodeReview">CodeReview</a> wiki page.
+Feel free to contribute to this page as you learn more about the review process.
+</p>
+-->
+
+
+<h2 id="advanced_topics">Miscellaneous topics</h2>
+
+<p>
+This section collects a number of other comments that are
+outside the issue/edit/code review/submit process itself.
+</p>
+
+
+<h3 id="copyright">Copyright headers</h3>
+
+<p>
+Files in the CUE repository don't list author names, both to avoid clutter
+and to avoid having to keep the lists up to date.
+Instead, your name will appear in the
+<a href="https://cue.googlesource.com/core/+log">change log</a> and in the <a
+href="/CONTRIBUTORS"><code>CONTRIBUTORS</code></a> file and perhaps the <a
+href="/AUTHORS"><code>AUTHORS</code></a> file.
+These files are automatically generated from the commit logs periodically.
+The <a href="/AUTHORS"><code>AUTHORS</code></a> file defines who &ldquo;The CUE
+Authors&rdquo;&mdash;the copyright holders&mdash;are.
+</p>
+
+<p>
+New files that you contribute should use the standard copyright header:
+</p>
+
+<pre>
+// Copyright 2018 The CUE Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+</pre>
+
+<p>
+(Use the current year if you're reading this in 2019 or beyond.)
+Files in the repository are copyrighted the year they are added.
+Do not update the copyright year on files that you change.
+</p>
+
+
+
+
+<h3 id="troubleshooting_mail">Troubleshooting mail errors</h3>
+
+<p>
+The most common way that the <code>git</code> <code>codereview</code> <code>mail</code>
+command fails is because the e-mail address in the commit does not match the one
+that you used during <a href="#google_account">the registration process</a>.
+
+<br>
+If you see something like...
+</p>
+
+<pre>
+remote: Processing changes: refs: 1, done
+remote:
+remote: ERROR:  In commit ab13517fa29487dcf8b0d48916c51639426c5ee9
+remote: ERROR:  author email address XXXXXXXXXXXXXXXXXXX
+remote: ERROR:  does not match your user account.
+</pre>
+
+<p>
+you need to configure Git for this repository to use the
+e-mail address that you registered with.
+To change the e-mail address to ensure this doesn't happen again, run:
+</p>
+
+<pre>
+$ git config user.email email@address.com
+</pre>
+
+<p>
+Then change the commit to use this alternative e-mail address with this command:
+</p>
+
+<pre>
+$ git commit --amend --author="Author Name &lt;email@address.com&gt;"
+</pre>
+
+<p>
+Then retry by running:
+</p>
+
+<pre>
+$ git codereview mail
+</pre>
+
+
+<h3 id="quick_test">Quickly testing your changes</h3>
+
+<p>
+Running <code>go test ./...</code> for every single change to the code tree
+is burdensome.
+Even though it is strongly suggested to run it before
+sending a change, during the normal development cycle you may want
+to compile and test only the package you are developing.
+</p>
+
+<li>
+In this section, we'll call the directory into which you cloned the CUE repository <code>$CUEDIR</code>.
+As CUE uses Go modules, The <code>cue</code> tool built by
+<code>go install</code> will be installed in the <code>bin/go</code> in your
+home directory by default.
+</li>
+
+<li>
+If you're changing the CUE APIs or code, you can test the results in just
+this package directory.
+
+<pre>
+$ cd $CUEDIR/cue
+$ [make changes...]
+$ go test
+</pre>
+
+You don't need to build a new cue tool to test it.
+Instead you can run the tests from the root.
+
+<pre>
+$ cd $CUEDIR
+$ go test ./...
+</pre>
+
+To use the new tool you would still need to build and install it.
+</li>
+
+
+<!--
+TODO
+<h3 id="subrepos">Contributing to subrepositories (cuelang.org/x/...)</h3>
+
+<p>
+If you are contributing a change to a subrepository, obtain the
+CUE package using <code>go get</code>.
+For example, to contribute
+to <code>cuelang.org/x/editor/vscode</code>, check out the code by running:
+</p>
+
+<pre>
+$ go get -d cuelang.org/editor/vscode
+</pre>
+
+<p>
+Then, change your directory to the package's source directory
+(<code>$GOPATH/src/cuelang.org/x/oauth2</code>), and follow the
+normal contribution flow.
+</p>
+-->
+
+<h3 id="cc">Specifying a reviewer / CCing others</h3>
+
+<!--
+TODO:
+
+<p>
+Unless explicitly told otherwise, such as in the discussion leading
+up to sending in the change, it's better not to specify a reviewer.
+All changes are automatically CC'ed to the
+<a href="https://groups.google.com/group/cue-codereviews">cue-codereviews@googlegroups.com</a>
+mailing list.
+If this is your first ever change, there may be a moderation
+delay before it appears on the mailing list, to prevent spam.
+</p>
+-->
+
+<p>
+You can specify a reviewer or CC interested parties
+using the <code>-r</code> or <code>-cc</code> options.
+Both accept a comma-separated list of e-mail addresses:
+</p>
+
+<pre>
+$ git codereview mail -r joe@cuelang.org -cc mabel@example.com,math-nuts@swtch.com
+</pre>
+
+
+<h3 id="sync">Synchronize your client</h3>
+
+<p>
+While you were working, others might have submitted changes to the repository.
+To update your local branch, run
+</p>
+
+<pre>
+$ git codereview sync
+</pre>
+
+<p>
+(Under the covers this runs
+<code>git</code> <code>pull</code> <code>-r</code>.)
+</p>
+
+
+<h3 id="download">Reviewing code by others</h3>
+
+<p>
+As part of the review process reviewers can propose changes directly (in the
+GitHub workflow this would be someone else attaching commits to a pull request).
+
+You can import these changes proposed by someone else into your local Git repository.
+On the Gerrit review page, click the "Download ▼" link in the upper right
+corner, copy the "Checkout" command and run it from your local Git repo.
+It will look something like this:
+</p>
+
+<pre>
+$ git fetch https://cue.googlesource.com/review refs/changes/21/13245/1 &amp;&amp; git checkout FETCH_HEAD
+</pre>
+
+<p>
+To revert, change back to the branch you were working in.
+</p>
+
+
+<h3 id="git-config">Set up git aliases</h3>
+
+<p>
+The <code>git-codereview</code> command can be run directly from the shell
+by typing, for instance,
+</p>
+
+<pre>
+$ git codereview sync
+</pre>
+
+<p>
+but it is more convenient to set up aliases for <code>git-codereview</code>'s own
+subcommands, so that the above becomes,
+</p>
+
+<pre>
+$ git sync
+</pre>
+
+<p>
+The <code>git-codereview</code> subcommands have been chosen to be distinct from
+Git's own, so it's safe to define these aliases.
+To install them, copy this text into your
+Git configuration file (usually <code>.gitconfig</code> in your home directory):
+</p>
+
+<pre>
+[alias]
+	change = codereview change
+	gofmt = codereview gofmt
+	mail = codereview mail
+	pending = codereview pending
+	submit = codereview submit
+	sync = codereview sync
+</pre>
+
+
+<h3 id="multiple_changes">Sending multiple dependent changes</h3>
+
+<p>
+Advanced users may want to stack up related commits in a single branch.
+Gerrit allows for changes to be dependent on each other, forming such a dependency chain.
+Each change will need to be approved and submitted separately but the dependency
+will be visible to reviewers.
+</p>
+
+<p>
+To send out a group of dependent changes, keep each change as a different commit under
+the same branch, and then run:
+</p>
+
+<pre>
+$ git codereview mail HEAD
+</pre>
+
+<p>
+Make sure to explicitly specify <code>HEAD</code>, which is usually not required when sending
+single changes.
+</p>