Visual Studio Code Dev

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Visual Studio Code (VS Code) is a free, open source, lightweight and powerful code editor for Windows, macOS and Linux, based on Electron/Chromium. It has built-in support for JavaScript, TypeScript and Node.js and a rich extension ecosystem that adds intellisense, debugging, syntax highlighting etc. For many languages like C++, Python, Go, Java, it works without too much setup.

It is NOT a full-fledged IDE like Visual Studio. The two are completely separate products. The only commonality with Visual Studio is that both are from Microsoft.

Here's what works well:

Editing code works well especially when you get used to the keyboard shortcuts. VS Code is very responsive and can handle even big code bases like Chromium.
Git integration is a blast. Built-in side-by-side view, local commit and even extensions for history and blame view.
Debugging works well, even though startup times can be fairly high (~40 seconds with gdb on Linux, much lower on Windows). You can step through code, inspect variables, view call stacks for multiple threads etc.
- For more information on debugging Python code, see here.
Command Palette makes opening files and searching solution really easy.
Building works well. Build tools are easy to integrate. Warnings and errors are displayed on a separate page and you can click to jump to the corresponding line of code.
VS Code Remote, which allows you to edit remotely-hosted code, and even run computationally expensive plugins like vscode-clangd on the remote server. Great for working from home. See the Remote section for more details.

[TOC]

Updating This Page

Please keep this doc up-to-date. VS Code is still in active development and subject to changes. This doc is checked into the Chromium git repo, so if you make changes, read the documentation guidelines and submit a change list.

All file paths and commands have been tested on Linux and macOS. Windows might require a slightly different setup. Please update this page accordingly.

Setup

Installation

*** promo Googlers: See go/vscode/install instead.

Follow the steps on Setting up Visual Studio Code to install a proper version for you development platform.

Usage

To run it on Linux or on macOS:

cd /path/to/chromium/src
code .

If you installed Code Insiders, the binary name is code-insiders instead.

Note that VS Code does not require project or solution files. However, it does store workspace settings in a .vscode folder in your base directory (i.e. your project root folder). See the Chromium Workspace Settings section for details.

Useful Extensions

Up to now, you have a basic version of VS Code without much language support. Next, we will install some useful extensions.

Recommended Extensions

You will most likely use the following extensions every day:

There are 2 ways to install them:

Follow the instructions from Install Recommended Extensions.
Manual installation. Jump to the extensions window (Ctrl+Shift+X, or Cmd+Shift+X in macOS) and search the names of the following extensions.

*** aside Note: All the extension settings mentioned below are already set in tools/vscode/settings.json. You don't have do anything if you have followed the instructions to copy that file into your workspace.

ChromiumIDE - The critical extension to make Chromium/ChromiumOS development easier and faster by anchoring core tools in one place.
Chromium Context - Provides Chromium-specific context, e.g. code owners, release version, author blame list, in a single tab for an opened file.
C/C++ - Code formatting, debugging, Intellisense. Enables the use of clang-format (via the C_Cpp.clang_format_path setting) and format-on-save (via the editor.formatOnSave setting).
vscode-clangd - Enables VS Code to compile Chromium, provide Chromium XRefs to support functions like jumping to definition, and provide a clangd language server powering smarter autocompletion than C/C++ extension's IntelliSense, but they also conflicts with each other. To resolve the conflict, add the following to settings.json: "C_Cpp.intelliSenseEngine": "disabled". See clangd.md for setup instructions.
Toggle Header/Source - Toggles between .cc and .h with F4. The C/C++ extension supports this as well through Alt+O but sometimes chooses the wrong file when there are multiple files in the workspace that have the same name.
vscode-proto3 - Syntax highlighting for .proto files.
Mojom IDL support - Syntax highlighting and a language server for .mojom files.
GN - Code IntelliSense for the GN build system.
Rewrap - Wrap lines at 80 characters with Alt+Q.
Remote - Remotely connect to your workstation through SSH using your laptop. See the Remote section for more information about how to set this up.
GitLens - Git supercharged. A Powerful, feature rich, and highly customizable git extension.
Python - Linting, intellisense, code formatting, refactoring, debugging, snippets.
- If you want type checking, add: "python.analysis.typeCheckingMode": "basic", to your settings.json file (you can also find it in the settings UI).

Optional Extensions

The following extensions are not included in //tools/vscode/settings.json, but they might be useful for you as well:

$ echo "ryu1kn.annotator wmaurer.change-case shd101wyy.markdown-preview-enhanced Gruntfuggly.todo-tree alefragnani.Bookmarks spmeesseman.vscode-taskexplorer streetsidesoftware.code-spell-checker george-alisson.html-preview-vscode anseki.vscode-color" | xargs -n 1 code --force --install-extension

Annotator - Display git blame info along with your code. Can open the diff of a particular commit from there.
change-case - Quickly change the case of the current selection or current word.
Markdown Preview Enhanced - Preview markdown side-by-side with automatic scroll sync and many other features with Ctrl+k v. This document was written with this extension!
Todo Tree - Displays comment tags like TODO/FIXME in a tree view in a dedicated sidebar.
Bookmarks - Supports easy mark/unmark positions in the codebase and displays them in a dedicated sidebar. Very useful for a large codebase like Chromium.
Task Explorer - Displays supported tasks, e.g. vscode tasks, shell scripts and others, organized into a treeview in sidebar.
Code Spell Checker - A basic spell checker that works well with camelCase code. It helps catch common spelling errors.
HTML Preview - Previews HTML files while editing with Ctrl+k v.
Color Picker - Visualizes color codes inline and provides color picker GUI to generates new color codes.
Bazel - This is very useful for editing *.star starlark files. If you want "Go to definition" to work in our infra/config directory, see the //tools/vscode/bazel_lsp/README.md

Also be sure to take a look at the VS Code marketplace to check out other useful extensions.

Color Scheme

Press Ctrl+Shift+P (Cmd+Shift+P in macOS), color, Enter to pick a color scheme for the editor. There are also tons of color schemes available for download on the marketplace.

Keyboard Shortcuts

CheatSheet

Windows
macOS

Useful Shortcuts (Linux)

Ctrl+P opens a search box to find and open a file.
F1 or Ctrl+Shift+P opens a search box to find a command (e.g. Tasks: Run Task). Note: if you want to run one of the Predefined tasks in tasks.json, it is faster to just use Ctrl+P > "task ".
Ctrl+K, Ctrl+S opens the key bindings editor.
Ctrl+` toggles the built-in terminal.
Ctrl+Shift+M toggles the problems view (linter warnings, compile errors and warnings). You'll switch a lot between terminal and problem view during compilation.
Alt+O switches between the source/header file.
Ctrl+G jumps to a line.
F12 jumps to the definition of the symbol at the cursor (also available on right-click context menu).
Shift+F12 or F1, CodeSearchReferences, Return shows all references of the symbol at the cursor.
F1, CodeSearchOpen, Return opens the current file in Code Search.
Ctrl+D selects the word at the cursor. Pressing it multiple times multi-selects the next occurrences, so typing in one types in all of them, and Ctrl+U deselects the last occurrence.
Ctrl+K, Z enters Zen Mode, a fullscreen editing mode with nothing but the current editor visible.
Ctrl+X without anything selected cuts the current line. Ctrl+V pastes the line.

*** aside Note: See also Key Bindings for Visual Studio Code .

Java/Android Support

Follow these steps to get full IDE support (outline, autocompletion, jump to definition including automatic decompilation of prebuilts, real-time reporting of compile errors/warnings, Javadocs, etc.) when editing .java files in Chromium:

Add the following to your VS Code workspace settings.json:
```
"java.import.gradle.enabled": false,
"java.import.maven.enabled": false
```
This will prevent the language server from attempting to build all Gradle and Maven projects that can be found anywhere in the Chromium source tree, which typically results in hilarity.
```
"java.jdt.ls.java.home": "<< ABSOLUTE PATH TO YOUR WORKING COPY OF CHROMIUM >>/src/third_party/jdk/current"
```
This one is optional but reduces the likelihood of problems by making sure the language server uses the same JDK as the Chromium build system (as opposed to some random JDK from your host system).
Install the Language Support for Java™ by Red Hat extension. You do not need any other extension.
Build your code in the usual way (i.e. using gn and ninja commands). This will produce build config files that are necessary for the next step. It will also make autogenerated code visible to the language server.
Generate the Eclipse JDT project by running build/android/generate_vscode_project.py from the src directory. For example, if your build output directory is out/Debug-x86 and your build target is //chrome/android:chrome_java, run: build/android/generate_vscode_project.py --output-dir out/Debug-x86 --build-config gen/chrome/android/chrome_java.build_config.json. This will create .project and .classpath in the src directory.
Reload your VS Code window to let it start importing the generated project.
Open a Java source file then wait a couple of minutes for the language server to build the project.
Done! You should now have full Java language support for any .java file that is included in the build.

Known issues

Errors related to GEN_JNI are caused by the language server (rightfully) getting confused about multiple definitions of the autogenerated GEN_JNI class. This is a known quirk of the JNI generator.

Troubleshooting

If you have used the previous instructions to use generate_vscode_classpath.py or you think something went wrong, try clearing the internal state of the language server by executing Java: Clean Java Language Server Workspace from the command palette. This will force the language server to rebuild its internal workspace by importing the generated Eclipse JDT project.

Automatic formatting

Java code in Chromium is formatted using clang-format. To get VS Code to use clang-format to format Java files, install the Clang-Format extension and set it as the default formatter for Java in your workspace settings.json:

"[java]": {
  "editor.defaultFormatter": "xaver.clang-format"
}

To avoid potential formatting differences due to clang-format version skew, it makes sense to configure the extension to run clang-format in the same way git cl format would. You can do this by adding the following to your workspace settings.json:

"clang-format.executable": "<< PATH TO YOUR CHROMIUM WORKING COPY >>/src/buildtools/linux64/clang-format"

Setup For Chromium

VS Code is configured via JSON files. This section describes how to configure it for a better Chromium development experience.

*** aside Note: See VS Code documentation for a more general introduction to VS Code customization.

The Chromium repository comes with some basic configuration. Run the following commands to initialize VS Code for your Chromium checkout:

cd /path/to/chromium/src
mkdir .vscode
cp tools/vscode/*.json .vscode/
cp tools/vscode/cpp.code-snippets .vscode/

Once you have done, proceed to the next sections to install recommended extensions and perform customization.

Install Recommended Extensions

As described in the Useful Extensions sections, there are essential extensions to help Chromium development. Follow the steps below:

In VS Code's Command Palette (Ctrl+P, or Cmd+Shift+P in macOS), type Show Recommended Extensions, and press Enter.
In the WORKSPACE RECOMMENDATIONS section of the EXTENSIONS sidebar, click the Install Workspace Recommended Extensions (shown as a cloud icon).

Now you are all set.

Customize Workspace Settings

Open the file //tools/vscode/settings.json, and check out the default settings there. Feel free to commit added or removed settings to enable better team development, or change settings locally in .vscode/settings.json to suit personal preference.

*** aside Note: these settings assume that the workspace folder (the root folder displayed in the Explorer tab) is Chromium's src/ directory. If this is not the case, replace any references to ${workspaceFolder} with the path to your src/.

Tasks

Next, we'll tell VS Code how to compile our code, run tests, and to read warnings and errors from the build output.

Open the file .vscode/tasks.json. This will provide tasks to do basic things. You might have to adjust the commands to your situation and needs. For example, before running most of the tasks, you'll need to set the chromeOutputDir value in that file.

Now you can run tasks by using Ctrl+P (Cmd+Shift+P in macOS) and typing "task " and then a number of your choice. If you select one of the build tasks, the build output will display in the terminal pane. Jump through build problems quickly using F8 / Shift-F8. See task names for more info on running tasks.

If you have intellisense enabled but do not have include paths set up correctly, jumping through problems will also try to navigate through all the include files it cannot locate and add a lot of noise. You can fix your include path or simply set intellisense to "tag parser" mode by doing the following:

Open Preferences (Ctrl+Shift+P > "Preferences: Open User Settings").
Type "intellisense engine" in the settings search box.
Select "Tag Parser" as the provider.

Note: on a Chromebook, use 🔍+<8th button in the top row that's not ESC>. In most cases, this is the top row button that is the closest to be directly above the 8 key.

Launch Commands

Launch commands are the equivalent of F5 in Visual Studio: They launch some program or a debugger. Optionally, they can run some task defined in tasks.json. Launch commands can be run from the debug view (Ctrl+Shift+D).

Open the file at .vscode/launch.json and adjust the example launch commands to your situation and needs (e.g., the value of "type" needs adjustment for Windows).

Key Bindings

To edit key bindings, press Ctrl+K, Ctrl+S. You'll see the defaults on the left and your overrides on the right stored in the file .vscode/keybindings.json. Please take a look and adjust them to your situation and needs. To change a key binding, copy the corresponding key binding to the right. It's fairly self-explanatory.

You can bind any command to a key, even commands specified by extensions like CodeSearchOpen. For instance, to bind CodeSearchOpen to F2 to , simply add { "key": "F2", "command": "cs.open" },. Note that the command title CodeSearchOpen won't work. You have to get the actual command name from the package.json file of the extension.

If you are used to other editors, you can also install your favorite keymap. For instance, to install eclipse keymaps, install the vscode-eclipse-keybindings extension. More keymaps can be found in the marketplace.

Fixes for Known Issues

Git on Windows

If you only have the depot_tools Git installed on your machine, even though it is in your PATH, VS Code will ignore it as it seems to be looking for git.exe. You will have to add the following to your settings in order for the Git integration to work:

{
  "git.path": "C:\\src\\depot_tools\\git.bat"

  // more settings here...
}

Tip: you can jump to the settings JSON file by using Ctrl+Shift+P and using the "Preferences: Open User Settings (JSON)" verb (for whatever reason, setting git.path as a folder setting does not appear to work).

Remote

*** promo Googlers: See go/vscode-remote instead.

VS Code now has a Remote framework that allows you to use VS Code on your laptop while your code is hosted elsewhere. This really shines when used in conjunction with the vscode-clangd plugin, which allows clangd to run remotely as well.

To get this to run, install the Remote pack extension, and then make sure your ssh config file has your remote connection:

~/.ssh/config:

Host my-connection
  HostName my-remote-host.corp.company.com

VS Code will then list this connection in the 'Remote Explorer' section on the left. To launch VS Code with this connection, click on the '+window' icon next to the listed hostname. It has you choose a folder - use the 'src' folder root. This will open a new VS Code window in 'Remote' mode. Now you can install extensions specifically for your remote connection, like vscode-clangd, etc.

Chromebooks

For Googlers, here are Google-specific instructions for setting up remote development on chromebooks without using Crostini.

Windows & SSH

VS Code remote tools requires 'sshd' which isn't installed on Windows by default.

For Googlers, sshd should already be installed on your workstation, and VS Code should work remotely if you followed the setup instructions at go/building-chrome-win. If you are still having problems, please refer to go/vscode-remote#windows.

Non-Googlers may follow Microsoft's instructions for installing the OpenSSH server. VS Code should work remotely after following this step.

Snippets

There are some useful snippets provided in //tools/vscode/cpp.json, which are already installed to your workspace at .vscode/cpp.code-snippets

Tips

The `out` folder

Automatically generated code is put into a subfolder of out/, which means that these files are ignored by VS Code (see files.exclude above) and cannot be opened e.g. from quick-open (Ctrl+P). As of version 1.21, VS Code does not support negated glob commands, but you can define a set of exclude pattern to include only out/Debug/gen:

"files.exclude": {
  // Ignore build output folders. Except out/Debug/gen/
  "out/[^D]*/": true,
  "out/Debug/[^g]*": true,
  "out/Debug/g[^e]*": true,
  "out_*/**": true,
},

Once it does, you can use

"!out/Debug/gen/**": true

in files.exclude instead of the symlink.

Using VS Code as git editor

Add [core] editor = "code --wait" to your ~/.gitconfig file in order to use VS Code as editor for git commit messages etc. Note that the editor starts up significantly slower than nano or vim. To use VS Code as merge tool, add [merge] tool = code.

Task Names

Note that we named the tasks 1-build_chrome_debug, 2-build_chrome_release etc. This allows you to quickly execute tasks by pressing their number: Press Ctrl+P and enter task <n>, where <n> is the number of the task. You can also create a keyboard shortcut for running a task. File > Preferences > Keyboard Shortcuts and add { "key": "ctrl+r", "command": "workbench.action.tasks.runTask", "when": "!inDebugMode" }. Then it's sufficient to press Ctrl+R and enter <n>.

Working on Laptop

You might want to disable git status autorefresh to save battery.

"git.autorefresh": false,

Editing in multiple Git repositories

If you frequently work in multiple Git repositories that are part of the Chromium repository, you might find that the built-in tooling does not work as expected for files that exist below folders that are part of a .gitignore file checked in to Chromium.

To work around this, you can add the directories you edit as separate folders entries in your workspace configuration, and ensure that the directories that are ignored in Chromium are listed before the Chromium src path.

To edit this, go to Settings -> Select the Workspace tab, and choose to open as JSON (button in the top right), and configure folders like this (change paths to match your local setup and usage):

{
  "folders": [
    {
      "path": "chromium/src/third_party/perfetto"
    },
    {
      "path": "chromium/src"
    }
  ]
}

Unable to open $File resource is not available when debugging Chromium on Linux

Chromium recently changed the file path to be relative to the output dir. Check gn args out/$dir --list if strip_absolute_paths_from_debug_symbols is true (which is the default), set cwd to the output dir. otherwise, set cwd to ${workspaceFolder}.

More

More tips and tricks can be found here.

Files

vscode.md

Latest commit

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