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Visual Studio Code Dev

Get started here.

Visual Studio Code (VS Code) is a free, open source, lightweight and powerful code editor for Windows, Mac 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. Windows and Mac might require a slightly different setup (e.g. Ctrl -> Cmd). Please update this page accordingly.

Setup

Installation

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

Follow the steps on Setting up Visual Studio Code.

Usage

To run it on Linux, just navigate to Chromium's src folder and type code . in a terminal. The argument to code is the base directory of the workspace. VS Code does not require project or solution files. However, it does store workspace settings in a .vscode folder in your base directory.

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

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).

Useful Extensions

Up to now, you have a basic version of VS Code without much language support. Next, we will install some useful extensions. Jump to the extensions window (Ctrl+Shift+X) and install the extensions, or run the following commands.

You will most likely use the following extensions every day:

$ echo "ms-vscode.cpptools llvm-vs-code-extensions.vscode-clangd ms-python.python bbenoist.togglehs peterj.proto Google.vscode-mojom msedge-dev.gnls stkb.rewrap ms-vscode-remote.remote-ssh eamodio.gitlens" | xargs -n 1 code --force --install-extension
  • 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 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.
  • 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).
  • 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.
  • Protobuf support - 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.

The following extensions might be useful for you as well:

$ echo "wmaurer.change-case shd101wyy.markdown-preview-enhanced Gruntfuggly.todo-tree alefragnani.Bookmarks spmeesseman.vscode-taskexplorer streetsidesoftware.code-spell-checker tht13.html-preview-vscode anseki.vscode-color" | xargs -n 1 code --force --install-extension
  • chromium-codesearch - Mac and Linux only: adds ability to open the current line in Chromium Code Search. All other functionality is deprecated, so currently only of limited usefulness.
  • 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.

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

Color Scheme

Press Ctrl+Shift+P, 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

Useful Shortcuts

  • 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

Before anything, add these to your settings.json.

// LightWeight is the language support, the feature we care about. The other
// modes include build functionality with Maven and Gradle. They try to build
// on their own and end up showing thousands of errors.
"java.server.launchMode": "LightWeight",
// Avoids overwriting the custom .classpath file (c.f. next section).
"java.configuration.updateBuildConfiguration": "disabled",

Then install the "Language Support for Java" extension. If you installed it before setting the configs above, uninstall, delete the folder (c.f. next section) and reinstall. You also don't need any of the remaining extensions in "Extension Pack for Java".

Setting up code completion/reference finding/etc.

You'll need to generate a placeholder .classpath file and locate it. In order to generate it, right click on any Java source folder in the left panel and choose "Add folder to java source path". Its location will depend on whether you're doing local or remote development. Local path on linux will look something like:

~/.vscode/data/User/workspaceStorage/<hash>/redhat.java/jdt_ws/<project>/.classpath

You might find multiple folders when looking for <project>. Choose anything except jdt.ls-java-project. If you only see jdt.ls-java-project, try using the "Add folder to java source path" option again.

If doing remote development, the file will be under ~/.vscode-server/ on your remote machine.

You'll need to replace all of the contents of that file with the contents of tools/android/eclipse/.classpath (external) or clank/development/ide/eclipse/.classpath (generated by gclient runhooks for Chrome developers), and then replace some paths as vscode interprets some paths differently from eclipse.

  • Replace: kind="src" path=" with kind="src" path="_/
    • eg. <classpathentry kind="src" path="_/android_webview/glue/java/src"/>
  • Replace: kind="lib" path="../src with kind="lib" path="_
    • eg. <classpathentry kind="lib" path="_/out/Debug/lib.java/base/base_java.jar"/>
  • Remove all nested paths (or exclude them from their parents). At time of writing:
    • third_party/android_protobuf/src/java/src/main/java
    • third_party/junit/src/src/main/java

Also, make sure export ANDROID_HOME=/usr/local/google/home/{your_ldap}/Android/Sdk is in the remote machine's ~/.bashrc.

Then restart vscode, open a Java file, and wait for a bit.

Debugging tips:

  • Right clicking on a folder in vscode and clicking "Add folder to java source path" will error if there are syntax problems with your classpath. (Don't use this actually add new paths to your classpath as it won't work correctly)
    • If there are no syntax errors, ensure the correct .classpath file is being used by seeing if the folder was actually added to the .classpath file you edited.

Setup For Chromium

VS Code is configured via JSON files. This paragraph contains JSON configuration files that are useful for Chromium development, in particular. See VS Code documentation for an introduction to VS Code customization.

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 to suit personal preference.

To use these settings wholesale, enter the following commands into your terminal while at the src directory:

$ mkdir .vscode/
$ cp tools/vscode/settings.json .vscode

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 //tools/vscode/tasks.json. This will provide tasks to do basic things. You might have to adjust the commands to your situation and needs. To use these settings wholesale, enter the following command into your terminal:

$ cp tools/vscode/tasks.json .vscode

Before running most of the tasks, you'll need to set the chromeOutputDir value in your .vscode/tasks.json file.

Now you can run tasks by using Ctrl+P 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:

  1. Open Preferences (Ctrl+Shift+P > "Preferences: Open User Settings").
  2. Type "intellisense engine" in the settings search box.
  3. 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 //tools/vscode/launch.json and adjust the example launch commands to your situation and needs (e.g., the value of "type" needs adjustment for Windows). To use these settings wholesale, enter the following command into your terminal:

$ cp tools/vscode/launch.json .vscode

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 keybindings.json. 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.

Some key bindings that are likely to be useful for you are available at //tools/vscode/keybindings.json. Please take a look and adjust them to your situation and needs. To use these settings wholesale, enter the following command into your terminal:

$ cp tools/vscode/keybindings.json .vscode

Remote

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

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 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.

You can either install them in your user profile (path may vary depending on the platform):

$ mkdir -p ~/.config/Code/User/snippets
$ cp tools/vscode/cpp.json ~/.config/Code/User/snippets

Or install them as project snippets:

$ cp tools/vscode/cpp.json .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.