Bazel

Bazel is an open-source build and test tool developed by Google. It is designed to manage large codebases with complex dependencies across multiple languages and platforms. Bazel automates the process of compiling code, linking dependencies, running tests, and deploying artifacts.

Install the Bazel plugin

Bazel support is provided by the Bazel for CLion plugin, which you can install from the IDE.

Press Ctrl+Alt+S to open settings and then select Plugins.
Open the Marketplace tab, find the Bazel for CLion plugin, and click Install.
Restart the IDE to activate the plugin.

Open a project

Open a Bazel project

Click Open on the Welcome screen.
Alternatively, go to File | Open in the main menu.
In the dialog that opens, specify the path to the project sources.

You can watch the process of importing the project in the Build tool window:

The Build tool window in the process of a Bazel project sync

Configure a project view

CLion uses a .bazelproject file to determine which part of a Bazel workspace to load and to provide its source files with code insight features. Each file is a self-contained project configuration: it describes which directories and targets are imported and which build flags are forwarded to Bazel when CLion syncs and resolves the code.

After a Bazel project opens, CLion creates the default project view file located in the .clwb folder. This file loads the whole workspace. Besides this auto-generated file, you may already have existing project view files, which you can switch to. An active .bazelproject file is marked as current in the Project tool window.

An active .bazelproject file marked as current in the Project tool window

Here is an example of the contents of such a file:

                directories:
                    calc

                derive_targets_from_directories: false

                targets:
                    //calc/...

                build_flags:
                    --compilation_mode=dbg
            

Section	Description
`directories`	Specifies the workspace directories that CLion should include in the Bazel project. You can use `directories: .` to include the workspace root. Use `-some_dir` to exclude a specific directory. These directories are also used as the scope for automatic target discovery when `derive_targets_from_directories` is enabled.
`derive_targets_from_directories`	If set to `true`, CLion derives available Bazel targets from the specified `directories`, so you do not need to list targets manually. If set to `false`, you need to specify the exact targets in `targets`, which is recommended for large projects.
`targets`	Specifies Bazel targets that CLion should import and sync. Use this section to explicitly control which build, run, and test targets are available in the IDE. CLion supports target patterns such as `//calc/...` and `//calc:all`.
`build_flags`	Specifies additional Bazel command-line flags that CLion passes to Bazel build invocations. Use this for options such as configurations, defines, platforms, or toolchain-related settings.

You can start with only directories and targets and add more sections if you want to further tweak your IDE workspace.

Choose a sync mode

CLion supports three key sync modes available in the main menu (Bazel | Sync):

The Bazel | Sync submenu in the main menu, listing the sync modes available for a CLion Bazel project

Sync Project with BUILD Files

The default sync mode. Use it for most day-to-day changes.

To sync, you can also click the Sync Project with BUILD Files button in the toolbar:

The CLion main toolbar with the Sync Project with BUILD Files button that starts a Bazel project sync

Non-Incrementally Sync Project with BUILD Files

Discards the sync cache and reimports the project from scratch. Use it as a first troubleshooting step.

Partially Sync

Reimports a single directory. Use it when you change build definitions in one directory only. The action is also available from the context menu when you right-click the corresponding directory in the Project tool window.

Switch an active configuration

CLion tracks one active project view at a time. To switch, right-click the required .bazelproject file in the Project tool window and select Switch Project View.

Switching the active project view in the Project tool window

This triggers a resync: CLion reimports the selected scope and resolves the corresponding source files again.

Here is an example of switching to the appropriate configuration, after which the code resolves and the gutter buttons appear next to TEST:

Before switching the active project view

After switching, only the directories listed in the calc-advanced.bazelproject file appear in the Project tool window.

Run C/C++ Bazel targets

To run an individual test, open its source file and click the Run icon in the gutter next to the test:

A C++ test file in the editor with the gutter menu open next to a TEST macro and the Run action for a Bazel test target

From the Project tool window, you can also run all test targets at once. Right-click a directory and select Run 'your_Bazel_target'.

The context menu of a directory in the Project tool window with the Run action for the corresponding Bazel test target

Debug C/C++ Bazel targets

CLion checks whether your project is built with debug symbols instead of automatically injecting debug flags. If the compile and link arguments that Bazel records do not contain the flags the debugger needs, CLion shows a Debug Info Warning dialog after you launch the session.

A Debug Info Warning dialog that appears after launching a session

You can inject debug flags directly from this dialog by selecting Inject Debug Flags and Retry, and the debug session will then continue. Note that with this option selected, CLion has to rebuild your project, which takes more time the larger your project is. This also implies that CLion injects flags that it assumes you are missing, and these flags may not match every project's build setup. This is why the default option is Abort, which lets you specify build_flags in your .bazelproject file manually.

To revert to the default CLion heuristics, add inject_debug_flags: true to your .bazelproject file.

Learn more about this mechanism in the GitHub documentation.

Starlark support

Starlark is a small, Python-like configuration language that Bazel uses to define build targets, rules, macros, and extensions, typically in BUILD, BUILD.bazel, and .bzl files. In CLion, you can debug Starlark code and use REPL (Read-Eval-Print Loop), an interactive interpreter that evaluates Starlark expressions or statements.

Debug Starlark code

Set a breakpoint in your .bzl file.
In the BUILD file, click the Run icon in the gutter next to the debug configuration and select Debug Starlark: 'your_Bazel_target'.
The debug session starts and stops at the breakpoint, and you can then inspect your code, for example, a Starlark macro.

Use REPL

REPL is useful for quickly checking Starlark syntax, trying small code snippets, or experimenting with functions without creating a .bzl file.

Go to Bazel in the main menu and select Starlark REPL. The tool will open in the Run tool window.
Insert a Starlark expression or statement and press Enter to evaluate it.

12 August 2026