1# Debugger
2
3Zed uses the [Debug Adapter Protocol (DAP)](https://microsoft.github.io/debug-adapter-protocol/) to provide debugging functionality across multiple programming languages.
4DAP is a standardized protocol that defines how debuggers, editors, and IDEs communicate with each other.
5It allows Zed to support various debuggers without needing to implement language-specific debugging logic.
6
7This protocol enables features like setting breakpoints, stepping through code, inspecting variables,
8and more, in a consistent manner across different programming languages and runtime environments.
9
10> We currently offer onboarding support for users. We are eager to hear from you if you encounter any issues or have suggestions for improvement for our debugging experience.
11> You can schedule a call via [Cal.com](https://cal.com/team/zed-research/debugger)
12
13## Supported Debug Adapters
14
15Zed supports a variety of debug adapters for different programming languages out of the box:
16
17- JavaScript ([vscode-js-debug](https://github.com/microsoft/vscode-js-debug.git)): Enables debugging of Node.js applications, including setting breakpoints, stepping through code, and inspecting variables in JavaScript.
18
19- Python ([debugpy](https://github.com/microsoft/debugpy.git)): Provides debugging capabilities for Python applications, supporting features like remote debugging, multi-threaded debugging, and Django/Flask application debugging.
20
21- LLDB ([CodeLLDB](https://github.com/vadimcn/codelldb.git)): A powerful debugger for Rust, C, C++, and some other compiled languages, offering low-level debugging features and support for Apple platforms.
22
23- GDB ([GDB](https://sourceware.org/gdb/)): The GNU Debugger, which supports debugging for multiple programming languages including C, C++, Go, and Rust, across various platforms.
24
25- Go ([Delve](https://github.com/go-delve/delve)): Delve, a debugger for the Go programming language, offering both local and remote debugging capabilities with full support for Go's runtime and standard library.
26
27- PHP ([Xdebug](https://xdebug.org/)): Provides debugging and profiling capabilities for PHP applications, including remote debugging and code coverage analysis.
28
29- Ruby ([rdbg](https://github.com/ruby/debug)): Provides debugging for Ruby.
30
31These adapters enable Zed to provide a consistent debugging experience across multiple languages while leveraging the specific features and capabilities of each debugger.
32
33> Is your desired debugger not listed? You can install a [Debug Adapter extension](https://zed.dev/extensions?filter=debug-adapters) to add support for your favorite debugger.
34> If that's not enough, you can contribute by creating an extension yourself. Check out our [debugger extensions](extensions/debugger-extensions.md) documentation for more information.
35
36## Getting Started
37
38For basic debugging, you can set up a new configuration by opening the `New Session Modal` either via the `debugger: start` (default: f4) or by clicking the plus icon at the top right of the debug panel.
39
40For more advanced use cases, you can create debug configurations by directly editing the `.zed/debug.json` file in your project root directory.
41
42You can then use the `New Session Modal` to select a configuration and start debugging.
43
44### Launching & Attaching
45
46Zed debugger offers two ways to debug your program; you can either _launch_ a new instance of your program or _attach_ to an existing process.
47Which one you choose depends on what you are trying to achieve.
48
49When launching a new instance, Zed (and the underlying debug adapter) can often do a better job at picking up the debug information compared to attaching to an existing process, since it controls the lifetime of a whole program.
50Running unit tests or a debug build of your application is a good use case for launching.
51
52Compared to launching, attaching to an existing process might seem inferior, but that's far from truth; there are cases where you cannot afford to restart your program, because for example, the bug is not reproducible outside of a production environment or some other circumstances.
53
54## Configuration
55
56While configuration fields are debug adapter-dependent, most adapters support the following fields:
57
58```json
59[
60 {
61 // The label for the debug configuration and used to identify the debug session inside the debug panel & new session modal
62 "label": "Example Start debugger config",
63 // The debug adapter that Zed should use to debug the program
64 "adapter": "Example adapter name",
65 // Request:
66 // - launch: Zed will launch the program if specified or shows a debug terminal with the right configuration
67 // - attach: Zed will attach to a running program to debug it or when the process_id is not specified we will show a process picker (only supported for node currently)
68 "request": "launch",
69 // program: The program that you want to debug
70 // This field supports path resolution with ~ or . symbols
71 "program": "path_to_program",
72 // cwd: defaults to the current working directory of your project ($ZED_WORKTREE_ROOT)
73 "cwd": "$ZED_WORKTREE_ROOT"
74 }
75]
76```
77
78All configuration fields support [task variables](./tasks.md#variables).
79
80### Build tasks
81
82Zed also allows embedding a Zed task in a `build` field that is run before the debugger starts. This is useful for setting up the environment or running any necessary setup steps before the debugger starts.
83
84```json
85[
86 {
87 "label": "Build Binary",
88 "adapter": "CodeLLDB",
89 "program": "path_to_program",
90 "request": "launch",
91 "build": {
92 "command": "make",
93 "args": ["build", "-j8"]
94 }
95 }
96]
97```
98
99Build tasks can also refer to the existing tasks by unsubstituted label:
100
101```json
102[
103 {
104 "label": "Build Binary",
105 "adapter": "CodeLLDB",
106 "program": "path_to_program",
107 "request": "launch",
108 "build": "my build task" // Or "my build task for $ZED_FILE"
109 }
110]
111```
112
113### Automatic scenario creation
114
115Given a Zed task, Zed can automatically create a scenario for you. Automatic scenario creation also powers our scenario creation from gutter.
116Automatic scenario creation is currently supported for Rust, Go, and Python. JavaScript/TypeScript support is being worked on.
117
118### Example Configurations
119
120#### JavaScript
121
122##### Debug Active File
123
124```json
125[
126 {
127 "label": "Debug with node",
128 "adapter": "JavaScript",
129 "program": "$ZED_FILE",
130 "request": "launch",
131 "console": "integratedTerminal",
132 "type": "pwa-node"
133 }
134]
135```
136
137##### Attach debugger to a server running in web browser (`npx serve`)
138
139Given an externally-ran web server (e.g., with `npx serve` or `npx live-server`) one can attach to it and open it with a browser.
140
141```json
142[
143 {
144 "label": "Inspect ",
145 "adapter": "JavaScript",
146 "type": "pwa-chrome",
147 "request": "launch",
148 "url": "http://localhost:5500", // Fill your URL here.
149 "program": "$ZED_FILE",
150 "webRoot": "${ZED_WORKTREE_ROOT}"
151 }
152]
153```
154
155#### Python
156
157##### Debug Active File
158
159```json
160[
161 {
162 "label": "Python Active File",
163 "adapter": "Debugpy",
164 "program": "$ZED_FILE",
165 "request": "launch"
166 }
167]
168```
169
170##### Flask App
171
172For a common Flask Application with a file structure similar to the following:
173
174```
175.venv/
176app/
177 init.py
178 main.py
179 routes.py
180templates/
181 index.html
182static/
183 style.css
184requirements.txt
185```
186
187…the following configuration can be used:
188
189```json
190[
191 {
192 "label": "Python: Flask",
193 "adapter": "Debugpy",
194 "request": "launch",
195 "module": "app",
196 "cwd": "$ZED_WORKTREE_ROOT",
197 "env": {
198 "FLASK_APP": "app",
199 "FLASK_DEBUG": "1"
200 },
201 "args": [
202 "run",
203 "--reload", // Enables Flask reloader that watches for file changes
204 "--debugger" // Enables Flask debugger
205 ],
206 "autoReload": {
207 "enable": true
208 },
209 "jinja": true,
210 "justMyCode": true
211 }
212]
213```
214
215#### Rust/C++/C
216
217##### Using pre-built binary
218
219```json
220[
221 {
222 "label": "Debug native binary",
223 "program": "$ZED_WORKTREE_ROOT/build/binary",
224 "request": "launch",
225 "adapter": "CodeLLDB" // GDB is available on non arm macs as well as linux
226 }
227]
228```
229
230##### Build binary then debug
231
232```json
233[
234 {
235 "label": "Build & Debug native binary",
236 "build": {
237 "command": "cargo",
238 "args": ["build"]
239 },
240 "program": "$ZED_WORKTREE_ROOT/target/debug/binary",
241 "request": "launch",
242 "adapter": "CodeLLDB" // GDB is available on non arm macs as well as linux
243 }
244]
245```
246
247#### TypeScript
248
249##### Attach debugger to a server running in web browser (`npx serve`)
250
251Given an externally-ran web server (e.g., with `npx serve` or `npx live-server`) one can attach to it and open it with a browser.
252
253```json
254[
255 {
256 "label": "Launch Chrome (TypeScript)",
257 "adapter": "JavaScript",
258 "type": "pwa-chrome",
259 "request": "launch",
260 "url": "http://localhost:5500",
261 "program": "$ZED_FILE",
262 "webRoot": "${ZED_WORKTREE_ROOT}",
263 "sourceMaps": true,
264 "build": {
265 "command": "npx",
266 "args": ["tsc"]
267 }
268 }
269]
270```
271
272#### Go
273
274Zed uses [delve](https://github.com/go-delve/delve?tab=readme-ov-file) to debug Go applications.
275Zed will automatically create debug scenarios for `func main` in your main packages, and also
276for any tests, so you can use the Play button in the gutter to debug these without configuration.
277
278##### Debug Go Packages
279
280To debug a specific package, you can do so by setting the Delve mode to "debug". In this case "program" should be set to the package name.
281
282```json
283[
284 {
285 "label": "Go (Delve)",
286 "adapter": "Delve",
287 "program": "$ZED_FILE",
288 "request": "launch",
289 "mode": "debug"
290 }
291]
292```
293
294```json
295[
296 {
297 "label": "Run server",
298 "adapter": "Delve",
299 "request": "launch",
300 "mode": "debug",
301 // For Delve, the program can be a package name
302 "program": "./cmd/server"
303 // "args": [],
304 // "buildFlags": [],
305 }
306]
307```
308
309##### Debug Go Tests
310
311To debug the tests for a package, set the Delve mode to "test".
312The "program" is still the package name, and you can use the "buildFlags" to do things like set tags, and the "args" to set args on the test binary. (See `go help testflags` for more information on doing that).
313
314```json
315[
316 {
317 "label": "Run integration tests",
318 "adapter": "Delve",
319 "request": "launch",
320 "mode": "test",
321 "program": ".",
322 "buildFlags": ["-tags", "integration"]
323 // To filter down to just the test your cursor is in:
324 // "args": ["-test.run", "$ZED_SYMBOL"]
325 }
326]
327```
328
329##### Build and debug separately
330
331If you need to build your application with a specific command, you can use the "exec" mode of Delve. In this case "program" should point to an executable,
332and the "build" command should build that.
333
334```json
335{
336 "label": "Debug Prebuilt Unit Tests",
337 "adapter": "Delve",
338 "request": "launch",
339 "mode": "exec",
340 "program": "${ZED_WORKTREE_ROOT}/__debug_unit",
341 "args": ["-test.v", "-test.run=${ZED_SYMBOL}"],
342 "build": {
343 "command": "go",
344 "args": [
345 "test",
346 "-c",
347 "-tags",
348 "unit",
349 "-gcflags\"all=-N -l\"",
350 "-o",
351 "__debug_unit",
352 "./pkg/..."
353 ]
354 }
355}
356```
357
358##### Attaching to an existing instance of Delve
359
360You might find yourself needing to connect to an existing instance of Delve that's not necessarily running on your machine; in such case, you can use `tcp_arguments` to instrument Zed's connection to Delve.
361
362```
363{
364 "adapter": "Delve",
365 "label": "Connect to a running Delve instance",
366 "program": "/Users/zed/Projects/language_repositories/golang/hello/hello",
367 "cwd": "/Users/zed/Projects/language_repositories/golang/hello",
368 "args": [],
369 "env": {},
370 "request": "launch",
371 "mode": "exec",
372 "stopOnEntry": false,
373 "tcp_connection": { "host": "123.456.789.012", "port": 53412 }
374}
375```
376
377In such case Zed won't spawn a new instance of Delve, as it opts to use an existing one. The consequence of this is that _there will be no terminal_ in Zed; you have to interact with the Delve instance directly, as it handles stdin/stdout of the debuggee.
378
379#### Ruby
380
381To run a ruby task in the debugger, you will need to configure it in the `.zed/debug.json` file in your project. We don't yet have automatic detection of ruby tasks, nor do we support connecting to an existing process.
382
383The configuration should look like this:
384
385```json
386[
387 {
388 "adapter": "Ruby",
389 "label": "Run CLI",
390 "script": "cli.rb"
391 // If you want to customize how the script is run (for example using bundle exec)
392 // use "command" instead.
393 // "command": "bundle exec cli.rb"
394 //
395 // "args": []
396 // "env": {}
397 // "cwd": ""
398 }
399]
400```
401
402## Breakpoints
403
404To set a breakpoint, simply click next to the line number in the editor gutter.
405Breakpoints can be tweaked depending on your needs; to access additional options of a given breakpoint, right-click on the breakpoint icon in the gutter and select the desired option.
406At present, you can:
407
408- Add a log to a breakpoint, which will output a log message whenever that breakpoint is hit.
409- Make the breakpoint conditional, which will only stop at the breakpoint when the condition is met. The syntax for conditions is adapter-specific.
410- Add a hit count to a breakpoint, which will only stop at the breakpoint after it's hit a certain number of times.
411- Disable a breakpoint, which will prevent it from being hit while leaving it visible in the gutter.
412
413Some debug adapters (e.g. CodeLLDB and JavaScript) will also _verify_ whether your breakpoints can be hit; breakpoints that cannot be hit are surfaced more prominently in the UI.
414
415All breakpoints enabled for a given project are also listed in "Breakpoints" item in your debugging session UI. From "Breakpoints" item in your UI you can also manage exception breakpoints.
416The debug adapter will then stop whenever an exception of a given kind occurs. Which exception types are supported depends on the debug adapter.
417
418## Settings
419
420- `dock`: Determines the position of the debug panel in the UI.
421- `stepping_granularity`: Determines the stepping granularity.
422- `save_breakpoints`: Whether the breakpoints should be reused across Zed sessions.
423- `button`: Whether to show the debug button in the status bar.
424- `timeout`: Time in milliseconds until timeout error when connecting to a TCP debug adapter.
425- `log_dap_communications`: Whether to log messages between active debug adapters and Zed.
426- `format_dap_log_messages`: Whether to format DAP messages when adding them to the debug adapter logger.
427
428### Dock
429
430- Description: The position of the debug panel in the UI.
431- Default: `bottom`
432- Setting: debugger.dock
433
434**Options**
435
4361. `left` - The debug panel will be docked to the left side of the UI.
4372. `right` - The debug panel will be docked to the right side of the UI.
4383. `bottom` - The debug panel will be docked to the bottom of the UI.
439
440```json
441"debugger": {
442 "dock": "bottom"
443},
444```
445
446### Stepping granularity
447
448- Description: The Step granularity that the debugger will use
449- Default: line
450- Setting: debugger.stepping_granularity
451
452**Options**
453
4541. Statement - The step should allow the program to run until the current statement has finished executing.
455 The meaning of a statement is determined by the adapter and it may be considered equivalent to a line.
456 For example 'for(int i = 0; i < 10; i++)' could be considered to have 3 statements 'int i = 0', 'i < 10', and 'i++'.
457
458```json
459{
460 "debugger": {
461 "stepping_granularity": "statement"
462 }
463}
464```
465
4662. Line - The step should allow the program to run until the current source line has executed.
467
468```json
469{
470 "debugger": {
471 "stepping_granularity": "line"
472 }
473}
474```
475
4763. Instruction - The step should allow one instruction to execute (e.g. one x86 instruction).
477
478```json
479{
480 "debugger": {
481 "stepping_granularity": "instruction"
482 }
483}
484```
485
486### Save Breakpoints
487
488- Description: Whether the breakpoints should be saved across Zed sessions.
489- Default: true
490- Setting: debugger.save_breakpoints
491
492**Options**
493
494`boolean` values
495
496```json
497{
498 "debugger": {
499 "save_breakpoints": true
500 }
501}
502```
503
504### Button
505
506- Description: Whether the button should be displayed in the debugger toolbar.
507- Default: true
508- Setting: debugger.show_button
509
510**Options**
511
512`boolean` values
513
514```json
515{
516 "debugger": {
517 "show_button": true
518 }
519}
520```
521
522### Timeout
523
524- Description: Time in milliseconds until timeout error when connecting to a TCP debug adapter.
525- Default: 2000
526- Setting: debugger.timeout
527
528**Options**
529
530`integer` values
531
532```json
533{
534 "debugger": {
535 "timeout": 3000
536 }
537}
538```
539
540### Log Dap Communications
541
542- Description: Whether to log messages between active debug adapters and Zed. (Used for DAP development)
543- Default: false
544- Setting: debugger.log_dap_communications
545
546**Options**
547
548`boolean` values
549
550```json
551{
552 "debugger": {
553 "log_dap_communications": true
554 }
555}
556```
557
558### Format Dap Log Messages
559
560- Description: Whether to format DAP messages when adding them to the debug adapter logger. (Used for DAP development)
561- Default: false
562- Setting: debugger.format_dap_log_messages
563
564**Options**
565
566`boolean` values
567
568```json
569{
570 "debugger": {
571 "format_dap_log_messages": true
572 }
573}
574```
575
576### Customizing Debug Adapters
577
578- Description: Custom program path and arguments to override how Zed launches a specific debug adapter.
579- Default: Adapter-specific
580- Setting: `dap.$ADAPTER.binary` and `dap.$ADAPTER.args`
581
582You can pass `binary`, `args`, or both. `binary` should be a path to a _debug adapter_ (like `lldb-dap`) not a _debugger_ (like `lldb` itself). The `args` setting overrides any arguments that Zed would otherwise pass to the adapter.
583
584```json
585{
586 "dap": {
587 "CodeLLDB": {
588 "binary": "/Users/name/bin/lldb-dap",
589 "args": ["--wait-for-debugger"]
590 }
591 }
592}
593```
594
595## Theme
596
597The Debugger supports the following theme options:
598
599- `debugger.accent`: Color used to accent breakpoint & breakpoint-related symbols
600- `editor.debugger_active_line.background`: Background color of active debug line
601
602## Troubleshooting
603
604If you're running into problems with the debugger, please [open a GitHub issue](https://github.com/zed-industries/zed/issues/new?template=04_bug_debugger.yml) or [schedule an onboarding call](https://cal.com/team/zed-research/debugger) with us so we can help understand and fix your issue.
605
606There are also some features you can use to gather more information about the problem:
607
608- When you have a session running in the debug panel, you can run the `dev: copy debug adapter arguments` action to copy a JSON blob to the clipboard that describes how Zed initialized the session. This is especially useful when the session failed to start, and is great context to add if you open a GitHub issue.
609- You can also use the `dev: open debug adapter logs` action to see a trace of all of Zed's communications with debug adapters during the most recent debug sessions.