vimspector - A multi language graphical debugger for Vim

For a tutorial and usage overview, take a look at the Vimspector website

• Features and Usage
  • Supported debugging features
  • Supported languages:
  • Languages known to work
  • Other languages
• Installation
  • Dependencies
  • Language dependencies
  • Clone the plugin
  • Install some gadgets
  • Manual gadget installation
    • The gadget directory
• About
  • Background
  • Status
    • Experimental
• Mappings
  • Visual Studio / VSCode
  • Human Mode
• Usage
  • Launch and attach by PID:
  • Breakpoints
  • Stepping
  • Variables and scopes
  • Watches
  • Stack Traces
  • Program Output:
    • Console
• Debug adapter configuration
  • Supported Languages
  • Partially supported
  • Unsupported
• FAQ
• License

Features and Usage

The plugin is a capable Vim graphical debugger for multiple languages. It's mostly tested for c++ and python, but in theory supports any language that Visual Studio Code supports (but see caveats).

The Vimspector website has an overview of the UI, along with basic instructions for configuration and setup.

Supported debugging features

• breakpoints (function, line and exception breakpoints)
• step in/out/over/up, stop, restart
• launch and attach
• remote launch, remote attach
• locals and globals display
• watch expressions
• call stack and navigation
• variable value display hover
• interactive debug console
• launch debugee within Vim's embedded terminal
• logging/stdout display

Supported languages:

The following languages are used frequently by the author and are known to work with little effort, and are supported as first-class languages.

• C, C++, etc. (languages supported by gdb or lldb)
• Python 2 and Python 3
• TCL
• Bash scripts

Languages known to work

The following languages are used frequently by the author, but require some sort of hackery that makes it challenging to support generally. These languages are on a best-efforts basis:

• Java (see caveats)
• C# (c-sharp) using dotnet core
• Go (requires separate installation of Delve)
• Node.js (requires node <12 for installation)
• Anything running in chrome (i.e. javascript).

Languages known not to work

• C# (c-sharp) using mono debug adapter (vimspector unable to set breakpoints)

Other languages

Vimspector should work for any debug adapter that works in Visual Studio Code, but there are certain limitations (see FAQ). If you're trying to get vimspector to work with a language that's not "supported", head over to Gitter and contact the author. It should be possible to get it going.

Installation

There are 2 installation methods:

• Using a release tarball, or
• Manually

Release tarballs come with debug adapters for the default languages pre-packaged. To use a release tarball:

1. Check the dependencies
2. Untar the release tarball for your OS into $HOME/.vim/pack:

$ mkdir -p $HOME/.vim/pack
$ curl -L <url> | tar -C $HOME/.vim/pack zxvf - 

3. Configure your project's debug profiles (create .vimspector.json)

Alternatively, you can clone the repo and select which gadgets are installed:

1. Check the dependencies
2. Install the plugin as a Vim package. See :help packages.
3. Install some 'gadgets' (debug adapters)
4. Configure your project's debug profiles (create .vimspector.json)

Dependencies

Vimspector requires:

• Vim version 8.1 with at least patch 1264
• One of the following operating systems:
  • Linux
  • macOS Mojave or pater

Why such a new vim ? Well 2 reasons:

1. Because vimspector uses a lot of new Vim features
2. Because there are Vim bugs that vimspector triggers that will frustrate you if you hit them.

Why no Windows support? Because it's effort and it's not a priority for the author. PRs are welcome.

Which Linux versions? I only test on Ubuntu 18.04 and later and RHEL 6.5 and RHEL 7.6.

Language dependencies

The debug adapters themselves have certain runtime dependencies:

Language	Status	Switch	Adapter	Dependencies
C, C++, etc.	Supported	--all or --enable-c	vscode-cpptools	mono-core
Python	Supported	--all or --enable-python	vscode-python	Python 2.7 or Python 3
TCL	Experimental	--all or --enable-tcl	tclpro	TCL 8.5
Bourne Shell	Experimental	--all or --enable-bash	vscode-bash-debug	Bash v??
C# (dotnet core)	Experimental	--force-enable-csharp	netcoredbg	DotNet core
C# (mono)	Experimental	--force-enable-csharp	vscode-mono-debug	Mono
Go	Experimental	--enable-go	vscode-go	Go, Delve
Node.js	Experimental	--force-enable-node	vscode-node-debug2	6 < Node < 12, Npm
Javascript	Experimental	--force-enable-chrome	debugger-for-chrome	Chrome

For other languages, you'll need some other way to install the gadget.

Clone the plugin

There are many Vim plugin managers, and I'm not going to state a particular preference, so if you choose to use one, you're on your own with installation issues.

Install vimspector as a Vim package, either by cloning this repository into your package path, like this:

$ git clone https://github.com/puremourning/vimspector ~/.vim/pack/vimspector/opt/vimspector

2. Configure vimspector in your .vimrc:

let g:vimspector_enable_mappings = 'HUMAN'

3. Load vimspector at runtime. This can also be added to your .vimrc after configuring vimspector:

packadd! vimspector

See support/doc/example_vimrc.vim.

Also, if you want to try out vimspector without changing your vim config, run:

vim -Nu /path/to/vimspector/tests/vimrc --cmd "let g:vimspector_enable_mappings='HUMAN'"

Install some gadgets

There are a couple of ways of doing this, but using install_gadget.py is highly recommended where that's an option.

For supported languages, install_gadget.py will:

• Download the relevant debug adapter at a version that's been tested from the internet, either as a 'vsix' (Visusal Studio plugin), or clone from GitHub. If you're in a corporate environment and this is a problem, you may need to install the gadgets manually.
• Perform any necessary post-installation actions, such as:
  • Building any binary components
  • Ensuring scripts are executable, because the VSIX pacakges are usually broken in this regard.
  • Set up the gadgetDir symlinks for the platform.

To install the tested debug adapter for a language, run:

./install_gadget.py --enable-<language>

Or to install all supported gagtets:

./install_gadget.py --all

To install everything other than TCL (because TCL is sadly not as popular as it should be):

./install_gadget.py --all --disable-tcl

See --help for more info.

Manual gadget installation

You essentially need to get a working installation of the debug adapter, find out how to start it, and configure that in an adapters entry in either your .vimspector.json or in .gadgets.json.

The simplest way in practice is to install or start Visusal Studio Code and use its extension manager to install the relevant extension. You can then configure the adapter manually in the adapters section of your .vimspector.json or in a gagets.json.

PRs are always welcome to add configuration to do this to install_gadget.py.

The gadget directory

Vimspector uses the following directory by default to look for a file named .gadgets.json: </path/to/vimspector>/gadgets/<os>.

This path is exposed as the vimspector variable ${gadgetDir}. This is useful for configuring gadget command lines.

Where os is one of:

• macos
• linux
• windows (though note: Windows is not supported)

The format is the same as .vimspector.json, but only the gagets key is used:

Example:

{
  "adapters": {
    "vscode-cpptools": {
      "attach": {
        "pidProperty": "processId", 
        "pidSelect": "ask"
      }, 
      "command": [
        "${gadgetDir}/vscode-cpptools/debugAdapters/OpenDebugAD7"
      ], 
      "name": "cppdbg"
    }, 
    "vscode-python": {
      "command": [
        "node", 
        "${gadgetDir}/vscode-python/out/client/debugger/debugAdapter/main.js"
      ], 
      "name": "vscode-python"
    }
  }
}

The gadget file is automatically written by install_gadget.py.

About

Background

The motivation is that debugging in Vim is a pretty horrible experience, particularly if you use multiple languages. With pyclewn no more and the built-in termdebug plugin limited to gdb, I wanted to explore options.

While Language Server Protocol is well known, the Debug Adapter Protocol is less well known, but achieves a similar goal: language agnostic API abstracting debuggers from clients.

The aim of this project is to provide a simple but effective debugging experience in Vim for multiple languages, by leveraging the debug adapters that are being built for Visual Studio Code.

The ability to do remote debugging is a must. This is key to my workflow, so baking it in to the debugging experience is a top bill goal for the project. So vimspector has first-class support for executing programs remotely and attaching to them. This support is unique to vimspector and on top of (complementary to) any such support in actual debug adapters.

Status

Vimspector is a work in progress, and any feedback/contributions are more than welcome.

The backlog can be viewed on Trello.

In order to use it you have to currently:

• Write a mostly undocumented configuration file that contains essentially undocumented parameters.
• Accept that it isn't complete yet
• Work around some frustrating bugs in Vim
• Ignore probably many bugs in vimspector!

Experimental

The plugin is currently experimental. That means that any part of it can (and probably will) change, including things like:

• breaking changes to the configuration
• keys, layout, functionatlity of the UI

If a large number of people start using it then I will do my best to minimise this, or at least announce on Gitter.

Mappings

By default, vimspector does not change any of your mappings. Mappings are very personal and so you should work out what you like and use vim's powerful mapping features to set your own mappings. For example, if you want <F5> to start/continue debugging, add this to some appropriate place, such as your vimrc (hint: run :e $MYVIMRC).

nnoremap <F5> :call vimspector#Continue()<CR>

That said, many people are familiar with particular debuggers, so the following mappings can be enabled by setting g:vimspector_enable_mappings to the specified value.

Please note: Currently there are no <plug> mappings. These will be added in future to make custom mappings much easier.

Visual Studio / VSCode

To use Visual Studio-like mappings, add the following to your vimrc before loading vimspector:

let g:vimspector_enable_mappings = 'VISUAL_STUDIO'

Key	Function	API
F5	When debugging, continue. Otherwise start debugging.	vimspector#Continue()
Shift F5	Stop debugging.	vimspector#Stop()
Ctrl Shift F5	Restart debugging with the same configuration.	vimspector#Restart()
F6	Pause debugee.	vimspector#Pause()
F9	Toggle line breakpoint on the current line.	vimspector#ToggleBreakpoint()
Shift F9	Add a function breakpoint for the expression under cursor	vimspector#AddFunctionBreakpoint( '<cexpr>' )
F10	Step Over	vimspector#StepOver()
F11	Step Into	vimspector#StepInto()
Shift F11	Step out of current function scope	vimspector#StepOut()

Human Mode

If, like me, you only have 2 hands and 10 fingers, you probably don't like Ctrl-Shift-F keys. Also, if you're running in a terminal, there's a real possibility of terminfo being wrong for shifted-F-keys, particularly if your TERM is screen-256color. If these issues (number of hands, TERM variables) are unfixable, try the following mappings, by adding the following before loading vimspector:

let g:vimspector_enable_mappings = 'HUMAN'

Key	Function	API
F5	When debugging, continue. Otherwise start debugging.	vimspector#Continue()
F3	Stop debugging.	vimspector#Stop()
F4	Restart debugging with the same configuration.	vimspector#Restart()
F6	Pause debugee.	vimspector#Pause()
F9	Toggle line breakpoint on the current line.	vimspector#ToggleBreakpoint()
F8	Add a function breakpoint for the expression under cursor	vimspector#AddFunctionBreakpoint( '<cexpr>' )
F10	Step Over	vimspector#StepOver()
F11	Step Into	vimspector#StepInto()
F12	Step out of current function scope	vimspector#StepOut()

Usage

Launch and attach by PID:

• Create vimspector.json. See below.
• :call vimspector#Launch() and select a configuration.

Breakpoints

• Use vimspector#ToggleBreakpoint() to set/disable/delete a line breakpoint.
• Use vimspector#AddFunctionBreakpoint( '<name>' ) to add a function breakpoint.

Stepping

• Step in/out, finish, continue, pause etc. using the WinBar.
• If you really want to, the API is vimspector#StepInto() etc.

Variables and scopes

• Current scope shows values of locals.
• Use <CR> to expand/collapse (+, -).
• When changing the stack frame the locals window updates.
• While paused, hover to see values

Watches

The watches window is a prompt buffer. Enter insert mode to add a new watch expression.

• Add watches to the variables window by entering insert mode and typing the expression. Commit with <CR>.
• Expand result with <CR>.
• Delete with <DEL>.

Stack Traces

• In the threads window, use <CR> to expand/collapse.
• Use <CR> on a stack frame to jump to it.

Program Output:

• In the outputs window use the WinBar to select the output channel.
• The debugee prints to the stdout channel.
• Other channels may be useful for debugging.

Console

The console window is a prompt buffer and can be used as an interactive CLI for the debug adapter. Support for this varies amongt adapters.

• Enter insert mode to enter a command to evaluate
• Commit the request with <CR>
• The request and subsequent result are printed.

NOTE: See also [Watches][#watches] above.

Debug adapter configuration

Supported Languages

For more information on the configuration of .vimspector.json, take a look at the Getting Started section of the Vimspector website.

Current tested with the following debug adapters.

• C++: vscode-cpptools

Example .vimspector.json

{
  "configurations": {
    "<name>: Launch": {
      "adapter": "vscode-cpptools",
      "configuration": {
        "name": "<name>",
        "type": "cppdbg",
        "request": "launch",
        "program": "<path to binary>",
        "args": [ ... ],
        "cwd": "<working directory>",
        "environment": [ ... ],
        "externalConsole": true,
        "MIMode": "lldb"
      }
    },
    "<name>: Attach": {
      "adapter": "vscode-cpptools",
      "configuration": {
        "name": "<name>: Attach",
        "type": "cppdbg",
        "request": "attach",
        "program": "<path to binary>",
        "MIMode": "lldb"
      }
    }
    ...
  }
}

• Python: vscode-python

{
  "configurations": {
    "<name>: Launch": {
      "adapter": "vscode-python",
      "configuration": {
        "name": "<name>: Launch",
        "type": "python",
        "request": "launch",
        "cwd": "<working directory>",
        "stopOnEntry": true,
        "console": "externalTerminal",
        "debugOptions": [],
        "program": "<path to main python file>"
      }
    }
    ...
  }
}

• TCL (TclProDebug)

See my fork of TclProDebug for instructions.

• C# - dotnet core

Requires install_gadget.py --force-enable-c-sharp

{
  "configurations": {
    "launch - netcoredbg": {
      "adapter": "netcoredbg",
      "configuration": {
        "request": "launch",
        "program": "${workspaceRoot}/bin/Debug/netcoreapp2.2/csharp.dll",
        "args": [],
        "stopAtEntry": true
      }
    }
  }
}

• C# - mono

Requires install_gadget.py --force-enable-c-sharp.

Known not to work.*

{
  "configurations": {
    "launch - mono": {
      "adapter": "vscode-mono-debug",
      "configuration": {
        "request": "launch",
        "program": "${workspaceRoot}/bin/Debug/netcoreapp2.2/csharp.dll",
        "args": [],
        "cwd": "${workspaceRoot}",
        "runtimeExecutable": "mono",
        "runtimeArgs": [],
        "env": [],
        "externalConsole": false,
        "console": "integratedTerminal"
      }
    }
  }
}

• Go

Requires:

• install_gadget.py --enable-go
• Delve installed, e.g. go get -u github.com/go-delve/delve/cmd/dlv
• Delve to be in your PATH, or specify the dlvToolPath launch option

{
  "configurations": {
    "run": {
      "adapter": "vscode-go",
      "configuration": {
        "request": "launch",
        "program": "${fileDirname}",
        "mode": "debug",
        "dlvToolPath": "$HOME/go/bin/dlv"
      }
    }
  }
}

• Node.js

Requires:

• install_gadget.py --force-enable-node
• For installation, a Node.js environemt that is < node 12. I believe this is an incompatibility with gulp. Advice, use [nvm][] with nvm install --lts 10; nvm use --lts 10; ./install_gadget.py --force-enable-node ...
• Options described here: https://code.visualstudio.com/docs/nodejs/nodejs-debugging
• Example: support/test/node/simple

{
  "configurations": {
    "run": {
      "adapter": "vscode-node",
      "configuration": {
        "request": "launch",
        "protocol": "auto",
        "stopOnEntry": true,
        "console": "integratedTerminal",
        "program": "${workspaceRoot}/simple.js",
        "cwd": "${workspaceRoot}"
      }
    }
  }
}

• Chrome

This uses the chrome debugger, see https://marketplace.visualstudio.com/items?itemName=msjsdiag.debugger-for-chrome.

It allows you to debug scripts running inside chrome from within Vim.

• ./install_gadget.py --force-enable-chrome
• Example: support/test/chrome

{
  "configurations": {
    "launch": {
      "adapter": "chrome",
      "configuration": {
        "request": "launch",
        "url": "http://localhost:1234/",
        "webRoot": "${workspaceRoot}/www"
      }
    }
  }
}

Also the mock debugger, but that isn't actually useful.

Partially supported

• Java Debug Server. The java debug server runs as a jdt.ls plugin, rather than a standalone debug adapter. This makes a lot of sense if you already happen to be running the language server. Vimspector is not in the business of running language servers. So, rather than doing so, vimspector simply allows you to start the java debug server manually (however you might do so) and you can tell vimspector the port on which it is listening. See this issue for more background.

FAQ

1. Q: Does it work? A: Yeah, sort of. It's incredibly buggy and unpolished.
2. Q: Does it work with this language? A: Probably, but it won't necessarily be easy to work out what to put in the .vimspector.json. As you can see above, some of the servers aren't really editor agnostic, and require very-specific unique handling.

License

Apache 2.0

Copyright © 2018 Ben Jackson