Coverage data is not automatically loaded when running Coverage* commands

[lukepafford]

Description

First off, pretty damn nifty plugin. I Just started ramping up with NeoVim, and I try to create a "toggle" mapping for every plugin that contains its own "on/off" actions.

If I want to turn on the coverage report in my code files, I have to first run CoverageLoad, and then run CoverageToggle. This is two commands, rather than one. Ok, not the end of the world, let's just map these two commands to a single mapping:

keys = {
  { "<leader>cot", 
    function()
      local cov = require("coverage")
      cov.load()
      cov.toggle()
    end, desc = "Coverage Toggle"
  },
}

Unfortunately, this doesn't work. I suspect the reason is because CoverageLoad is performing IO, and CoverageToggle finishes running before CoverageLoad completes. I have created a workaround that waits half a second, and produces consistent results:

-- My hacky-ish nvim-coverage.lua config for lazy.nvim
local function waitUntilLoaded()
    local coverageLoaded = false

    return function(cov, f)
        if not coverageLoaded then
            cov.load()
            coverageLoaded = true

            local timer = vim.loop.new_timer()
            timer:start(500, 0, function()
                vim.schedule(function()
                    f()
                end)
            end
            )
        else
            f()
        end
    end
end


WaitUntilLoaded = waitUntilLoaded()

local function toggle(cov)
    return WaitUntilLoaded(cov, cov.toggle)
end

local function summary(cov)
    return WaitUntilLoaded(cov, cov.summary)
end

return {
    "andythigpen/nvim-coverage",
    lazy = true,
    dependencies = {
        'nvim-lua/plenary.nvim',
        'nvim-neotest/neotest',
    },
    keys = {
        { "<leader>cos", function() local cov = require("coverage") summary(cov) end, desc = "Coverage Summary" },
        { "<leader>cot", function() local cov = require("coverage") toggle(cov) end, desc = "Coverage Toggle"},
    },
    config = function()
        require("coverage").setup({
            auto_reload = true,
        })
    end
}

While this works for me, this feels like something that nvim-coverage should do natively, and with a less hacky solution than just sleeping for half a second.

You would probably want to emit an event when CoverageLoad completes, and Coverage* commands would listen for that event (I don't know how this is done in the NeoVim API, I'm just a newborn lua scripter 🥲)

Acceptance Criteria

• nvim-coverage automatically loads coverage data when performing Coverage commands for the first time

[andythigpen]

does the following work for your use case?

keys = {
  { "<leader>cot", 
    function()
      local cov = require("coverage")
      cov.load(true)
    end, desc = "Coverage Toggle"
  },
}

passing true to the load function will place the signs after they are loaded

[lukepafford]

Unfortunately that is still a bit buggy. Here is my revised config:

Revised Buggy Config

return {
    "andythigpen/nvim-coverage",
    lazy = true,
    dependencies = {
        'nvim-lua/plenary.nvim',
        'nvim-neotest/neotest',
    },
    keys = {
        {
            "<leader>cos",
            function()
                local cov = require("coverage")
                cov.load()
                cov.summary()
            end,
            desc = "Coverage Summary"
        },
        {
            "<leader>cot",
            function()
                local cov = require("coverage")
                cov.load(true)
            end,
            desc = "Coverage Toggle"
        },
        -- { "<leader>cos", function() local cov = require("coverage") summary(cov) end, desc = "Coverage Summary" },
        -- { "<leader>cot", function() local cov = require("coverage") toggle(cov) end, desc = "Coverage Toggle"},
    },
    config = function()
        local cov = require("coverage").setup({
            auto_reload = true
        })
    end
}

Toggle Issues

Running <leader>cot will turn the coverage on with this configuration, however re-running the toggle command doesn't turn it off.

Summary Issues

Running <leader>cos will fail on the first attempt with the error "Coverage report not loaded", and then works after the 2nd+ attempts. I assume this is the case because the first load command is running asynchronously and hasn't completed yet.

---

My current config in the original post is still working fine for me, so this isn't super important, it just seems unintuitive for new plugin users.

[l1nd3r0th]

Hi,

If it's of help to anyone, I did something like this:

local coverage = require("coverage")

local show_coverage = false

function toggle_coverage(ev)
  show_coverage = not show_coverage
  coverage.load(show_coverage)
end

local function load_cb()
  if show_coverage then
    coverage.show()
  else
    coverage.hide()
  end
end

-- Setup coverage
coverage.setup({
  auto_reload = true,
  load_coverage_cb = load_cb,
})

-- Auto-load for python
vim.api.nvim_create_autocmd('FileType', {
  pattern = 'python',
  desc = 'Auto-load coverage in python projects',
  callback = coverage.load,
})

And in my keymap file:

local keymap = vim.api.nvim_set_keymap

-- Coverage
keymap('n', '<leader>cs', ':CoverageSummary<CR>', { noremap = true })
keymap('n', '<leader>cv', '', { noremap = true, callback = toggle_coverage })

It works well for my purposes.

• When I open a python file .coverage is auto-loaded, but not displayed in the signcolumn
• <leader>cv toggles display (and reloads .coverage, technically)
• When I re-run the testsuite, the signs update, if they are visible (and they stay visible/hidden)

---

@andythigpen Thanks for the nice plugin! :ok_hand: