I cannot figure out how to make my diagnostics flexible

[unphased]

Here’s the component

local Diagnostics = {

    condition = conditions.has_diagnostics,

    static = {
        -- error_icon = vim.fn.sign_getdefined("DiagnosticSignError")[1].text,
        -- warn_icon = vim.fn.sign_getdefined("DiagnosticSignWarn")[1].text,
        -- info_icon = vim.fn.sign_getdefined("DiagnosticSignInfo")[1].text,
        -- hint_icon = vim.fn.sign_getdefined("DiagnosticSignHint")[1].text,
        error_icon = "✘ ",
        warn_icon = "▲ ",
        info_icon = " ",
        hint_icon = "⚑ ",
    },

    init = function(self)
        self.errors = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.ERROR })
        self.warnings = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.WARN })
        self.hints = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.HINT })
        self.info = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.INFO })
    end,

    update = { "DiagnosticChanged", "BufEnter" },

    -- {
    --     provider = "![",
    -- },
    flexible = 20,
    {
        {
            provider = function(self)
                -- 0 is just another output, we can decide to print it or not!
                return self.errors > 0 and (self.error_icon .. self.errors .. " ")
            end,
            hl = { fg = "diag_error" },
        },
        {
            provider = function(self)
                return self.warnings > 0 and (self.warn_icon .. self.warnings .. " ")
            end,
            hl = { fg = "diag_warn" },
        },
        {
            provider = function(self)
                return self.info > 0 and (self.info_icon .. self.info .. " ")
            end,
            hl = { fg = "diag_info" },
        },
        {
            provider = function(self)
                return self.hints > 0 and (self.hint_icon .. self.hints)
            end,
            hl = { fg = "diag_hint" },
        },
    },
    {
        {
            provider = function(self)
                -- 0 is just another output, we can decide to print it or not!
                return self.errors > 0 and (self.error_icon .. self.errors .. " ")
            end,
            hl = { fg = "diag_error" },
        },
        {
            provider = function(self)
                return self.warnings > 0 and (self.warn_icon .. self.warnings .. " ")
            end,
            hl = { fg = "diag_warn" },
        },
        {
            provider = function(self)
                return self.info > 0 and (self.info_icon .. self.info .. " ")
            end,
            hl = { fg = "diag_info" },
        },
    },
    {
        {
            provider = function(self)
                -- 0 is just another output, we can decide to print it or not!
                return self.errors > 0 and (self.error_icon .. self.errors .. " ")
            end,
            hl = { fg = "diag_error" },
        },
        {
            provider = function(self)
                return self.warnings > 0 and (self.warn_icon .. self.warnings .. " ")
            end,
            hl = { fg = "diag_warn" },
        },
    },
    {
        {
            provider = function(self)
                -- 0 is just another output, we can decide to print it or not!
                return self.errors > 0 and (self.error_icon .. self.errors .. " ")
            end,
            hl = { fg = "diag_error" },
        },

    }
    -- {
    --     provider = "]",
    -- },
}

The behavior I observe is that this does not become flexible at all and is always shown.

[rebelot]

Try removing the update field

[unphased]

Great, it works! I also reckon that the experience will not be noticeably degraded by not having these update events trigger the re-render. Maybe they won't be fully up to date at all times, but once the cursor moves it will update.

[rebelot]

You can put the update field inside the flexible children. If the parent (the flexible component) is behind an update autocmd it won't trigger the routine that handles the resize

[unphased]

Perfect, thank you for that clarification! So I take it then that we actually want to specify the update fields where applicable as they serve to reduce unnecessary re-renders of components rather than adding more?

[rebelot]

Exactly. Statusline is always re evaluated a bunch of times, update field is mostly there for performance to allow components to be re evaluated only on certain conditions. However, it might be useful also for triggering a redraw on certain events where the statusline is not redrawn, such as entering operator pending mode, or start recording a macro. There's a few examples in the cookbook about that, where you can add redrawstatus within the callback