fix: more robust icon provider resolution

## Details

Issue: #403

The `get` call into `mini.icons` can sometimes be `nil`, while I'm
unable to replicate it we can definitely make this module more robust
by adding more checks than a `pcall` around `require`.

To fix this the logic has been entirely re-written. In addition to
`pcall` we now also:

- validate the required module is not `nil`
- validate that the method we use for the provider is not `nil`
- validate `_G.MiniIcons ~= nil` as specified in the docs

Minor other changes:

- pull `default` configuration directly in state module where needed
- add an `alias` for `dash` width type
- consistently call cache tables  `Cache` and use `class` annotation
- `render.md.BufferConfig` -> `render.md.main.Config`
- directly invalidate state cache in `init` module

Author: MeanderingProgrammer

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*           For 0.11.0          Last change: 2025 April 17
+*render-markdown.txt*           For 0.11.0          Last change: 2025 April 21
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*

lua/render-markdown/api.lua

@@ -54,8 +54,7 @@ function M.debug()
 end
 
 function M.config()
-    local markdown = require('render-markdown')
-    local difference = state.difference(markdown.default)
+    local difference = state.difference()
     if vim.tbl_count(difference) == 0 then
         vim.print('Default Configuration')
     else

lua/render-markdown/colors.lua

@@ -1,4 +1,4 @@
----@class render.md.cache.Colors
+---@class render.md.colors.Cache
 ---@field combine table<string, { fg: string, bg: string }>
 ---@field bg_to_fg table<string, { hl: string }>
 local Cache = {

lua/render-markdown/config.lua

@@ -1,18 +1,18 @@
 local Env = require('render-markdown.lib.env')
 local Range = require('render-markdown.core.range')
 
----@class render.md.Components
+---@class render.md.main.Components
 ---@field callout table<string, render.md.callout.Config>
 ---@field checkbox table<string, render.md.checkbox.custom.Config>
 
----@class render.md.BufferConfig: render.md.buffer.Config
+---@class render.md.main.Config: render.md.buffer.Config
 ---@field private modes render.md.Modes
----@field private components render.md.Components
+---@field private components render.md.main.Components
 local Config = {}
 Config.__index = Config
 
 ---@param config render.md.buffer.Config
----@return render.md.BufferConfig
+---@return render.md.main.Config
 function Config.new(config)
     -- Super set of render modes across top level and individual components
     local modes = config.render_modes
@@ -22,7 +22,7 @@ function Config.new(config)
         end
     end
 
-    ---@type render.md.Components
+    ---@type render.md.main.Components
     local components = {
         callout = Config.normalize(config.callout),
         checkbox = Config.normalize(config.checkbox.custom),
@@ -119,19 +119,17 @@ end
 ---@param row? integer
 ---@return render.md.Range?
 function Config:hidden(mode, row)
-    -- Anti-conceal is not enabled -> hide nothing
-    -- Row is not known -> buffer is not active -> hide nothing
-    if not self.anti_conceal.enabled or row == nil then
+    -- anti-conceal is not enabled -> hide nothing
+    -- row is not known -> buffer is not active -> hide nothing
+    local config = self.anti_conceal
+    if not config.enabled or row == nil then
         return nil
     end
     if vim.tbl_contains({ 'v', 'V', '\22' }, mode) then
         local start = vim.fn.getpos('v')[2] - 1
         return Range.new(math.min(row, start), math.max(row, start))
     else
-        return Range.new(
-            row - self.anti_conceal.above,
-            row + self.anti_conceal.below
-        )
+        return Range.new(row - config.above, row + config.below)
     end
 end
 

lua/render-markdown/config/dash.lua

@@ -1,9 +1,11 @@
 ---@class (exact) render.md.dash.Config: render.md.base.Config
 ---@field icon string
----@field width 'full'|number
+---@field width render.md.dash.Width
 ---@field left_margin number
 ---@field highlight string
 
+---@alias render.md.dash.Width 'full'|number
+
 local M = {}
 
 ---@param spec render.md.debug.ValidatorSpec

lua/render-markdown/core/context.lua

@@ -220,29 +220,29 @@ function Context:for_each(callback)
     return false
 end
 
----@type table<integer, render.md.Context>
-local cache = {}
+---@class render.md.context.Cache: { [integer]: render.md.Context }
+local Cache = {}
 
----@class render.md.ContextManager
+---@class render.md.context.Manager
 local M = {}
 
 ---@param props render.md.context.Props
 function M.reset(props)
-    cache[props.buf] = Context.new(props, 10)
+    Cache[props.buf] = Context.new(props, 10)
 end
 
 ---@param buf integer
 ---@param win integer
 ---@return boolean
 function M.contains_range(buf, win)
-    local context = cache[buf]
+    local context = Cache[buf]
     return context ~= nil and context:contains_window(win)
 end
 
 ---@param buf integer
 ---@return render.md.Context
 function M.get(buf)
-    return cache[buf]
+    return Cache[buf]
 end
 
 return M

lua/render-markdown/core/log.lua

@@ -12,6 +12,7 @@ local Env = require('render-markdown.lib.env')
 ---@field private file string
 local M = {}
 
+---Should only be called from state on setup
 ---@param level render.md.config.LogLevel
 function M.setup(level)
     -- Write out any logs before closing

lua/render-markdown/core/ui.lua

@@ -23,7 +23,7 @@ local builtin_handlers = {
     markdown_inline = require('render-markdown.handler.markdown_inline'),
 }
 
----@class render.md.cache.Ui
+---@class render.md.ui.Cache
 ---@field states table<integer, render.md.Buffer>
 local Cache = {
     states = {},
@@ -97,7 +97,8 @@ function M.update(buf, win, event, change)
     end
 
     local parse = M.parse(buf, win, change)
-    local config, buffer = state.get(buf), Cache.get(buf)
+    local config = state.get(buf)
+    local buffer = Cache.get(buf)
     if buffer:is_empty() then
         return
     end
@@ -181,7 +182,7 @@ function M.run_update(buf, win, change)
 end
 
 ---@private
----@param config render.md.BufferConfig
+---@param config render.md.main.Config
 ---@param win integer
 ---@param mode string
 ---@return 'default'|'rendered'

lua/render-markdown/handler/html.lua

@@ -4,7 +4,7 @@ local state = require('render-markdown.state')
 local ts = require('render-markdown.integ.ts')
 
 ---@class render.md.handler.buf.Html
----@field private config render.md.BufferConfig
+---@field private config render.md.main.Config
 ---@field private context render.md.Context
 ---@field private marks render.md.Marks
 ---@field private query vim.treesitter.Query

lua/render-markdown/handler/latex.lua

@@ -6,8 +6,8 @@ local Str = require('render-markdown.lib.str')
 local log = require('render-markdown.core.log')
 local state = require('render-markdown.state')
 
----@type table<string, string>
-local cache = {}
+---@class render.md.latex.Cache: { [string]: string }
+local Cache = {}
 
 ---@class render.md.handler.Latex: render.md.Handler
 local M = {}
@@ -27,14 +27,14 @@ function M.parse(ctx)
     local node = Node.new(ctx.buf, ctx.root)
     log.node('latex', node)
 
-    local raw_expression = cache[node.text]
+    local raw_expression = Cache[node.text]
     if raw_expression == nil then
         raw_expression = vim.fn.system(latex.converter, node.text)
         if vim.v.shell_error == 1 then
             log.add('error', latex.converter, raw_expression)
             raw_expression = 'error'
         end
-        cache[node.text] = raw_expression
+        Cache[node.text] = raw_expression
     end
 
     local expressions = {} ---@type string[]