feat: allow rendering when window is in diff mode

## Details

Request: #645

Previously all rendering was disabled in diff mode as there was no use
case for it: 01b38dc

Now there is, add a new `render.diff` option that when set to `true`
allows rendering to proceed when it otherwise would not.

Author: MeanderingProgrammer

README.md

@@ -691,6 +691,10 @@ require('render-markdown').setup({
             'RenderMarkdownQuote6',
         },
     },
+    render = {
+        -- Whether to render when window is in diff-mode.
+        diff = false,
+    },
     pipe_table = {
         -- Turn on / off pipe table rendering.
         enabled = true,

doc/render-markdown.txt

@@ -758,6 +758,10 @@ Default Configuration ~
                 'RenderMarkdownQuote6',
             },
         },
+        render = {
+            -- Whether to render when window is in diff-mode.
+            diff = false,
+        },
         pipe_table = {
             -- Turn on / off pipe table rendering.
             enabled = true,

lua/render-markdown/core/ui.lua

@@ -98,7 +98,7 @@ function Updater:run()
     local render = self.config.enabled
         and self.config.resolved:render(self.mode)
         and env.win.view(self.win).leftcol == 0
-        and not env.win.get(self.win, 'diff')
+        and (self.config.render.diff or not env.win.get(self.win, 'diff'))
     log.buf('info', 'Render', self.buf, render)
     local next_state = render and 'rendered' or 'default'
     for _, win in ipairs(env.buf.wins(self.buf)) do

lua/render-markdown/health.lua

@@ -6,7 +6,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '8.12.14'
+M.version = '8.12.15'
 
 function M.check()
     M.start('versions')

lua/render-markdown/init.lua

@@ -26,6 +26,7 @@ local M = {}
 ---@field paragraph render.md.paragraph.Config
 ---@field pipe_table render.md.table.Config
 ---@field quote render.md.quote.Config
+---@field render render.md.render.Config
 ---@field sign render.md.sign.Config
 ---@field win_options render.md.window.Configs
 ---@field yaml render.md.yaml.Config
@@ -105,6 +106,7 @@ M.default = {
     bullet = settings.bullet.default,
     checkbox = settings.checkbox.default,
     quote = settings.quote.default,
+    render = settings.render.default,
     pipe_table = settings.pipe_table.default,
     callout = settings.callout.default,
     link = settings.link.default,

lua/render-markdown/lib/config.lua

@@ -36,6 +36,7 @@ function Config.new(root, enabled, buf, custom)
         paragraph = root.paragraph,
         pipe_table = root.pipe_table,
         quote = root.quote,
+        render = root.render,
         sign = root.sign,
         win_options = root.win_options,
         yaml = root.yaml,
@@ -118,6 +119,7 @@ function Config.schema(child)
         paragraph = settings.paragraph.schema(),
         pipe_table = settings.pipe_table.schema(),
         quote = settings.quote.schema(),
+        render = settings.render.schema(),
         sign = settings.sign.schema(),
         win_options = settings.win_options.schema(),
         yaml = settings.yaml.schema(),

lua/render-markdown/settings.lua

@@ -1785,6 +1785,28 @@ function M.quote.schema()
     })
 end
 
+---@class render.md.render.Settings
+M.render = {}
+
+---@class (exact) render.md.render.Config
+---@field diff boolean
+
+---@type render.md.render.Config
+M.render.default = {
+    -- Whether to render when window is in diff-mode.
+    diff = false,
+}
+
+---@return render.md.Schema
+function M.render.schema()
+    ---@type render.md.Schema
+    return {
+        record = {
+            diff = { type = 'boolean' },
+        },
+    }
+end
+
 ---@class render.md.sign.Settings
 M.sign = {}
 

lua/render-markdown/types.lua

@@ -23,6 +23,7 @@
 ---@field paragraph? render.md.paragraph.UserConfig
 ---@field pipe_table? render.md.table.UserConfig
 ---@field quote? render.md.quote.UserConfig
+---@field render? render.md.render.UserConfig
 ---@field sign? render.md.sign.UserConfig
 ---@field win_options? render.md.window.UserConfigs
 ---@field yaml? render.md.yaml.UserConfig
@@ -299,6 +300,9 @@
 ---@field repeat_linebreak? boolean
 ---@field highlight? string|string[]
 
+---@class (exact) render.md.render.UserConfig
+---@field diff? boolean
+
 ---@class (exact) render.md.sign.UserConfig
 ---@field enabled? boolean
 ---@field priority? integer