feat: drop source groups in favor of fallback_for (#83)

Author: Saghen

README.md

@@ -227,48 +227,51 @@ MiniDeps.add({
     -- returns no completion items
     -- WARN: This API will have breaking changes during the beta
     providers = {
-      {
-        { 'blink.cmp.sources.lsp' },
-        { 'blink.cmp.sources.path' },
-        { 'blink.cmp.sources.snippets', score_offset = -3 },
-      },
-      { { 'blink.cmp.sources.buffer' } },
+      { 'blink.cmp.sources.lsp', name = 'LSP' },
+      { 'blink.cmp.sources.path', name = 'Path', score_offset = 3 },
+      { 'blink.cmp.sources.snippets', score_offset = -3 },
+      { 'blink.cmp.sources.buffer', name = 'Buffer', fallback_for = { 'LSP' } },
     },
     -- FOR REF: full example
     providers = {
+      -- all of these properties work on every source
+      {
+          'blink.cmp.sources.lsp',
+          name = 'LSP',
+          keyword_length = 0,
+          score_offset = 0,
+          trigger_characters = { 'f', 'o', 'o' },
+      }, 
+      -- the following two sources have additional options
       { 
-        -- all of these properties work on every source
-        {
-            'blink.cmp.sources.lsp',
-            keyword_length = 0,
-            score_offset = 0,
-            trigger_characters = { 'f', 'o', 'o' },
-            opts = {},
-        }, 
-        -- the follow two sources have additional options
-        { 
-          'blink.cmp.sources.path', 
-          opts = {
-            trailing_slash = false,
-            label_trailing_slash = true,
-            get_cwd = function(context) return vim.fn.expand(('#%d:p:h'):format(context.bufnr)) end,
-            show_hidden_files_by_default = true,
-          }
-        },
-        {
-          'blink.cmp.sources.snippets',
-          score_offset = -3,
-          -- similar to https://github.com/garymjr/nvim-snippets
-          opts = {
-            friendly_snippets = true,
-            search_paths = { vim.fn.stdpath('config') .. '/snippets' },
-            global_snippets = { 'all' },
-            extended_filetypes = {},
-            ignored_filetypes = {},
-          },
+        'blink.cmp.sources.path', 
+        name = 'Path',
+        score_offset = 3,
+        opts = {
+          trailing_slash = false,
+          label_trailing_slash = true,
+          get_cwd = function(context) return vim.fn.expand(('#%d:p:h'):format(context.bufnr)) end,
+          show_hidden_files_by_default = true,
+        }
+      },
+      {
+        'blink.cmp.sources.snippets',
+        name = 'Snippets',
+        score_offset = -3,
+        -- similar to https://github.com/garymjr/nvim-snippets
+        opts = {
+          friendly_snippets = true,
+          search_paths = { vim.fn.stdpath('config') .. '/snippets' },
+          global_snippets = { 'all' },
+          extended_filetypes = {},
+          ignored_filetypes = {},
         },
       },
-      { { 'blink.cmp.sources.buffer' } }
+      { 
+        'blink.cmp.sources.buffer',
+        name = 'Buffer',
+        fallback_for = { 'LSP' },
+      }
     }
   },
 

lua/blink/cmp/config.lua

@@ -47,10 +47,12 @@
 --- @field signature_help? blink.cmp.SignatureHelpTriggerConfig
 
 --- @class blink.cmp.SourceConfig
---- @field providers? blink.cmp.SourceProviderConfig[][]
+--- @field providers? blink.cmp.SourceProviderConfig[]
 ---
 --- @class blink.cmp.SourceProviderConfig
 --- @field [1]? string
+--- @field name string
+--- @field fallback_for? string[] | nil
 --- @field keyword_length? number | nil
 --- @field score_offset? number | nil
 --- @field deduplicate? blink.cmp.DeduplicateConfig | nil
@@ -228,12 +230,10 @@ local config = {
     -- returns no completion items
     -- WARN: This API will have breaking changes during the beta
     providers = {
-      {
-        { 'blink.cmp.sources.lsp' },
-        { 'blink.cmp.sources.path' },
-        { 'blink.cmp.sources.snippets', score_offset = -2 },
-      },
-      { { 'blink.cmp.sources.buffer' } },
+      { 'blink.cmp.sources.lsp', name = 'LSP' },
+      { 'blink.cmp.sources.path', name = 'Path', score_offset = 3 },
+      { 'blink.cmp.sources.snippets', name = 'Snippets', score_offset = -3 },
+      { 'blink.cmp.sources.buffer', name = 'Buffer', fallback_for = { 'LSP' } },
     },
   },
 

lua/blink/cmp/sources/lib/async.lua

@@ -7,8 +7,8 @@
 --- @field new fun(fn: fun(resolve: fun(result: any), reject: fun(err: any))): blink.cmp.Task
 ---
 --- @field cancel fun(self: blink.cmp.Task)
---- @field map fun(self: blink.cmp.Task, fn: fun(result: any): blink.cmp.Task | any)
---- @field catch fun(self: blink.cmp.Task, fn: fun(err: any): blink.cmp.Task | any)
+--- @field map fun(self: blink.cmp.Task, fn: fun(result: any): blink.cmp.Task | any): blink.cmp.Task
+--- @field catch fun(self: blink.cmp.Task, fn: fun(err: any): blink.cmp.Task | any): blink.cmp.Task
 ---
 --- @field on_completion fun(self: blink.cmp.Task, cb: fun(result: any))
 --- @field on_failure fun(self: blink.cmp.Task, cb: fun(err: any))

lua/blink/cmp/sources/lib/context.lua

@@ -1,17 +1,17 @@
+local utils = require('blink.cmp.sources.lib.utils')
 local async = require('blink.cmp.sources.lib.async')
 local sources_context = {}
 
 --- @param context blink.cmp.Context
---- @param sources_groups blink.cmp.Source[][]
+--- @param sources blink.cmp.SourceProvider[]
 --- @param on_completions_callback fun(context: blink.cmp.Context, items: blink.cmp.CompletionItem[])
-function sources_context.new(context, sources_groups, on_completions_callback)
+function sources_context.new(context, sources, on_completions_callback)
   local self = setmetatable({}, { __index = sources_context })
   self.id = context.id
-  self.sources_groups = sources_groups
+  self.sources = sources
 
   self.active_request = nil
   self.queued_request_context = nil
-  self.last_sources_group_idx = nil
   --- @type fun(context: blink.cmp.Context, items: blink.cmp.CompletionItem[])
   self.on_completions_callback = on_completions_callback
 
@@ -27,26 +27,12 @@ function sources_context:get_completions(context)
     return
   end
 
-  -- Create a task to get the completions for the first sources group,
-  -- falling back to the next sources group iteratively if there are no items
-  local request = self:get_completions_for_group(1, self.sources_groups[1], context)
-  for idx, sources_group in ipairs(self.sources_groups) do
-    if idx > 1 then
-      request = request:map(function(res)
-        if #res.items > 0 then return res end
-        return self:get_completions_for_group(idx, sources_group, context)
-      end)
-    end
-  end
-
-  -- Send response upstream and run the queued request, if it exists
-  self.active_request = request:map(function(response)
+  -- Create a task to get the completions, send responses upstream
+  -- and run the queued request, if it exists
+  self.active_request = self:get_completions_for_sources(self.sources, context):map(function(response)
     self.active_request = nil
     -- only send upstream if the response contains something new
-    if not response.is_cached or response.sources_group_idx ~= self.last_sources_group_idx then
-      self.on_completions_callback(context, response.items)
-    end
-    self.last_sources_group_idx = response.sources_group_idx
+    if not response.is_cached then self.on_completions_callback(context, response.items) end
 
     -- run the queued request, if it exists
     if self.queued_request_context ~= nil then
@@ -57,28 +43,26 @@ function sources_context:get_completions(context)
   end)
 end
 
---- @param sources_group_idx number
---- @param sources_group blink.cmp.Source[]
+--- @param sources blink.cmp.SourceProvider[]
 --- @param context blink.cmp.Context
 --- @return blink.cmp.Task
-function sources_context:get_completions_for_group(sources_group_idx, sources_group, context)
-  -- get completions for each source in the group
+function sources_context:get_completions_for_sources(sources, context)
+  local non_fallback_sources = vim.tbl_filter(function(source) return source.config.fallback_for == nil end, sources)
+
+  -- get completions for each non-fallback source
   local tasks = vim.tbl_map(function(source)
     -- the source indicates we should refetch when this character is typed
     local trigger_character = context.trigger.character
       and vim.tbl_contains(source:get_trigger_characters(), context.trigger.character)
 
-    -- The TriggerForIncompleteCompletions kind is handled by the source itself
+    -- The TriggerForIncompleteCompletions kind is handled by the source provider itself
     local source_context = require('blink.cmp.utils').shallow_copy(context)
     source_context.trigger = trigger_character
         and { kind = vim.lsp.protocol.CompletionTriggerKind.TriggerCharacter, character = context.trigger.character }
       or { kind = vim.lsp.protocol.CompletionTriggerKind.Invoked }
 
-    return source:get_completions(source_context):catch(function(err)
-      vim.print(source.name .. ': failed to get completions with error: ' .. err)
-      return { is_incomplete_forward = false, is_incomplete_backward = false, items = {} }
-    end)
-  end, sources_group)
+    return self:get_completions_with_fallbacks(source_context, source, sources)
+  end, non_fallback_sources)
 
   -- wait for all the tasks to complete
   return async.task
@@ -91,21 +75,59 @@ function sources_context:get_completions_for_group(sources_group_idx, sources_gr
       for idx, task_result in ipairs(tasks_results) do
         if task_result.status == async.STATUS.COMPLETED then
           is_cached = is_cached and (task_result.result.is_cached or false)
-          local source = sources_group[idx]
+          local source = sources[idx]
           --- @type blink.cmp.CompletionResponse
           local response = task_result.result
           response.items = source:filter_completions(response)
           if source:should_show_completions(context, response) then vim.list_extend(items, response.items) end
         end
       end
-      return { sources_group_idx = sources_group_idx, is_cached = is_cached, items = items }
+      return { is_cached = is_cached, items = items }
     end)
     :catch(function(err)
-      vim.print('failed to get completions for group with error: ' .. err)
-      return { sources_group_idx = sources_group_idx, is_cached = false, items = {} }
+      vim.print('failed to get completions for sources with error: ' .. err)
+      return { is_cached = false, items = {} }
     end)
 end
 
+--- Runs the source's get_completions function, falling back to other sources
+--- with fallback_for = { source.name } if the source returns no completion items
+--- @param context blink.cmp.Context
+--- @param source blink.cmp.SourceProvider
+--- @param sources blink.cmp.SourceProvider[]
+--- @return blink.cmp.Task
+--- TODO: When a source has multiple fallbacks, we may end up with duplicate completion items
+function sources_context:get_completions_with_fallbacks(context, source, sources)
+  local fallback_sources = vim.tbl_filter(
+    function(fallback_source)
+      return fallback_source.name ~= source.name
+        and fallback_source.config.fallback_for ~= nil
+        and vim.tbl_contains(fallback_source.config.fallback_for, source.name)
+    end,
+    sources
+  )
+
+  return source:get_completions(context):map(function(response)
+    -- source returned completions, no need to fallback
+    if #response.items > 0 or #fallback_sources == 0 then return response end
+
+    -- run fallbacks
+    return async.task
+      .await_all(vim.tbl_map(function(fallback) return fallback:get_completions(context) end, fallback_sources))
+      :map(function(task_results)
+        local successful_task_results = vim.tbl_filter(
+          function(task_result) return task_result.status == async.STATUS.COMPLETED end,
+          task_results
+        )
+        local fallback_responses = vim.tbl_map(
+          function(task_result) return task_result.result end,
+          successful_task_results
+        )
+        return utils.concat_responses(fallback_responses)
+      end)
+  end)
+end
+
 function sources_context:destroy()
   self.on_completions_callback = function() end
   if self.active_request ~= nil then self.active_request:cancel() end

lua/blink/cmp/sources/lib/init.lua

@@ -3,19 +3,15 @@ local config = require('blink.cmp.config')
 local sources = {
   current_context = nil,
   sources_registered = false,
-  sources_groups = {},
+  providers = {},
   on_completions_callback = function(_, _) end,
 }
 
 function sources.register()
-  assert(#sources.sources_groups == 0, 'Sources have already been registered')
+  assert(#sources.providers == 0, 'Sources have already been registered')
 
-  for _, sources_group in ipairs(config.sources.providers) do
-    local group = {}
-    for _, source_config in ipairs(sources_group) do
-      table.insert(group, require('blink.cmp.sources.lib.source').new(source_config))
-    end
-    table.insert(sources.sources_groups, group)
+  for _, source_config in ipairs(config.sources.providers) do
+    table.insert(sources.providers, require('blink.cmp.sources.lib.provider').new(source_config))
   end
 end
 
@@ -29,8 +25,7 @@ function sources.get_trigger_characters()
   end
 
   local trigger_characters = {}
-  -- todo: should this be all source groups?
-  for _, source in pairs(sources.sources_groups[1]) do
+  for _, source in pairs(sources.providers) do
     local source_trigger_characters = source:get_trigger_characters()
     for _, char in ipairs(source_trigger_characters) do
       if not blocked_trigger_characters[char] then table.insert(trigger_characters, char) end
@@ -48,7 +43,7 @@ function sources.request_completions(context)
   if is_new_context then
     if sources.current_context ~= nil then sources.current_context:destroy() end
     sources.current_context =
-      require('blink.cmp.sources.lib.context').new(context, sources.sources_groups, sources.on_completions_callback)
+      require('blink.cmp.sources.lib.context').new(context, sources.providers, sources.on_completions_callback)
   end
 
   sources.current_context:get_completions(context)
@@ -68,14 +63,11 @@ end
 --- @return fun(): nil Cancelation function
 function sources.resolve(item, callback)
   local item_source = nil
-  for _, group in ipairs(sources.sources_groups) do
-    for _, source in ipairs(group) do
-      if source.name == item.source then
-        item_source = source
-        break
-      end
+  for _, source in ipairs(sources.providers) do
+    if source.name == item.source then
+      item_source = source
+      break
     end
-    if item_source ~= nil then break end
   end
 
   if item_source == nil then
@@ -105,7 +97,7 @@ function sources.get_signature_help_trigger_characters()
   local retrigger_characters = {}
 
   -- todo: should this be all source groups?
-  for _, source in ipairs(sources.sources_groups[1]) do
+  for _, source in ipairs(sources.providers) do
     local res = source:get_signature_help_trigger_characters()
     for _, char in ipairs(res.trigger_characters) do
       if not blocked_trigger_characters[char] then table.insert(trigger_characters, char) end
@@ -121,7 +113,7 @@ end
 --- @param callback fun(signature_helps: lsp.SignatureHelp)
 function sources.get_signature_help(context, callback)
   local tasks = {}
-  for _, source in ipairs(sources.sources_groups[1]) do
+  for _, source in ipairs(sources.providers) do
     table.insert(tasks, source:get_signature_help(context))
   end
   sources.current_signature_help = async.task.await_all(tasks):map(function(tasks_results)

lua/blink/cmp/sources/lib/source.lua renamed to lua/blink/cmp/sources/lib/provider.lua

@@ -4,8 +4,10 @@ local source = {}
 
 --- @param config blink.cmp.SourceProviderConfig
 function source.new(config)
+  assert(type(config.name) == 'string', 'Each source in config.sources.providers must have a "name" of type string')
+
   local self = setmetatable({}, { __index = source })
-  self.name = config[1]
+  self.name = config.name
   --- @type blink.cmp.Source
   self.module = require(config[1]).new(config.opts or {})
   self.config = config
@@ -45,13 +47,17 @@ function source:get_completions(context)
       for _, item in ipairs(response.items) do
         item.score_offset = (item.score_offset or 0) + (self.config.score_offset or 0)
         item.cursor_column = context.cursor[2]
-        item.source = self.config[1]
+        item.source = self.name
       end
 
       self.last_response = require('blink.cmp.utils').shallow_copy(response)
       self.last_response.is_cached = true
       return response
     end)
+    :catch(function(err)
+      vim.print('failed to get completions with error: ' .. err)
+      return { is_incomplete_forward = false, is_incomplete_backward = false, items = {} }
+    end)
 end
 
 --- @param response blink.cmp.CompletionResponse