`:skip_undefined_reference_warnings_on` not working for given module?

[kianmeng]

Deps:

$ MIX_ENV=docs mix deps
* connection 1.0.4 (Hex package) (mix)
  locked at 1.0.4 (connection) 4a0850c9
  ok
* db_connection 2.2.2 (Hex package) (mix)
  locked at 2.2.2 (db_connection) 642af240
  ok
* decimal 1.9.0 (Hex package) (mix)
  locked at 1.9.0 (decimal) b1f23435
  ok
+* earmark_parser 1.4.10 (Hex package) (mix)
+ locked at 1.4.10 (earmark_parser) 8e2d5370
+  ok
* ecto 3.5.2 (Hex package) (mix)
  locked at 3.5.2 (ecto) fd92cfb1
  ok
+* ex_doc 0.23.0 (Hex package) (mix)
+locked at 0.23.0 (ex_doc) f5e2c470
+ok
* jason 1.2.2 (Hex package) (mix)
  locked at 1.2.2 (jason) 18a228f5
  ok
* makeup 1.0.5 (Hex package) (mix)
  locked at 1.0.5 (makeup) cfa158c0
  ok
* makeup_elixir 0.15.0 (Hex package) (mix)
  locked at 0.15.0 (makeup_elixir) 75ffa34a
  ok
* myxql 0.3.3 (Hex package) (mix)
  locked at 0.3.3 (myxql) a9466d83
  ok
* nimble_parsec 1.1.0 (Hex package) (mix)
  locked at 1.1.0 (nimble_parsec) 08eb32d6
  ok
* postgrex 0.15.5 (Hex package) (mix)
  locked at 0.15.5 (postgrex) ed90c81e
  ok
* tds 2.1.1 (Hex package) (mix)
  locked at 2.1.1 (tds) 6b28e1f0
  ok
* telemetry 0.4.2 (Hex package) (rebar3)
  locked at 0.4.2 (telemetry) 2d1419bd
  ok

Actual:

Steps to reproduce:

1. git clone https://github.com/elixir-ecto/ecto_sql.git
2. mix deps.get
3. Update mix.exs and add this line 177:

  176       source_url: "https://github.com/elixir-ecto/ecto_sql", 
+ 177       skip_undefined_reference_warnings_on: ["DBConnection.ConnectionPool"], 
  178       groups_for_modules: [

4. MIX_ENV=docs mix docs

Generating docs...
warning: documentation references module "DBConnection.ConnectionPool" but it is hidden
  lib/ecto/adapters/myxql.ex:2: Ecto.Adapters.MyXQL

warning: documentation references module "DBConnection.ConnectionPool" but it is hidden
  lib/ecto/adapters/postgres.ex:2: Ecto.Adapters.Postgres

warning: documentation references module "DBConnection.ConnectionPool" but it is hidden
  lib/ecto/adapters/tds.ex:2: Ecto.Adapters.Tds

View "html" docs at "doc/index.html"
warning: documentation references module "DBConnection.ConnectionPool" but it is hidden
  lib/ecto/adapters/myxql.ex:2: Ecto.Adapters.MyXQL

warning: documentation references module "DBConnection.ConnectionPool" but it is hidden
  lib/ecto/adapters/postgres.ex:2: Ecto.Adapters.Postgres

warning: documentation references module "DBConnection.ConnectionPool" but it is hidden
  lib/ecto/adapters/tds.ex:2: Ecto.Adapters.Tds

View "epub" docs at "doc/Ecto SQL.epub"

Expected:

MIX_ENV=docs mix docs
Generating docs...
View "html" docs at "doc/index.html"
View "epub" docs at "doc/Ecto SQL.epub"

Did I use the :skip_undefined_reference_warnings_on option incorrectly or is it a bug?

[eksperimental]

Hi @kianmeng,
could you please update ex_doc to the lastest version ("~> 0.23") and see if the issue still happens

[eksperimental]

There are two issues.

1. there is already a key named :skip_undefined_reference_warnings_on in that keywordlist, it is just on line 179.
2. :skip_undefined_reference_warnings_on does not work for modules you link to as in this case, but for modules you link from. If you add Ecto.Adapters.Postgres you will see the warning is gone.

[eksperimental]

This was previously proposed in #1192 and had a PR #1249 but it didn't make its way in.

[kianmeng]

@eksperimental, Awesome! Thanks for clarifying my misunderstanding of the :skip_undefined_reference_warnings_on option and shared the historical context of :skip_reference_warnings_for option. 👍 👍