Skip to content

Use process_info(PID, parent) #164

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
whatyouhide merged 1 commit into from
Mar 30, 2025
+28 −7
Merged

Use process_info(PID, parent) #164

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
29 changes: 28 additions & 1 deletion lib/mox.ex
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -183,6 +183,13 @@ defmodule Mox do
`$callers` is used to determine the process that actually defined the
expectations.

> #### Parent PIDs {: .tip}
> [Since OTP 25](https://erlang.org/documentation/doc-15.0-rc2/erts-14.3/doc/html/notes.html#erts-13-0),
> `Process.info/2` supports a `:parent` key for retrieving the parent of the given PID.
> Mox started using this in v1.3.0 to determine process tree structures in case `$callers`
> is not available in the process dictionary. This means that even more allowance cases
> are taken care of automatically.

#### Explicit allowances as lazy/deferred functions

Under some circumstances, the process might not have been already started
Expand Down Expand Up @@ -941,7 +948,27 @@ defmodule Mox do

# Find the pid of the actual caller
defp caller_pids do
Process.get(:"$callers", [])
case Process.get(:"$callers") do
nil -> [self() | recursive_parents(self())]
pids when is_list(pids) -> pids
end
end

# A PID with no parent has :undefined as its parent.
defp recursive_parents(:undefined) do
[]
end

defp recursive_parents(pid) when is_pid(pid) do
Process.info(pid, :parent)
rescue
# erlang:process_info(Pid, parent) is not available, as it was released in
# ERTS 13.0 (https://erlang.org/documentation/doc-15.0-rc2/erts-14.3/doc/html/notes.html#erts-13-0)
ArgumentError ->
[]
else
{:parent, parent_pid} ->
[parent_pid | recursive_parents(parent_pid)]
end

## Ownership
Expand Down
6 changes: 0 additions & 6 deletions test/mox_test.exs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -846,8 +846,6 @@ defmodule MoxTest do

{:ok, child_pid} =
start_link_no_callers(fn ->
assert_raise Mox.UnexpectedCallError, fn -> CalcMock.add(1, 1) end

receive do
:call_mock ->
add_result = CalcMock.add(1, 1)
Expand Down Expand Up @@ -876,8 +874,6 @@ defmodule MoxTest do
|> stub(:mult, fn _, _ -> :stubbed end)

async_no_callers(fn ->
assert_raise Mox.UnexpectedCallError, fn -> CalcMock.add(1, 1) end

CalcMock
|> allow(parent_pid, self())

Expand All @@ -892,8 +888,6 @@ defmodule MoxTest do

{:ok, child_pid} =
start_link_no_callers(fn ->
assert_raise(Mox.UnexpectedCallError, fn -> CalcMock.add(1, 1) end)

receive do
:call_mock ->
add_result = CalcMock.add(1, 1)
Expand Down
Loading