gh-554: Handle Draft PRs (#555)

Don't add "awaiting" labels to Draft PR, only add them when PR is published (not draft anymore)
Remove "awaiting" labels again when PR becomes unpublished.

Closes #554

Author: itamaro

README.md

@@ -11,14 +11,14 @@ If no GitHub issue number is found the status fails and the
 "Details" link points to the relevant
 [section of the devguide](https://devguide.python.org/getting-started/pull-request-lifecycle.html#submitting).
 - ### Links to GitHub issues
-If an issue number is found then the "Details" link points to the relevant issue 
+If an issue number is found then the "Details" link points to the relevant issue
 itself, making it easier to navigate from PR to issue.
 - ### Identifies missing news entry
-If no `Misc/NEWS.d` entry is found or the news entry is formatted incorrectly 
-and the issue doesn't have the `skip news` label, the status fails and a relevant 
+If no `Misc/NEWS.d` entry is found or the news entry is formatted incorrectly
+and the issue doesn't have the `skip news` label, the status fails and a relevant
 description label is added to it.
 - ### Closes invalid PRs
-Closes PRs that try to merge a maintenance branch into the main branch, adds 
+Closes PRs that try to merge a maintenance branch into the main branch, adds
 `invalid` label, and posts a relevant message.
 - ### Labels PRs for docs
 Labels PRs for documentation as `type-documentation`
@@ -43,7 +43,9 @@ blocking the PR from moving forward:
 
 ```mermaid
 flowchart TD
-    A([New PR]):::creator
+    A([Published PR]):::creator
+    A_draft([New Draft PR]):::creator
+    A_draft -- publish draft by contributor --> A:::creator
     A -- by contributor --> B[Awaiting review]:::anyone
     A -- by core dev --> C[Awaiting core review]:::coredev
     B & C -- new review by\nanother contributor --> C

bedevere/stage.py

@@ -109,6 +109,8 @@ async def opened_pr(event, gh, *arg, **kwargs):
     "awaiting review".
     """
     pull_request = event.data["pull_request"]
+    if pull_request.get("draft"):
+        return
     issue = await util.issue_for_PR(gh, pull_request)
     username = util.user_login(pull_request)
     if await util.is_core_dev(gh, username):
@@ -117,6 +119,18 @@ async def opened_pr(event, gh, *arg, **kwargs):
         await stage(gh, issue, Blocker.review)
 
 
+@router.register("pull_request", action="edited")
+async def edited_pr(event, gh, *arg, **kwargs):
+    pull_request = event.data["pull_request"]
+    issue = await util.issue_for_PR(gh, pull_request)
+    username = util.user_login(pull_request)
+    if pull_request.get("draft"):
+        await _remove_stage_labels(gh, issue)
+    else:
+        blocked_on = Blocker.core_review if await util.is_core_dev(gh, username) else Blocker.review
+        await stage(gh, issue, blocked_on)
+
+
 @router.register("push")
 async def new_commit_pushed(event, gh, *arg, **kwargs):
     """If there is a new commit pushed to the PR branch that is in `awaiting merge` state,

tests/test_stage.py

@@ -72,6 +72,74 @@ async def test_stage():
     assert post_[1] == [awaiting.Blocker.merge.value]
 
 
+async def test_opened_draft_pr():
+    # New Draft PR from a core dev.
+    username = "brettcannon"
+    issue_url = "https://api.github.com/issue/42"
+    data = {
+        "action": "opened",
+        "pull_request": {
+            "user": {
+                "login": username,
+            },
+            "issue_url": issue_url,
+            "draft": True,
+        },
+    }
+    event = sansio.Event(data, event="pull_request", delivery_id="12345")
+    teams = [{"name": "python core", "id": 6}]
+    items = {
+        f"https://api.github.com/teams/6/memberships/{username}": "OK",
+        issue_url: {"labels": [], "labels_url": "https://api.github.com/labels"},
+    }
+    gh = FakeGH(
+        getiter={"https://api.github.com/orgs/python/teams": teams}, getitem=items
+    )
+    await awaiting.router.dispatch(event, gh)
+    assert len(gh.post_) == 0
+
+    # Draft PR is published
+    data["action"] = "edited"
+    data["pull_request"]["draft"] = False
+    event = sansio.Event(data, event="pull_request", delivery_id="12345")
+    gh = FakeGH(
+        getiter={"https://api.github.com/orgs/python/teams": teams}, getitem=items
+    )
+    await awaiting.router.dispatch(event, gh)
+    assert len(gh.post_) == 1
+    post_ = gh.post_[0]
+    assert post_[0] == "https://api.github.com/labels"
+    assert post_[1] == [awaiting.Blocker.core_review.value]
+
+    # Published PR is unpublished (set back to Draft)
+    data["action"] = "edited"
+    data["pull_request"]["draft"] = True
+    encoded_label = "awaiting%20core%20review"
+    items[issue_url] = {
+        "labels": [
+            {
+                "url": f"https://api.github.com/repos/python/cpython/labels/{encoded_label}",
+                "name": "awaiting core review",
+            },
+            {
+                "url": "https://api.github.com/repos/python/cpython/labels/CLA%20signed",
+                "name": "CLA signed",
+            },
+        ],
+        "labels_url": "https://api.github.com/repos/python/cpython/issues/12345/labels{/name}",
+    }
+    event = sansio.Event(data, event="pull_request", delivery_id="12345")
+    gh = FakeGH(
+        getiter={"https://api.github.com/orgs/python/teams": teams}, getitem=items
+    )
+    await awaiting.router.dispatch(event, gh)
+    assert len(gh.post_) == 0
+    assert (
+        gh.delete_url ==
+        f"https://api.github.com/repos/python/cpython/issues/12345/labels/{encoded_label}"
+    )
+
+
 async def test_opened_pr():
     # New PR from a core dev.
     username = "brettcannon"
@@ -110,6 +178,7 @@ async def test_opened_pr():
                 "login": username,
             },
             "issue_url": issue_url,
+            "draft": False,
         },
     }
     event = sansio.Event(data, event="pull_request", delivery_id="12345")