add(bot): cut_body_after option for merge message

`cut_body_before` was added via #589

Add the second option, also handle the case where the match isn't found.

rel: #550

bot/kodiak/config.py

@@ -44,6 +44,7 @@ class MergeMessage(BaseModel):
     include_coauthors: bool = False
     include_pull_request_url: bool = False
     cut_body_before: str = ""
+    cut_body_after: str = ""
 
 
 # this pattern indicates that the user has the field unset.

bot/kodiak/evaluation.py

@@ -64,16 +64,23 @@
 
 
 def get_body_content(
+    *,
     body_type: BodyText,
     strip_html_comments: bool,
     cut_body_before: str,
+    cut_body_after: str,
     pull_request: PullRequest,
 ) -> str:
     if body_type == BodyText.markdown:
         body = pull_request.body
         if cut_body_before != "":
             start_index = body.find(cut_body_before)
-            body = body[start_index:]
+            if start_index != -1:
+                body = body[start_index:]
+        if cut_body_after != "":
+            end_index = body.find(cut_body_after)
+            if end_index != -1:
+                body = body[: end_index + len(cut_body_after)]
         if strip_html_comments:
             return strip_html_comments_from_markdown(body)
         return body
@@ -168,10 +175,11 @@ def get_merge_body(
     merge_body = MergeBody(merge_method=merge_method)
     if config.merge.message.body == MergeBodyStyle.pull_request_body:
         body = get_body_content(
-            config.merge.message.body_type,
-            config.merge.message.strip_html_comments,
-            config.merge.message.cut_body_before,
-            pull_request,
+            body_type=config.merge.message.body_type,
+            strip_html_comments=config.merge.message.strip_html_comments,
+            cut_body_before=config.merge.message.cut_body_before,
+            cut_body_after=config.merge.message.cut_body_after,
+            pull_request=pull_request,
         )
         merge_body.commit_message = body
     if config.merge.message.body == MergeBodyStyle.empty:

bot/kodiak/test/fixtures/config/config-schema.json

@@ -33,7 +33,8 @@
           "include_pull_request_author": false,
           "include_coauthors": false,
           "include_pull_request_url": false,
-          "cut_body_before": ""
+          "cut_body_before": "",
+          "cut_body_after": ""
         },
         "dont_wait_on_status_checks": [],
         "update_branch_immediately": false,
@@ -143,6 +144,11 @@
           "title": "Cut Body Before",
           "default": "",
           "type": "string"
+        },
+        "cut_body_after": {
+          "title": "Cut Body After",
+          "default": "",
+          "type": "string"
         }
       }
     },
@@ -236,7 +242,8 @@
             "include_pull_request_author": false,
             "include_coauthors": false,
             "include_pull_request_url": false,
-            "cut_body_before": ""
+            "cut_body_before": "",
+            "cut_body_after": ""
           },
           "allOf": [
             {

bot/kodiak/test_evaluation.py

@@ -3048,6 +3048,132 @@ def test_get_merge_body_strip_html_comments() -> None:
     assert actual == expected
 
 
+def test_get_merge_body_cut_body_after() -> None:
+    """
+    Basic check of cut_body_after removing content.
+    """
+    pull_request = create_pull_request()
+    pull_request.body = "hello <!-- testing -->world"
+    actual = get_merge_body(
+        config=V1(
+            version=1,
+            merge=Merge(
+                message=MergeMessage(
+                    body=MergeBodyStyle.pull_request_body,
+                    cut_body_after="<!-- testing -->",
+                )
+            ),
+        ),
+        pull_request=pull_request,
+        merge_method=MergeMethod.squash,
+        commits=[],
+    )
+    expected = MergeBody(merge_method="squash", commit_message="hello <!-- testing -->")
+    assert actual == expected
+
+
+def test_get_merge_body_cut_body_after_strip_html() -> None:
+    """
+    We should be able to use strip_html_comments with cut_body_after.
+    """
+    pull_request = create_pull_request()
+    pull_request.body = "hello <!-- testing -->world"
+    actual = get_merge_body(
+        config=V1(
+            version=1,
+            merge=Merge(
+                message=MergeMessage(
+                    body=MergeBodyStyle.pull_request_body,
+                    cut_body_after="<!-- testing -->",
+                    strip_html_comments=True,
+                )
+            ),
+        ),
+        pull_request=pull_request,
+        merge_method=MergeMethod.squash,
+        commits=[],
+    )
+    expected = MergeBody(merge_method="squash", commit_message="hello ")
+    assert actual == expected
+
+
+def test_get_merge_body_cut_body_after_multiple_markers() -> None:
+    """
+    We should choose the first substring matching cut_body_after.
+    """
+    pull_request = create_pull_request()
+    pull_request.body = "hello <!-- testing -->world<!-- testing --> 123"
+    actual = get_merge_body(
+        config=V1(
+            version=1,
+            merge=Merge(
+                message=MergeMessage(
+                    body=MergeBodyStyle.pull_request_body,
+                    cut_body_after="<!-- testing -->",
+                    strip_html_comments=True,
+                )
+            ),
+        ),
+        pull_request=pull_request,
+        merge_method=MergeMethod.squash,
+        commits=[],
+    )
+    expected = MergeBody(merge_method="squash", commit_message="hello ")
+    assert actual == expected
+
+
+def test_get_merge_body_cut_body_after_no_match_found() -> None:
+    """
+    Ensure we don't edit the message if there isn't any match found with
+    cut_body_after.
+    """
+    pull_request = create_pull_request()
+    pr_body = "hello <!-- foo -->world<!-- bar --> 123"
+    pull_request.body = pr_body
+    actual = get_merge_body(
+        config=V1(
+            version=1,
+            merge=Merge(
+                message=MergeMessage(
+                    body=MergeBodyStyle.pull_request_body,
+                    cut_body_after="<!-- buzz -->",
+                )
+            ),
+        ),
+        pull_request=pull_request,
+        merge_method=MergeMethod.squash,
+        commits=[],
+    )
+    expected = MergeBody(merge_method="squash", commit_message=pr_body)
+    assert actual == expected
+
+
+def test_get_merge_body_cut_body_before_no_match_found() -> None:
+    """
+    Ensure we don't edit the message if there isn't any match found with
+    cut_body_before.
+    """
+    pull_request = create_pull_request()
+    pr_body = "hello <!-- foo -->world<!-- bar --> 123"
+    pull_request.body = pr_body
+    actual = get_merge_body(
+        config=V1(
+            version=1,
+            merge=Merge(
+                message=MergeMessage(
+                    body=MergeBodyStyle.pull_request_body,
+                    cut_body_before="<!-- buzz -->",
+                )
+            ),
+        ),
+        pull_request=pull_request,
+        merge_method=MergeMethod.squash,
+        commits=[],
+    )
+    expected = MergeBody(merge_method="squash", commit_message=pr_body)
+    assert actual == expected
+
+
 def test_get_merge_body_cut_body_before() -> None:
     pull_request = create_pull_request()
     pull_request.body = "hello <!-- testing -->world"