use three dot notation to calculate diff

Author: stickperson

coverage_comment/coverage.py

@@ -293,7 +293,7 @@ def get_added_lines(
     # don't merge chunks. This means the headers that describe line number
     # are always enough to derive what line numbers were added.
     git.fetch("origin", base_ref, "--depth=1000")
-    diff = git.diff("--unified=0", "FETCH_HEAD", "--", ".")
+    diff = git.diff("--unified=0", "FETCH_HEAD...HEAD")
     return parse_diff_output(diff)
 
 

tests/integration/conftest.py

@@ -0,0 +1,101 @@
+from __future__ import annotations
+
+import os
+import pathlib
+import subprocess
+import uuid
+
+import pytest
+
+
+@pytest.fixture
+def in_integration_env(integration_env, integration_dir):
+    curdir = os.getcwd()
+    os.chdir(integration_dir)
+    yield integration_dir
+    os.chdir(curdir)
+
+
+@pytest.fixture
+def integration_dir(tmp_path: pathlib.Path):
+    test_dir = tmp_path / "integration_test"
+    test_dir.mkdir()
+    return test_dir
+
+
+@pytest.fixture
+def file_path(integration_dir):
+    return integration_dir / "foo.py"
+
+
+@pytest.fixture
+def write_file(file_path):
+    def _(*variables):
+        content = "import os"
+        for i, var in enumerate(variables):
+            content += f"""\nif os.environ.get("{var}"):\n    {i}\n"""
+        file_path.write_text(content, encoding="utf8")
+
+    return _
+
+
+@pytest.fixture
+def run_coverage(file_path, integration_dir):
+    def _(*variables):
+        subprocess.check_call(
+            ["coverage", "run", "--parallel", file_path.name],
+            cwd=integration_dir,
+            env=os.environ | dict.fromkeys(variables, "1"),
+        )
+
+    return _
+
+
+@pytest.fixture
+def commit(integration_dir):
+    def _():
+        subprocess.check_call(
+            ["git", "add", "."],
+            cwd=integration_dir,
+        )
+        subprocess.check_call(
+            ["git", "commit", "-m", str(uuid.uuid4())],
+            cwd=integration_dir,
+            env={
+                "GIT_AUTHOR_NAME": "foo",
+                "GIT_AUTHOR_EMAIL": "foo",
+                "GIT_COMMITTER_NAME": "foo",
+                "GIT_COMMITTER_EMAIL": "foo",
+                "GIT_CONFIG_GLOBAL": "/dev/null",
+                "GIT_CONFIG_SYSTEM": "/dev/null",
+            },
+        )
+
+    return _
+
+
+@pytest.fixture
+def integration_env(integration_dir, write_file, run_coverage, commit, request):
+    subprocess.check_call(["git", "init", "-b", "main"], cwd=integration_dir)
+    # diff coverage reads the "origin/{...}" branch so we simulate an origin remote
+    subprocess.check_call(["git", "remote", "add", "origin", "."], cwd=integration_dir)
+    write_file("A", "B")
+    commit()
+
+    add_branch_mark = request.node.get_closest_marker("add_branches")
+    for additional_branch in add_branch_mark.args if add_branch_mark else []:
+        subprocess.check_call(
+            ["git", "switch", "-c", additional_branch],
+            cwd=integration_dir,
+        )
+
+    subprocess.check_call(
+        ["git", "switch", "-c", "branch"],
+        cwd=integration_dir,
+    )
+
+    write_file("A", "B", "C", "D")
+    commit()
+
+    run_coverage("A", "C")
+    subprocess.check_call(["git", "fetch", "origin"], cwd=integration_dir)

tests/integration/test_coverage.py

@@ -0,0 +1,30 @@
+from __future__ import annotations
+
+import subprocess
+from coverage_comment import coverage, subprocess as subprocess_module
+
+
+def test_get_added_lines(
+    commit, file_path, integration_dir, in_integration_env, write_file
+):
+    """
+    Lines added in the base_ref should not appear as added in HEAD
+    """
+    git = subprocess_module.Git()
+    relative_file_path = file_path.relative_to(integration_dir)
+
+    def _check_added_lines():
+        added_lines = coverage.get_added_lines(git, "main")
+
+        assert added_lines == {
+            relative_file_path: list(range(7, 13))  # Line numbers start at 1
+        }
+
+    _check_added_lines()
+    subprocess.check_call(["git", "switch", "main"], cwd=integration_dir)
+    write_file("E", "F")
+    commit()
+    subprocess.check_call(["git", "push", "origin", "main"], cwd=integration_dir)
+    subprocess.check_call(["git", "switch", "branch"], cwd=integration_dir)
+
+    _check_added_lines()

tests/integration/test_main.py

@@ -172,7 +172,7 @@ def checker(payload):
     )(status_code=403)
 
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     result = main.action(
         config=pull_request_config(
@@ -253,7 +253,7 @@ def checker(payload):
     )(status_code=403)
 
     git.register("git fetch origin foo --depth=1000")(stdout=DIFF_STDOUT)
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     result = main.action(
         config=pull_request_config(
@@ -300,7 +300,7 @@ def test_action__pull_request__post_comment(
     session.register("GET", "/repos/py-cov-action/foobar/issues/2/comments")(json=[])
 
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     comment = None
 
@@ -347,7 +347,7 @@ def test_action__push__non_default_branch(
         json={"default_branch": "main", "visibility": "public"}
     )
     git.register("git fetch origin main --depth=1000")(stdout=DIFF_STDOUT)
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     payload = json.dumps({"coverage": 30.00})
     # There is an existing badge in this test, allowing to test the coverage evolution
@@ -436,7 +436,7 @@ def test_action__push__non_default_branch__no_pr(
         json={"default_branch": "main", "visibility": "public"}
     )
     git.register("git fetch origin main --depth=1000")(stdout=DIFF_STDOUT)
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     payload = json.dumps({"coverage": 30.00})
     # There is an existing badge in this test, allowing to test the coverage evolution
@@ -500,7 +500,7 @@ def test_action__pull_request__force_store_comment(
     )(text=payload, headers={"content-type": "application/vnd.github.raw+json"})
 
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     result = main.action(
         config=pull_request_config(FORCE_WORKFLOW_RUN=True, GITHUB_OUTPUT=output_file),
@@ -531,7 +531,7 @@ def test_action__pull_request__post_comment__no_marker(
     )(status_code=404)
 
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     result = main.action(
         config=pull_request_config(COMMENT_TEMPLATE="""foo"""),
@@ -556,7 +556,7 @@ def test_action__pull_request__annotations(
     )(status_code=404)
 
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     # Who am I
     session.register("GET", "/user")(json={"login": "foo"})
@@ -598,7 +598,7 @@ def test_action__pull_request__post_comment__template_error(
     )(status_code=404)
 
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=DIFF_STDOUT)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=DIFF_STDOUT)
 
     result = main.action(
         config=pull_request_config(COMMENT_TEMPLATE="""{%"""),

tests/unit/test_coverage.py

@@ -309,7 +309,7 @@ def test_get_added_lines(git):
         """+++ b/README.md\n@@ -1,2 +1,3 @@\n-# coverage-comment\n+coverage-comment\n"""
     )
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=diff)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=diff)
     assert coverage.get_added_lines(git=git, base_ref="main") == {
         pathlib.Path("README.md"): [1, 2, 3]
     }
@@ -364,7 +364,7 @@ def test_parse_diff_output(git):
 rename to coverage_comment/annotations2.py
 """
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=diff)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=diff)
     assert coverage.parse_diff_output(diff=diff) == {
         pathlib.Path("README.md"): [1, 3, 4, 5, 6],
         pathlib.Path("foo.txt"): [1],
@@ -379,6 +379,6 @@ def test_parse_diff_output__error(git):
 index 1f1d9a4..e69de29 100644
 """
     git.register("git fetch origin main --depth=1000")()
-    git.register("git diff --unified=0 FETCH_HEAD -- .")(stdout=diff)
+    git.register("git diff --unified=0 FETCH_HEAD...HEAD")(stdout=diff)
     with pytest.raises(ValueError):
         coverage.parse_diff_output(diff=diff)