From 08842cd6bb0fd6ce3f53b2547993413a5eb6bf10 Mon Sep 17 00:00:00 2001
From: Matt Clay <mclay@redhat.com>
Date: Thu, 3 Dec 2020 09:19:03 -0800
Subject: [PATCH] Fix Azure Pipelines change detection. (#72824)

---
 .../fragments/ansible-test-azp-change-detection.yml       | 2 ++
 test/lib/ansible_test/_internal/ci/azp.py                 | 8 ++++----
 2 files changed, 6 insertions(+), 4 deletions(-)
 create mode 100644 changelogs/fragments/ansible-test-azp-change-detection.yml

diff --git a/changelogs/fragments/ansible-test-azp-change-detection.yml b/changelogs/fragments/ansible-test-azp-change-detection.yml
new file mode 100644
index 00000000000..ae69618fa43
--- /dev/null
+++ b/changelogs/fragments/ansible-test-azp-change-detection.yml
@@ -0,0 +1,2 @@
+bugfixes:
+    - ansible-test - Correctly detect changes in a GitHub pull request when running on Azure Pipelines.
diff --git a/test/lib/ansible_test/_internal/ci/azp.py b/test/lib/ansible_test/_internal/ci/azp.py
index 962e838e7c5..f2a9d206cc7 100644
--- a/test/lib/ansible_test/_internal/ci/azp.py
+++ b/test/lib/ansible_test/_internal/ci/azp.py
@@ -208,10 +208,10 @@ class AzurePipelinesChanges:
         if self.base_commit:
             self.base_commit = self.git.run_git(['rev-parse', self.base_commit]).strip()
 
-            # <rev1>...<rev2>
-            # Include commits that are reachable from <rev2> but exclude those that are reachable from <rev1>.
-            # see: https://git-scm.com/docs/gitrevisions
-            dot_range = '%s..%s' % (self.base_commit, self.commit)
+            # <commit>...<commit>
+            # This form is to view the changes on the branch containing and up to the second <commit>, starting at a common ancestor of both <commit>.
+            # see: https://git-scm.com/docs/git-diff
+            dot_range = '%s...%s' % (self.base_commit, self.commit)
 
             self.paths = sorted(self.git.get_diff_names([dot_range]))
             self.diff = self.git.get_diff([dot_range])