[github] Don't consider PR body in CI skip logic

GitHub pull request edits were not triggering CI when the PR
body/description contained the `[ ci skip ]`/`[ skip ci ]` pattern. This
was an issue, for example, in Dependabot-generated PRs that include
commit messages from upstream dependencies that do include the pattern.
Furthermore, no other CI service or vendor considers the PR body for the
"ci skip" mechanism.  This corrects the behavior so that only commit
messages or PR titles are considered when a PR is edited.

Author: usmonster

service/hook/github/github.go

@@ -179,11 +179,19 @@ func transformPullRequestEvent(pullRequest PullRequestEventModel) hookCommon.Tra
 		}
 	}
 	if pullRequest.Action == "edited" {
-		// skip it if only title / description changed, and the previous pattern did not include a [skip ci] pattern
+		// skip it if only title / description changed, and the current title did not remove a [skip ci] pattern
 		if pullRequest.Changes.Base == nil {
-			if !hookCommon.IsSkipBuildByCommitMessage(pullRequest.Changes.Title.From) && !hookCommon.IsSkipBuildByCommitMessage(pullRequest.Changes.Body.From) {
+			// only description changed
+			if pullRequest.Changes.Title.From == "" {
 				return hookCommon.TransformResultModel{
-					Error:      errors.New("Pull Request edit doesn't require a build: only title and/or description was changed, and previous one was not skipped"),
+					Error:      errors.New("Pull Request edit doesn't require a build: only body/description was changed"),
+					ShouldSkip: true,
+				}
+			}
+			// title changed without removing any [skip ci] pattern
+			if !hookCommon.IsSkipBuildByCommitMessage(pullRequest.Changes.Title.From) {
+				return hookCommon.TransformResultModel{
+					Error:      errors.New("Pull Request edit doesn't require a build: only title was changed, and previous one was not skipped"),
 					ShouldSkip: true,
 				}
 			}

service/hook/github/github_test.go

@@ -654,7 +654,7 @@ func Test_transformPullRequestEvent(t *testing.T) {
 			},
 		}
 		hookTransformResult := transformPullRequestEvent(pullRequest)
-		require.EqualError(t, hookTransformResult.Error, "Pull Request edit doesn't require a build: only title and/or description was changed, and previous one was not skipped")
+		require.EqualError(t, hookTransformResult.Error, "Pull Request edit doesn't require a build: only title was changed, and previous one was not skipped")
 		require.True(t, hookTransformResult.ShouldSkip)
 		require.Equal(t, []bitriseapi.TriggerAPIParamsModel(nil), hookTransformResult.TriggerAPIParams)
 		require.Equal(t, false, hookTransformResult.DontWaitForTriggerResponse)
@@ -717,7 +717,7 @@ func Test_transformPullRequestEvent(t *testing.T) {
 		require.Equal(t, false, hookTransformResult.DontWaitForTriggerResponse)
 	}
 
-	t.Log("Pull Request - edited - only body/description change - no skip ci in previous - no build")
+	t.Log("Pull Request - edited - only body/description change - no build")
 	{
 		pullRequest := PullRequestEventModel{
 			Action:        "edited",
@@ -753,13 +753,13 @@ func Test_transformPullRequestEvent(t *testing.T) {
 			},
 		}
 		hookTransformResult := transformPullRequestEvent(pullRequest)
-		require.EqualError(t, hookTransformResult.Error, "Pull Request edit doesn't require a build: only title and/or description was changed, and previous one was not skipped")
+		require.EqualError(t, hookTransformResult.Error, "Pull Request edit doesn't require a build: only body/description was changed")
 		require.True(t, hookTransformResult.ShouldSkip)
 		require.Equal(t, []bitriseapi.TriggerAPIParamsModel(nil), hookTransformResult.TriggerAPIParams)
 		require.Equal(t, false, hookTransformResult.DontWaitForTriggerResponse)
 	}
 
-	t.Log("Pull Request - edited - only body/description change - BUT the previous title included a skip CI pattern - should build")
+	t.Log("Pull Request - edited - only body/description change - the previous body included a skip CI pattern - still shouldn't build")
 	{
 		pullRequest := PullRequestEventModel{
 			Action:        "edited",
@@ -795,24 +795,9 @@ func Test_transformPullRequestEvent(t *testing.T) {
 			},
 		}
 		hookTransformResult := transformPullRequestEvent(pullRequest)
-		require.NoError(t, hookTransformResult.Error)
-		require.False(t, hookTransformResult.ShouldSkip)
-		require.Equal(t, []bitriseapi.TriggerAPIParamsModel{
-			{
-				BuildParams: bitriseapi.BuildParamsModel{
-					CommitHash:               "83b86e5f286f546dc5a4a58db66ceef44460c85e",
-					CommitMessage:            "PR test\n\nPR text body",
-					Branch:                   "feature/github-pr",
-					BranchDest:               "develop",
-					PullRequestID:            pointers.NewIntPtr(12),
-					PullRequestRepositoryURL: "https://github.com/bitrise-io/bitrise-webhooks.git",
-					BaseRepositoryURL:        "https://github.com/bitrise-io/bitrise-webhooks.git",
-					HeadRepositoryURL:        "https://github.com/bitrise-io/bitrise-webhooks.git",
-					PullRequestMergeBranch:   "pull/12/merge",
-					PullRequestHeadBranch:    "pull/12/head",
-				},
-			},
-		}, hookTransformResult.TriggerAPIParams)
+		require.EqualError(t, hookTransformResult.Error, "Pull Request edit doesn't require a build: only body/description was changed")
+		require.True(t, hookTransformResult.ShouldSkip)
+		require.Equal(t, []bitriseapi.TriggerAPIParamsModel(nil), hookTransformResult.TriggerAPIParams)
 		require.Equal(t, false, hookTransformResult.DontWaitForTriggerResponse)
 	}
 }