Refactor to support positive and negative head branch filters

This replaces the proposed `head_branch_filter` option with two
options: `head_branches` selects PRs that match the specified glob,
and `ignore_head_branches` selects PRs that do not match the
specified glob.

This provides more control over filtering PRs based on the head
branch, and brings head branch filtering in line with what already
exists for path filtering.

README.md

@@ -34,7 +34,8 @@ Make sure to check out [#migrating](#migrating) to learn more.
 | `git_crypt_key`             | No       | `AEdJVENSWVBUS0VZAAAAA...`       | Base64 encoded git-crypt key. Setting this will unlock / decrypt the repository with git-crypt. To get the key simply execute `git-crypt export-key -- - | base64` in an encrypted repository.                                                                                             |
 | `base_branch`               | No       | `master`                         | Name of a branch. The pipeline will only trigger on pull requests against the specified branch.                                                                                                                                                                                            |
 | `labels`                    | No       | `["bug", "enhancement"]`         | The labels on the PR. The pipeline will only trigger on pull requests having at least one of the specified labels.                                                                                                                                                                         |
-| `head_branch_filter`        | No       | `release/*`                      | If specified, the pipeline will only trigger on pull requests for which the head branch name matches the specified glob pattern.                                                                                                                                                            |
+| `head_branches`        | No       | `release/*`                      | If specified, the pipeline will only trigger on pull requests for which the head branch name matches the specified glob pattern.                                                                                                                                                            |
+| `ignore_head_branches`        | No       | `release/*`                      | Inverse of the above                                                                                                                                                            |
 
 Notes:
  - If `v3_endpoint` is set, `v4_endpoint` must also be set (and the other way around).

check.go

@@ -38,9 +38,9 @@ Loop:
 			continue
 		}
 
-		// Filter pull request if the HeadRefName does not match the HeadBranchFilter specified in source
-		if request.Source.HeadBranchFilter != "" {
-			matched, err := filepath.Match(request.Source.HeadBranchFilter, p.PullRequestObject.HeadRefName)
+		// Skip pull request if the HeadRefName does not match the head_branches glob specified in source
+		if request.Source.HeadBranches != "" {
+			matched, err := filepath.Match(request.Source.HeadBranches, p.PullRequestObject.HeadRefName)
 			if err != nil {
 				return nil, fmt.Errorf("failed to apply head branch filter: %s", err)
 			}
@@ -49,6 +49,17 @@ Loop:
 			}
 		}
 
+		// Skip pull request if the HeadRefName matches the ignore_head_branches glob specified in source
+		if request.Source.IgnoreHeadBranches != "" {
+			matched, err := filepath.Match(request.Source.IgnoreHeadBranches, p.PullRequestObject.HeadRefName)
+			if err != nil {
+				return nil, fmt.Errorf("failed to apply ignore head branch filter: %s", err)
+			}
+			if matched {
+				continue
+			}
+		}
+
 		// Filter out pull request if it does not contain at least one of the desired labels
 		if len(request.Source.Labels) > 0 {
 			labelFound := false

check_test.go

@@ -189,15 +189,30 @@ func TestCheck(t *testing.T) {
 		{
 			description: "check correctly ignores PRs that do not match the head branch filter",
 			source: resource.Source{
-				Repository:       "itsdalmo/test-repository",
-				AccessToken:      "oauthtoken",
-				HeadBranchFilter: "pr2*",
+				Repository:   "itsdalmo/test-repository",
+				AccessToken:  "oauthtoken",
+				HeadBranches: "pr8*",
 			},
 			version:      resource.Version{},
 			pullRequests: testPullRequests,
 			files:        [][]string{},
 			expected: resource.CheckResponse{
-				resource.NewVersion(testPullRequests[1]),
+				resource.NewVersion(testPullRequests[7]),
+			},
+		},
+
+		{
+			description: "check correctly ignores PRs that do match the ignore head branch filter",
+			source: resource.Source{
+				Repository:         "itsdalmo/test-repository",
+				AccessToken:        "oauthtoken",
+				IgnoreHeadBranches: "pr2*",
+			},
+			version:      resource.Version{},
+			pullRequests: testPullRequests,
+			files:        [][]string{},
+			expected: resource.CheckResponse{
+				resource.NewVersion(testPullRequests[2]),
 			},
 		},
 	}

e2e/e2e_test.go

@@ -177,12 +177,12 @@ func TestCheckE2E(t *testing.T) {
 		{
 			description: "check returns latest PR that matches the head branch filter",
 			source: resource.Source{
-				Repository:       "itsdalmo/test-repository",
-				AccessToken:      os.Getenv("GITHUB_ACCESS_TOKEN"),
-				V3Endpoint:       "https://api.github.com/",
-				V4Endpoint:       "https://api.github.com/graphql",
-				HeadBranchFilter: "my*",
-				DisableCISkip:    true,
+				Repository:    "itsdalmo/test-repository",
+				AccessToken:   os.Getenv("GITHUB_ACCESS_TOKEN"),
+				V3Endpoint:    "https://api.github.com/",
+				V4Endpoint:    "https://api.github.com/graphql",
+				HeadBranches:  "my*",
+				DisableCISkip: true,
 			},
 			version: resource.Version{},
 			expected: resource.CheckResponse{
@@ -193,16 +193,48 @@ func TestCheckE2E(t *testing.T) {
 		{
 			description: "check works when head branch filter doesn't match any PRs",
 			source: resource.Source{
-				Repository:       "itsdalmo/test-repository",
-				AccessToken:      os.Getenv("GITHUB_ACCESS_TOKEN"),
-				V3Endpoint:       "https://api.github.com/",
-				V4Endpoint:       "https://api.github.com/graphql",
-				HeadBranchFilter: "feature/*",
-				DisableCISkip:    true,
+				Repository:    "itsdalmo/test-repository",
+				AccessToken:   os.Getenv("GITHUB_ACCESS_TOKEN"),
+				V3Endpoint:    "https://api.github.com/",
+				V4Endpoint:    "https://api.github.com/graphql",
+				HeadBranches:  "feature/*",
+				DisableCISkip: true,
 			},
 			version:  resource.Version{},
 			expected: resource.CheckResponse(nil),
 		},
+
+		{
+			description: "check returns latest PR that matches the ignore head branch filter",
+			source: resource.Source{
+				Repository:         "itsdalmo/test-repository",
+				AccessToken:        os.Getenv("GITHUB_ACCESS_TOKEN"),
+				V3Endpoint:         "https://api.github.com/",
+				V4Endpoint:         "https://api.github.com/graphql",
+				IgnoreHeadBranches: "test*",
+				DisableCISkip:      true,
+			},
+			version: resource.Version{},
+			expected: resource.CheckResponse{
+				resource.Version{PR: targetPullRequestID, Commit: targetCommitID, CommittedDate: targetDateTime},
+			},
+		},
+
+		{
+			description: "check works when ignore head branch filter doesn't match any PRs",
+			source: resource.Source{
+				Repository:         "itsdalmo/test-repository",
+				AccessToken:        os.Getenv("GITHUB_ACCESS_TOKEN"),
+				V3Endpoint:         "https://api.github.com/",
+				V4Endpoint:         "https://api.github.com/graphql",
+				IgnoreHeadBranches: "feature/*",
+				DisableCISkip:      true,
+			},
+			version: resource.Version{},
+			expected: resource.CheckResponse{
+				resource.Version{PR: developPullRequestID, Commit: developCommitID, CommittedDate: developDateTime},
+			},
+		},
 	}
 
 	for _, tc := range tests {

models.go

@@ -21,7 +21,8 @@ type Source struct {
 	DisableForks            bool     `json:"disable_forks"`
 	GitCryptKey             string   `json:"git_crypt_key"`
 	BaseBranch              string   `json:"base_branch"`
-	HeadBranchFilter        string   `json:"head_branch_filter"`
+	HeadBranches            string   `json:"head_branches"`
+	IgnoreHeadBranches      string   `json:"ignore_head_branches"`
 	RequiredReviewApprovals int      `json:"required_review_approvals"`
 	Labels                  []string `json:"labels"`
 }