add conditional support (if) to steps

Author: jasonwbarnett

go.sum

@@ -1,7 +1,3 @@
-github.com/bmatcuk/doublestar/v4 v4.8.1 h1:54Bopc5c2cAvhLRAzqOGCYHYyhcDHsFF4wWIR5wKP38=
-github.com/bmatcuk/doublestar/v4 v4.8.1/go.mod h1:xBQ8jztBU6kakFMg+8WGxn0c6z1fTSPVIjEY1Wr7jzc=
-github.com/bmatcuk/doublestar/v4 v4.9.0 h1:DBvuZxjdKkRP/dr4GVV4w2fnmrk5Hxc90T51LZjv0JA=
-github.com/bmatcuk/doublestar/v4 v4.9.0/go.mod h1:xBQ8jztBU6kakFMg+8WGxn0c6z1fTSPVIjEY1Wr7jzc=
 github.com/bmatcuk/doublestar/v4 v4.9.1 h1:X8jg9rRZmJd4yRy7ZeNDRnM+T3ZfHv15JiBJ/avrEXE=
 github.com/bmatcuk/doublestar/v4 v4.9.1/go.mod h1:xBQ8jztBU6kakFMg+8WGxn0c6z1fTSPVIjEY1Wr7jzc=
 github.com/buildkite/bintest/v3 v3.3.0 h1:RTWcSaJRlOT6t/K311ejPf+0J3LE/QEODzVG3vlLnWo=

pipeline_test.go

@@ -547,3 +547,36 @@ func TestGeneratePipelineWithNoStepsAndNoHooks(t *testing.T) {
 
 	assert.Equal(t, want, string(got))
 }
+
+func TestGeneratePipelineWithCondition(t *testing.T) {
+	steps := []Step{
+		{
+			Command:   "echo deploy to production",
+			Label:     "Deploy",
+			Condition: "build.branch == 'main' && build.pull_request.id == null",
+		},
+		{
+			Trigger:   "test-pipeline",
+			Condition: "build.message =~ /\\[deploy\\]/",
+		},
+	}
+
+	want := `steps:
+    - label: Deploy
+      if: build.branch == 'main' && build.pull_request.id == null
+      command: echo deploy to production
+    - trigger: test-pipeline
+      if: build.message =~ /\[deploy\]/
+`
+
+	plugin := Plugin{Wait: false}
+
+	pipeline, _, err := generatePipeline(steps, plugin)
+	require.NoError(t, err)
+	defer os.Remove(pipeline.Name())
+
+	got, err := os.ReadFile(pipeline.Name())
+	require.NoError(t, err)
+
+	assert.Equal(t, want, string(got))
+}

plugin.go

@@ -80,6 +80,7 @@ type Step struct {
 	Trigger   string                   `yaml:"trigger,omitempty"`
 	Label     string                   `yaml:"label,omitempty"`
 	Branches  string                   `yaml:"branches,omitempty"`
+	Condition string                   `json:"if,omitempty" yaml:"if,omitempty"`
 	Build     Build                    `yaml:"build,omitempty"`
 	Command   interface{}              `yaml:"command,omitempty"`
 	Commands  interface{}              `yaml:"commands,omitempty"`

plugin_test.go

@@ -824,3 +824,42 @@ func TestPluginLevelMetadataNotAppliedToCommandSteps(t *testing.T) {
 	assert.Equal(t, "echo Make Changes to Bin", commandStep.Command)
 	assert.Nil(t, commandStep.Build.Metadata, "Command step should not have metadata applied")
 }
+
+func TestPluginShouldPreserveStepCondition(t *testing.T) {
+	param := `[{
+		"github.com/buildkite-plugins/monorepo-diff-buildkite-plugin#commit": {
+			"watch": [
+				{
+					"path": "service/**/*",
+					"config": {
+						"command": "echo deploy",
+						"if": "build.branch == 'main' && build.pull_request.id == null"
+					}
+				}
+			]
+		}
+	}]`
+
+	got, err := initializePlugin(param)
+	assert.NoError(t, err)
+
+	expected := Plugin{
+		Diff:          "git diff --name-only HEAD~1",
+		Wait:          false,
+		LogLevel:      "info",
+		Interpolation: true,
+		Watch: []WatchConfig{
+			{
+				Paths: []string{"service/**/*"},
+				Step: Step{
+					Command:   "echo deploy",
+					Condition: "build.branch == 'main' && build.pull_request.id == null",
+				},
+			},
+		},
+	}
+
+	if diff := cmp.Diff(expected, got); diff != "" {
+		t.Fatalf("plugin diff (-want +got):\n%s", diff)
+	}
+}