Do not run clone step if no pipeline step will run (#877)

Skip the clone step and ignore hook/pipeline if no pipeline step except clone would run. The status reported back to the forge is `success`.

Closes https://github.com/woodpecker-ci/woodpecker/issues/778

pipeline/frontend/yaml/compiler/compiler.go

@@ -183,6 +183,7 @@ func (c *Compiler) Compile(conf *yaml.Config) *backend.Config {
 		config.Stages = append(config.Stages, stage)
 	}
 
+	var stages []*backend.Stage
 	// add pipeline steps. 1 pipeline step per stage, at the moment
 	var stage *backend.Stage
 	var group string
@@ -202,7 +203,7 @@ func (c *Compiler) Compile(conf *yaml.Config) *backend.Config {
 			stage = new(backend.Stage)
 			stage.Name = fmt.Sprintf("%s_stage_%v", c.prefix, i)
 			stage.Alias = container.Name
-			config.Stages = append(config.Stages, stage)
+			stages = append(stages, stage)
 		}
 
 		name := fmt.Sprintf("%s_step_%d", c.prefix, i)
@@ -210,6 +211,13 @@ func (c *Compiler) Compile(conf *yaml.Config) *backend.Config {
 		stage.Steps = append(stage.Steps, step)
 	}
 
+	if len(stages) == 0 {
+		// nothing will run, remove services and clone step
+		config.Stages = []*backend.Stage{}
+	} else {
+		config.Stages = append(config.Stages, stages...)
+	}
+
 	c.setupCacheRebuild(conf, config)
 
 	return config

server/api/hook.go

@@ -200,10 +200,20 @@ func PostHook(c *gin.Context) {
 		return
 	}
 
-	if zeroSteps(build, remoteYamlConfigs) {
+	// TODO: move global pipeline filters into own check functions ...
+	if z, steps := zeroSteps(build, remoteYamlConfigs); z {
 		msg := "ignoring hook: step conditions yield zero runnable steps"
 		log.Debug().Str("repo", repo.FullName).Msg(msg)
 		c.String(http.StatusOK, msg)
+		build.Status = model.StatusSuccess
+		for _, step := range steps {
+			step.Proc.State = model.StatusSuccess
+			build.Procs = append(build.Procs, step.Proc)
+		}
+		// TODO: this wont create any builds the status can link to ...
+		if err := updateBuildStatus(c, build, repo, repoUser); err != nil {
+			log.Error().Err(err).Msg("updateBuildStatus")
+		}
 		return
 	}
 
@@ -292,7 +302,7 @@ func branchFiltered(build *model.Build, remoteYamlConfigs []*remote.FileMeta) (b
 	return true, nil
 }
 
-func zeroSteps(build *model.Build, remoteYamlConfigs []*remote.FileMeta) bool {
+func zeroSteps(build *model.Build, remoteYamlConfigs []*remote.FileMeta) (bool, []*shared.BuildItem) {
 	b := shared.ProcBuilder{
 		Repo:  &model.Repo{},
 		Curr:  build,
@@ -304,15 +314,16 @@ func zeroSteps(build *model.Build, remoteYamlConfigs []*remote.FileMeta) bool {
 		Yamls: remoteYamlConfigs,
 	}
 
+	buildItemsNoEmpty, err := b.Build()
+	if err != nil {
+		return false, []*shared.BuildItem{}
+	}
+	b.IncludeEmpty = true
 	buildItems, err := b.Build()
 	if err != nil {
-		return false
+		return false, []*shared.BuildItem{}
 	}
-	if len(buildItems) == 0 {
-		return true
-	}
-
-	return false
+	return len(buildItemsNoEmpty) == 0, buildItems
 }
 
 func findOrPersistPipelineConfig(store store.Store, build *model.Build, remoteYamlConfig *remote.FileMeta) (*model.Config, error) {

server/shared/procBuilder.go

@@ -37,15 +37,16 @@ import (
 
 // ProcBuilder Takes the hook data and the yaml and returns in internal data model
 type ProcBuilder struct {
-	Repo  *model.Repo
-	Curr  *model.Build
-	Last  *model.Build
-	Netrc *model.Netrc
-	Secs  []*model.Secret
-	Regs  []*model.Registry
-	Link  string
-	Yamls []*remote.FileMeta
-	Envs  map[string]string
+	Repo         *model.Repo
+	Curr         *model.Build
+	Last         *model.Build
+	Netrc        *model.Netrc
+	Secs         []*model.Secret
+	Regs         []*model.Registry
+	Link         string
+	Yamls        []*remote.FileMeta
+	Envs         map[string]string
+	IncludeEmpty bool
 }
 
 type BuildItem struct {
@@ -114,7 +115,7 @@ func (b *ProcBuilder) Build() ([]*BuildItem, error) {
 
 			ir := b.toInternalRepresentation(parsed, environ, metadata, proc.ID)
 
-			if len(ir.Stages) == 0 {
+			if len(ir.Stages) == 0 && !b.IncludeEmpty {
 				continue
 			}
 
@@ -138,7 +139,6 @@ func (b *ProcBuilder) Build() ([]*BuildItem, error) {
 	items = filterItemsWithMissingDependencies(items)
 
 	// check if at least one proc can start, if list is not empty
-	procListContainsItemsToRun(items)
 	if len(items) > 0 && !procListContainsItemsToRun(items) {
 		return nil, fmt.Errorf("build has no startpoint")
 	}