fix(bitbucket): avoid extra plans using a local LRU

.gitignore

@@ -24,3 +24,6 @@ dist/
 tmp-CHANGELOG.md
 
 .envrc
+
+# IDE files
+*.code-workspace

go.mod

@@ -20,6 +20,7 @@ require (
 	github.com/hashicorp/go-getter/v2 v2.2.1
 	github.com/hashicorp/go-multierror v1.1.1
 	github.com/hashicorp/go-version v1.6.0
+	github.com/hashicorp/golang-lru/v2 v2.0.2
 	github.com/hashicorp/terraform-config-inspect v0.0.0-20230413234026-f1617e8a5fcc
 	github.com/kr/pretty v0.3.1
 	github.com/mcdafydd/go-azuredevops v0.12.1

go.sum

@@ -249,6 +249,9 @@ github.com/hashicorp/go-version v1.6.0 h1:feTTfFNnjP967rlCxM/I9g701jU+RN74YKx2mO
 github.com/hashicorp/go-version v1.6.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
+github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+lJfyTc=
+github.com/hashicorp/golang-lru/v2 v2.0.2 h1:Dwmkdr5Nc/oBiXgJS3CDHNhJtIHkuZ3DZF5twqnfBdU=
+github.com/hashicorp/golang-lru/v2 v2.0.2/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
 github.com/hashicorp/hcl/v2 v2.16.2 h1:mpkHZh/Tv+xet3sy3F9Ld4FyI2tUpWe9x3XtPx9f1a0=

server/controllers/events/events_controller.go

@@ -366,7 +366,8 @@ func (e *VCSEventsController) handleBitbucketCloudPullRequestEvent(w http.Respon
 		e.respond(w, logging.Error, http.StatusBadRequest, "Error parsing pull data: %s %s=%s", err, bitbucketCloudRequestIDHeader, reqID)
 		return
 	}
-	pullEventType := e.Parser.GetBitbucketCloudPullEventType(eventType)
+	e.Logger.Debug("SHA is %q", pull.HeadCommit)
+	pullEventType := e.Parser.GetBitbucketCloudPullEventType(eventType, pull.HeadCommit, pull.URL)
 	e.Logger.Info("identified event as type %q", pullEventType.String())
 	resp := e.handlePullRequestEvent(e.Logger, baseRepo, headRepo, pull, user, pullEventType)
 

server/events/event_parser.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/go-playground/validator/v10"
 	"github.com/google/go-github/v52/github"
+	lru "github.com/hashicorp/golang-lru/v2"
 	"github.com/mcdafydd/go-azuredevops/azuredevops"
 	"github.com/pkg/errors"
 	"github.com/runatlantis/atlantis/server/events/command"
@@ -34,6 +35,8 @@ import (
 const gitlabPullOpened = "opened"
 const usagesCols = 90
 
+var lastBitbucketSha, _ = lru.New[string, string](300)
+
 // PullCommand is a command to run on a pull request.
 type PullCommand interface {
 	// CommandName is the name of the command we're running.
@@ -267,7 +270,7 @@ type EventParsing interface {
 
 	// GetBitbucketCloudPullEventType returns the type of the pull request
 	// event given the Bitbucket Cloud header.
-	GetBitbucketCloudPullEventType(eventTypeHeader string) models.PullRequestEventType
+	GetBitbucketCloudPullEventType(eventTypeHeader string, sha string, pr string) models.PullRequestEventType
 
 	// ParseBitbucketServerPullEvent parses a pull request event from Bitbucket
 	// Server.
@@ -343,11 +346,18 @@ func (e *EventParser) ParseAPIPlanRequest(vcsHostType models.VCSHostType, repoFu
 
 // GetBitbucketCloudPullEventType returns the type of the pull request
 // event given the Bitbucket Cloud header.
-func (e *EventParser) GetBitbucketCloudPullEventType(eventTypeHeader string) models.PullRequestEventType {
+func (e *EventParser) GetBitbucketCloudPullEventType(eventTypeHeader string, sha string, pr string) models.PullRequestEventType {
 	switch eventTypeHeader {
 	case bitbucketcloud.PullCreatedHeader:
+		lastBitbucketSha.Add(pr, sha)
 		return models.OpenedPullEvent
 	case bitbucketcloud.PullUpdatedHeader:
+		lastSha, _ := lastBitbucketSha.Get(pr)
+		if sha == lastSha {
+			// No change, ignore
+			return models.OtherPullEvent
+		}
+		lastBitbucketSha.Add(pr, sha)
 		return models.UpdatedPullEvent
 	case bitbucketcloud.PullFulfilledHeader, bitbucketcloud.PullRejectedHeader:
 		return models.ClosedPullEvent

server/events/event_parser_test.go

@@ -984,6 +984,42 @@ func TestParseBitbucketCloudPullEvent_States(t *testing.T) {
 	}
 }
 
+func TestBitBucketNonCodeChangesAreIgnored(t *testing.T) {
+	// lets say a user opens a PR
+	act := parser.GetBitbucketCloudPullEventType("pullrequest:created", "fakeSha", "https://github.com/fakeorg/fakerepo/pull/1")
+	Equals(t, models.OpenedPullEvent, act)
+	// Another update with same SHA should be ignored
+	act = parser.GetBitbucketCloudPullEventType("pullrequest:updated", "fakeSha", "https://github.com/fakeorg/fakerepo/pull/1")
+	Equals(t, models.OtherPullEvent, act)
+	// Only if SHA changes do we act
+	act = parser.GetBitbucketCloudPullEventType("pullrequest:updated", "fakeSha2", "https://github.com/fakeorg/fakerepo/pull/1")
+	Equals(t, models.UpdatedPullEvent, act)
+
+	// If sha changes in seperate PR,
+	act = parser.GetBitbucketCloudPullEventType("pullrequest:updated", "otherPRSha", "https://github.com/fakeorg/fakerepo/pull/2")
+	Equals(t, models.UpdatedPullEvent, act)
+	// We will still ignore same shas in first PR
+	act = parser.GetBitbucketCloudPullEventType("pullrequest:updated", "fakeSha2", "https://github.com/fakeorg/fakerepo/pull/1")
+	Equals(t, models.OtherPullEvent, act)
+}
+
+func TestBitbucketShaCacheExpires(t *testing.T) {
+	// lets say a user opens a PR
+	act := parser.GetBitbucketCloudPullEventType("pullrequest:created", "fakeSha", "https://github.com/fakeorg/fakerepo/pull/1")
+	Equals(t, models.OpenedPullEvent, act)
+	// Another update with same SHA should be ignored
+	act = parser.GetBitbucketCloudPullEventType("pullrequest:updated", "fakeSha", "https://github.com/fakeorg/fakerepo/pull/1")
+	Equals(t, models.OtherPullEvent, act)
+	// But after 300 times, the cache should expire
+	// this is so we don't have ever increasing memory usage
+	for i := 0; i < 302; i++ {
+		parser.GetBitbucketCloudPullEventType("pullrequest:updated", "fakeSha", fmt.Sprintf("https://github.com/fakeorg/fakerepo/pull/%d", i))
+	}
+	// and now SHA will seen as a change again
+	act = parser.GetBitbucketCloudPullEventType("pullrequest:updated", "fakeSha", "https://github.com/fakeorg/fakerepo/pull/1")
+	Equals(t, models.UpdatedPullEvent, act)
+}
+
 func TestGetBitbucketCloudEventType(t *testing.T) {
 	cases := []struct {
 		header string
@@ -1012,7 +1048,9 @@ func TestGetBitbucketCloudEventType(t *testing.T) {
 	}
 	for _, c := range cases {
 		t.Run(c.header, func(t *testing.T) {
-			act := parser.GetBitbucketCloudPullEventType(c.header)
+			// we pass in the header as the SHA so the SHA changes each time
+			// the code will ignore duplicate SHAS to avoid extra TF plans
+			act := parser.GetBitbucketCloudPullEventType(c.header, c.header, "https://github.com/fakeorg/fakerepo/pull/1")
 			Equals(t, c.exp, act)
 		})
 	}