fix(actions): let a rerun of selected jobs read the previous attempt's artifacts (#38857)

Fixes #38773

## Background

Artifacts became attempt-scoped in #37119, and the runner-facing
artifact APIs filter strictly by the attempt of the running job. "Re-run
failed jobs" creates a new attempt whose passed-through jobs never
upload their artifacts again, so a re-run job that downloads one of them
fails with "artifact not found".

## Fix

The read paths (v3 and v4 list and download) now resolve artifacts
across the running job's attempt plus the attempts it inherits from, and
an inherited artifact is shadowed by a same-named one from a newer
attempt.

## Note

GitHub's documentation does not document these behaviors. The
conclusions below are based on manual testing, so consistency with
GitHub cannot be guaranteed.

- In a "partial re-run", a job can download artifacts uploaded by an
earlier attempt, every attempt keeps its own copy of a name, and a
lookup by name resolves to the newest one.
- A full "Re-run all jobs" never downloads artifacts from earlier
attempts.

---------

Co-authored-by: bircni <bircni@icloud.com>

models/actions/artifact.go

@@ -9,10 +9,10 @@ package actions
 import (
 	"context"
 	"errors"
+	"slices"
 	"time"
 
 	"gitea.dev/models/db"
-	"gitea.dev/modules/optional"
 	"gitea.dev/modules/timeutil"
 	"gitea.dev/modules/util"
 
@@ -147,7 +147,7 @@ type FindArtifactsOptions struct {
 	db.ListOptions
 	RepoID               int64
 	RunID                int64
-	RunAttemptID         optional.Option[int64] // use optional to allow filtering by zero (legacy artifacts have run_attempt_id=0)
+	RunAttemptIDs        []int64 // empty means every attempt; pass 0 to target legacy artifacts, which have run_attempt_id=0
 	ArtifactName         string
 	Status               int
 	FinalizedArtifactsV4 bool
@@ -167,8 +167,8 @@ func (opts FindArtifactsOptions) ToConds() builder.Cond {
 	if opts.RunID > 0 {
 		cond = cond.And(builder.Eq{"run_id": opts.RunID})
 	}
-	if opts.RunAttemptID.Has() {
-		cond = cond.And(builder.Eq{"run_attempt_id": opts.RunAttemptID.Value()})
+	if len(opts.RunAttemptIDs) > 0 {
+		cond = cond.And(builder.In("run_attempt_id", opts.RunAttemptIDs))
 	}
 	if opts.ArtifactName != "" {
 		cond = cond.And(builder.Eq{"artifact_name": opts.ArtifactName})
@@ -185,6 +185,27 @@ func (opts FindArtifactsOptions) ToConds() builder.Cond {
 	return cond
 }
 
+// FindReadableArtifacts returns the artifacts of opts.RunAttemptIDs, only keeps the ones from a newer attempt.
+func FindReadableArtifacts(ctx context.Context, opts FindArtifactsOptions) ([]*ActionArtifact, error) {
+	arts, err := db.Find[ActionArtifact](ctx, opts)
+	if err != nil || len(opts.RunAttemptIDs) <= 1 {
+		return arts, err
+	}
+	return keepLatestAttemptArtifacts(arts), nil
+}
+
+// keepLatestAttemptArtifacts keeps, per name, only the artifacts of the newest attempt that has it.
+// A v3 artifact is one row per uploaded file, so the whole group of the winning attempt is kept.
+func keepLatestAttemptArtifacts(arts []*ActionArtifact) []*ActionArtifact {
+	latest := make(map[string]int64)
+	for _, art := range arts {
+		latest[art.ArtifactName] = max(latest[art.ArtifactName], art.RunAttemptID)
+	}
+	return slices.DeleteFunc(arts, func(art *ActionArtifact) bool {
+		return art.RunAttemptID != latest[art.ArtifactName]
+	})
+}
+
 // ActionArtifactMeta is the meta-data of an artifact
 type ActionArtifactMeta struct {
 	ArtifactName string

models/actions/artifact_test.go

@@ -0,0 +1,27 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestKeepLatestAttemptArtifacts(t *testing.T) {
+	arts := []*ActionArtifact{
+		{ID: 1, RunAttemptID: 1, ArtifactName: "inherited"},
+		{ID: 2, RunAttemptID: 1, ArtifactName: "shadowed", ArtifactPath: "a.txt"},
+		{ID: 3, RunAttemptID: 1, ArtifactName: "shadowed", ArtifactPath: "b.txt"},
+		{ID: 4, RunAttemptID: 2, ArtifactName: "shadowed", ArtifactPath: "c.txt"},
+		{ID: 5, RunAttemptID: 2, ArtifactName: "own"},
+	}
+
+	// the whole "shadowed" group of attempt 1 is dropped, its multi-file rows must not mix with attempt 2
+	var ids []int64
+	for _, art := range keepLatestAttemptArtifacts(arts) {
+		ids = append(ids, art.ID)
+	}
+	assert.Equal(t, []int64{1, 4, 5}, ids)
+}

models/actions/run_attempt.go

@@ -11,6 +11,7 @@ import (
 
 	"gitea.dev/models/db"
 	user_model "gitea.dev/models/user"
+	"gitea.dev/modules/container"
 	"gitea.dev/modules/log"
 	"gitea.dev/modules/timeutil"
 	"gitea.dev/modules/util"
@@ -96,6 +97,56 @@ func GetRunAttemptByRunIDAndAttemptNum(ctx context.Context, runID, attemptNum in
 	return &attempt, nil
 }
 
+// GetArtifactAttemptIDs returns the IDs of the attempts whose artifacts the job may read, newest first,
+// always including the job's own attempt.
+// An attempt that re-ran only some of the run's jobs keeps the artifacts of the attempt it re-ran from,
+// because the jobs it passed through never upload them again; a rerun of the whole run starts over.
+func GetArtifactAttemptIDs(ctx context.Context, job *ActionRunJob) ([]int64, error) {
+	if job.Attempt <= 1 || job.RunAttemptID == 0 {
+		return []int64{job.RunAttemptID}, nil
+	}
+
+	attempts, err := ListRunAttemptsByRunID(ctx, job.RunID)
+	if err != nil {
+		return nil, err
+	}
+	// a newer attempt is never readable, and attempt 1 has nothing older to continue into
+	candidateIDs := container.FilterSlice(attempts, func(a *ActionRunAttempt) (int64, bool) {
+		return a.ID, a.Attempt > 1 && a.Attempt <= job.Attempt
+	})
+	passThroughAttemptIDs, err := findPassThroughAttemptIDs(ctx, candidateIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	ids := make([]int64, 0, len(attempts))
+	for _, attempt := range attempts {
+		if attempt.Attempt > job.Attempt {
+			continue
+		}
+		ids = append(ids, attempt.ID)
+		if !slices.Contains(passThroughAttemptIDs, attempt.ID) {
+			// stops at the first attempt that passed no job through
+			break
+		}
+	}
+	return ids, nil
+}
+
+// findPassThroughAttemptIDs narrows the given attempts to those that were a rerun of selected jobs:
+// only such a rerun clones jobs carrying a source task.
+// TODO: best-effort. Needs a better way to distinguish between "partial re-run" and "full re-run".
+func findPassThroughAttemptIDs(ctx context.Context, attemptIDs []int64) ([]int64, error) {
+	passThroughAttemptIDs := make([]int64, 0, len(attemptIDs))
+	return passThroughAttemptIDs, db.GetEngine(ctx).
+		Table("action_run_job").
+		Cols("run_attempt_id").
+		In("run_attempt_id", attemptIDs).
+		Where("source_task_id <> 0").
+		Distinct("run_attempt_id").
+		Find(&passThroughAttemptIDs)
+}
+
 // FindConcurrentRunAttempts returns attempts in the given concurrency group and status set.
 // Results are unordered; callers must not depend on any particular row order.
 func FindConcurrentRunAttempts(ctx context.Context, repoID int64, concurrencyGroup string, statuses []Status) ([]*ActionRunAttempt, error) {

routers/api/actions/artifacts.go

@@ -66,6 +66,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"slices"
 	"strconv"
 	"strings"
 
@@ -74,7 +75,6 @@ import (
 	"gitea.dev/modules/httplib"
 	"gitea.dev/modules/json"
 	"gitea.dev/modules/log"
-	"gitea.dev/modules/optional"
 	"gitea.dev/modules/reqctx"
 	"gitea.dev/modules/setting"
 	"gitea.dev/modules/storage"
@@ -337,15 +337,19 @@ type (
 )
 
 func (ar artifactRoutes) listArtifacts(ctx *ArtifactContext) {
-	_, runID, ok := validateRunID(ctx)
+	task, runID, ok := validateRunID(ctx)
+	if !ok {
+		return
+	}
+	attemptIDs, ok := readableArtifactAttemptIDs(ctx, task)
 	if !ok {
 		return
 	}
 
-	artifacts, err := db.Find[actions.ActionArtifact](ctx, actions.FindArtifactsOptions{
-		RunID:        runID,
-		RunAttemptID: optional.Some(ctx.ActionTask.Job.RunAttemptID),
-		Status:       int(actions.ArtifactStatusUploadConfirmed),
+	artifacts, err := actions.FindReadableArtifacts(ctx, actions.FindArtifactsOptions{
+		RunID:         runID,
+		RunAttemptIDs: attemptIDs,
+		Status:        int(actions.ArtifactStatusUploadConfirmed),
 	})
 	if err != nil {
 		log.Error("Error getting artifacts: %v", err)
@@ -398,7 +402,7 @@ type (
 
 // getDownloadArtifactURL generates download url for each artifact
 func (ar artifactRoutes) getDownloadArtifactURL(ctx *ArtifactContext) {
-	_, runID, ok := validateRunID(ctx)
+	task, runID, ok := validateRunID(ctx)
 	if !ok {
 		return
 	}
@@ -408,11 +412,16 @@ func (ar artifactRoutes) getDownloadArtifactURL(ctx *ArtifactContext) {
 		return
 	}
 
-	artifacts, err := db.Find[actions.ActionArtifact](ctx, actions.FindArtifactsOptions{
-		RunID:        runID,
-		RunAttemptID: optional.Some(ctx.ActionTask.Job.RunAttemptID),
-		ArtifactName: itemPath,
-		Status:       int(actions.ArtifactStatusUploadConfirmed),
+	attemptIDs, ok := readableArtifactAttemptIDs(ctx, task)
+	if !ok {
+		return
+	}
+
+	artifacts, err := actions.FindReadableArtifacts(ctx, actions.FindArtifactsOptions{
+		RunID:         runID,
+		RunAttemptIDs: attemptIDs,
+		ArtifactName:  itemPath,
+		Status:        int(actions.ArtifactStatusUploadConfirmed),
 	})
 	if err != nil {
 		log.Error("Error getting artifacts: %v", err)
@@ -462,7 +471,7 @@ func (ar artifactRoutes) getDownloadArtifactURL(ctx *ArtifactContext) {
 
 // downloadArtifact downloads artifact content
 func (ar artifactRoutes) downloadArtifact(ctx *ArtifactContext) {
-	_, runID, ok := validateRunID(ctx)
+	task, runID, ok := validateRunID(ctx)
 	if !ok {
 		return
 	}
@@ -484,10 +493,17 @@ func (ar artifactRoutes) downloadArtifact(ctx *ArtifactContext) {
 		ctx.HTTPError(http.StatusBadRequest)
 		return
 	}
-	if ctx.ActionTask.Job.RunAttemptID > 0 && artifact.RunAttemptID != ctx.ActionTask.Job.RunAttemptID {
-		log.Error("Error mismatch runAttemptID and artifactID, task: %v, artifact: %v", ctx.ActionTask.Job.RunAttemptID, artifactID)
-		ctx.HTTPError(http.StatusBadRequest)
-		return
+	// resolving the readable attempts costs a query, and an artifact of the task's own attempt never needs it
+	if artifact.RunAttemptID != task.Job.RunAttemptID {
+		attemptIDs, ok := readableArtifactAttemptIDs(ctx, task)
+		if !ok {
+			return
+		}
+		if !slices.Contains(attemptIDs, artifact.RunAttemptID) {
+			log.Error("Error artifact %d belongs to run attempt %d, which the task cannot read: %v", artifactID, artifact.RunAttemptID, attemptIDs)
+			ctx.HTTPError(http.StatusBadRequest)
+			return
+		}
 	}
 	if artifact.Status != actions.ArtifactStatusUploadConfirmed {
 		log.Error("Error artifact not found: %s", artifact.Status.ToString())

routers/api/actions/artifacts_chunks.go

@@ -20,7 +20,6 @@ import (
 	"gitea.dev/models/actions"
 	"gitea.dev/models/db"
 	"gitea.dev/modules/log"
-	"gitea.dev/modules/optional"
 	"gitea.dev/modules/setting"
 	"gitea.dev/modules/storage"
 )
@@ -261,9 +260,9 @@ func listOrderedChunksForArtifact(st storage.ObjectStorage, runID, artifactID in
 func mergeChunksForRun(ctx *ArtifactContext, st storage.ObjectStorage, runID, runAttemptID int64, artifactName string) error {
 	// read all db artifacts by name
 	artifacts, err := db.Find[actions.ActionArtifact](ctx, actions.FindArtifactsOptions{
-		RunID:        runID,
-		RunAttemptID: optional.Some(runAttemptID),
-		ArtifactName: artifactName,
+		RunID:         runID,
+		RunAttemptIDs: []int64{runAttemptID},
+		ArtifactName:  artifactName,
 	})
 	if err != nil {
 		return err

routers/api/actions/artifacts_utils.go

@@ -43,7 +43,7 @@ func validateRunID(ctx *ArtifactContext) (*actions.ActionTask, int64, bool) {
 	return task, runID, true
 }
 
-func validateRunIDV4(ctx *ArtifactContext, rawRunID string) (*actions.ActionTask, int64, bool) { //nolint:unparam // ActionTask is never used
+func validateRunIDV4(ctx *ArtifactContext, rawRunID string) (*actions.ActionTask, int64, bool) {
 	task := ctx.ActionTask
 	runID, err := strconv.ParseInt(rawRunID, 10, 64)
 	if err != nil || task.Job.RunID != runID {
@@ -54,6 +54,18 @@ func validateRunIDV4(ctx *ArtifactContext, rawRunID string) (*actions.ActionTask
 	return task, runID, true
 }
 
+// readableArtifactAttemptIDs resolves the attempts a task may read artifacts from:
+// its own attempt, plus the attempts it inherits from when only a subset of the run's jobs was re-run.
+func readableArtifactAttemptIDs(ctx *ArtifactContext, task *actions.ActionTask) ([]int64, bool) {
+	attemptIDs, err := actions.GetArtifactAttemptIDs(ctx, task.Job)
+	if err != nil {
+		log.Error("Error getting readable artifact attempts: %v", err)
+		ctx.HTTPError(http.StatusInternalServerError, "Error getting readable artifact attempts")
+		return nil, false
+	}
+	return attemptIDs, true
+}
+
 func validateArtifactHash(ctx *ArtifactContext, artifactName string) bool {
 	paramHash := ctx.PathParam("artifact_hash")
 	// use artifact name to create upload url

routers/api/actions/artifactsv4.go

@@ -107,7 +107,6 @@ import (
 	actions_module "gitea.dev/modules/actions"
 	"gitea.dev/modules/httplib"
 	"gitea.dev/modules/log"
-	"gitea.dev/modules/optional"
 	"gitea.dev/modules/setting"
 	"gitea.dev/modules/storage"
 	"gitea.dev/modules/util"
@@ -262,9 +261,28 @@ func (r *artifactV4Routes) verifySignature(ctx *ArtifactContext, endp string) (*
 	return task, artifactName, true
 }
 
-func (r *artifactV4Routes) getArtifactByName(ctx *ArtifactContext, runID, runAttemptID int64, name string) (*actions_model.ActionArtifact, error) {
+// getOwnAttemptArtifactByName resolves an artifact of the given attempt whatever its status,
+// since upload and finalize work on the pending row they just created.
+func (r *artifactV4Routes) getOwnAttemptArtifactByName(ctx *ArtifactContext, runID, runAttemptID int64, name string) (*actions_model.ActionArtifact, error) {
+	return r.findArtifactByName(ctx, runID, []int64{runAttemptID}, name, nil)
+}
+
+// getDownloadableArtifactByName resolves the newest artifact with the given name within the attempts whose content can still be served,
+// so a pending, deleted or expired row of a newer attempt does not shadow the confirmed copy inherited from an older one.
+func (r *artifactV4Routes) getDownloadableArtifactByName(ctx *ArtifactContext, runID int64, runAttemptIDs []int64, name string) (*actions_model.ActionArtifact, error) {
+	return r.findArtifactByName(ctx, runID, runAttemptIDs, name, builder.Eq{"status": actions_model.ArtifactStatusUploadConfirmed})
+}
+
+func (r *artifactV4Routes) findArtifactByName(ctx *ArtifactContext, runID int64, runAttemptIDs []int64, name string, extraCond builder.Cond) (*actions_model.ActionArtifact, error) {
+	cond := builder.NewCond().
+		And(builder.Eq{"run_id": runID, "artifact_name": name}, builder.Like{"content_encoding", "%/%"}).
+		And(builder.In("run_attempt_id", runAttemptIDs))
+	if extraCond != nil {
+		cond = cond.And(extraCond)
+	}
+
 	var art actions_model.ActionArtifact
-	has, err := db.GetEngine(ctx).Where(builder.Eq{"run_id": runID, "run_attempt_id": runAttemptID, "artifact_name": name}, builder.Like{"content_encoding", "%/%"}).Get(&art)
+	has, err := db.GetEngine(ctx).Where(cond).OrderBy("run_attempt_id DESC, id DESC").Get(&art)
 	if err != nil {
 		return nil, err
 	} else if !has {
@@ -384,7 +402,7 @@ func (r *artifactV4Routes) uploadArtifact(ctx *ArtifactContext) {
 	switch comp {
 	case "block", "appendBlock":
 		// get artifact by name
-		artifact, err := r.getArtifactByName(ctx, task.Job.RunID, task.Job.RunAttemptID, artifactName)
+		artifact, err := r.getOwnAttemptArtifactByName(ctx, task.Job.RunID, task.Job.RunAttemptID, artifactName)
 		if err != nil {
 			log.Error("Error artifact not found: %v", err)
 			ctx.HTTPError(http.StatusNotFound, "Error artifact not found")
@@ -471,7 +489,7 @@ func (r *artifactV4Routes) finalizeArtifact(ctx *ArtifactContext) {
 	}
 
 	// get artifact by name
-	artifact, err := r.getArtifactByName(ctx, runID, ctx.ActionTask.Job.RunAttemptID, req.Name)
+	artifact, err := r.getOwnAttemptArtifactByName(ctx, runID, ctx.ActionTask.Job.RunAttemptID, req.Name)
 	if err != nil {
 		log.Error("Error artifact not found: %v", err)
 		ctx.HTTPError(http.StatusNotFound, "Error artifact not found")
@@ -578,14 +596,18 @@ func (r *artifactV4Routes) listArtifacts(ctx *ArtifactContext) {
 	if ok := r.parseProtobufBody(ctx, &req); !ok {
 		return
 	}
-	_, runID, ok := validateRunIDV4(ctx, req.WorkflowRunBackendId)
+	task, runID, ok := validateRunIDV4(ctx, req.WorkflowRunBackendId)
+	if !ok {
+		return
+	}
+	attemptIDs, ok := readableArtifactAttemptIDs(ctx, task)
 	if !ok {
 		return
 	}
 
-	artifacts, err := db.Find[actions_model.ActionArtifact](ctx, actions_model.FindArtifactsOptions{
+	artifacts, err := actions_model.FindReadableArtifacts(ctx, actions_model.FindArtifactsOptions{
 		RunID:                runID,
-		RunAttemptID:         optional.Some(ctx.ActionTask.Job.RunAttemptID),
+		RunAttemptIDs:        attemptIDs,
 		Status:               int(actions_model.ArtifactStatusUploadConfirmed),
 		FinalizedArtifactsV4: true,
 	})
@@ -597,6 +619,8 @@ func (r *artifactV4Routes) listArtifacts(ctx *ArtifactContext) {
 
 	list := []*ListArtifactsResponse_MonolithArtifact{}
 
+	// both filters pick from what this attempt may read, so they run after the shadowed artifacts are gone:
+	// a shadowed artifact is not downloadable either, GetSignedArtifactURL resolves by name
 	table := map[string]*ListArtifactsResponse_MonolithArtifact{}
 	for _, artifact := range artifacts {
 		if _, ok := table[artifact.ArtifactName]; ok || req.IdFilter != nil && artifact.ID != req.IdFilter.Value || req.NameFilter != nil && artifact.ArtifactName != req.NameFilter.Value {
@@ -631,7 +655,11 @@ func (r *artifactV4Routes) getSignedArtifactURL(ctx *ArtifactContext) {
 	if ok := r.parseProtobufBody(ctx, &req); !ok {
 		return
 	}
-	_, runID, ok := validateRunIDV4(ctx, req.WorkflowRunBackendId)
+	task, runID, ok := validateRunIDV4(ctx, req.WorkflowRunBackendId)
+	if !ok {
+		return
+	}
+	attemptIDs, ok := readableArtifactAttemptIDs(ctx, task)
 	if !ok {
 		return
 	}
@@ -639,17 +667,12 @@ func (r *artifactV4Routes) getSignedArtifactURL(ctx *ArtifactContext) {
 	artifactName := req.Name
 
 	// get artifact by name
-	artifact, err := r.getArtifactByName(ctx, runID, ctx.ActionTask.Job.RunAttemptID, artifactName)
+	artifact, err := r.getDownloadableArtifactByName(ctx, runID, attemptIDs, artifactName)
 	if err != nil {
 		log.Error("Error artifact not found: %v", err)
 		ctx.HTTPError(http.StatusNotFound, "Error artifact not found")
 		return
 	}
-	if artifact.Status != actions_model.ArtifactStatusUploadConfirmed {
-		log.Error("Error artifact not found: %s", artifact.Status.ToString())
-		ctx.HTTPError(http.StatusNotFound, "Error artifact not found")
-		return
-	}
 
 	respData := GetSignedArtifactURLResponse{}
 
@@ -671,16 +694,15 @@ func (r *artifactV4Routes) downloadArtifact(ctx *ArtifactContext) {
 	if !ok {
 		return
 	}
-
-	// get artifact by name
-	artifact, err := r.getArtifactByName(ctx, task.Job.RunID, task.Job.RunAttemptID, artifactName)
-	if err != nil {
-		log.Error("Error artifact not found: %v", err)
-		ctx.HTTPError(http.StatusNotFound, "Error artifact not found")
+	attemptIDs, ok := readableArtifactAttemptIDs(ctx, task)
+	if !ok {
 		return
 	}
-	if artifact.Status != actions_model.ArtifactStatusUploadConfirmed {
-		log.Error("Error artifact not found: %s", artifact.Status.ToString())
+
+	// get artifact by name
+	artifact, err := r.getDownloadableArtifactByName(ctx, task.Job.RunID, attemptIDs, artifactName)
+	if err != nil {
+		log.Error("Error artifact not found: %v", err)
 		ctx.HTTPError(http.StatusNotFound, "Error artifact not found")
 		return
 	}
@@ -704,7 +726,7 @@ func (r *artifactV4Routes) deleteArtifact(ctx *ArtifactContext) {
 	}
 
 	// get artifact by name
-	artifact, err := r.getArtifactByName(ctx, runID, ctx.ActionTask.Job.RunAttemptID, req.Name)
+	artifact, err := r.getOwnAttemptArtifactByName(ctx, runID, ctx.ActionTask.Job.RunAttemptID, req.Name)
 	if err != nil {
 		log.Error("Error artifact not found: %v", err)
 		ctx.HTTPError(http.StatusNotFound, "Error artifact not found")

tests/integration/api_actions_artifact_test.go

@@ -583,6 +583,10 @@ jobs:
 		t.Run("testActionRunAttemptArtifactV4", func(t *testing.T) {
 			testActionRunAttemptArtifactV4(t, repo, session, runner)
 		})
+
+		t.Run("testPartialRerunArtifactInheritance", func(t *testing.T) {
+			testPartialRerunArtifactInheritance(t, user2, token, repo, session, runner)
+		})
 	})
 }
 
@@ -627,6 +631,107 @@ func testActionRunAttemptArtifactV3(t *testing.T, repo *repo_model.Repository, s
 	assert.Equal(t, strings.Repeat("D", 32), sharedContent2)
 }
 
+func testPartialRerunArtifactInheritance(t *testing.T, user *user_model.User, token string, repo *repo_model.Repository, session *TestSession, runner *mockRunner) {
+	wfTreePath := ".gitea/workflows/partial-rerun-artifact.yml"
+	wfFileContent := `name: partial-rerun-artifact
+on:
+  workflow_dispatch:
+jobs:
+  job1:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo 'job1'
+  job2:
+    runs-on: ubuntu-latest
+    needs: job1
+    steps:
+      - run: echo 'job2'
+`
+	opts := getWorkflowCreateFileOptions(user, repo.DefaultBranch, "create "+wfTreePath, wfFileContent)
+	createWorkflowFile(t, token, user.Name, repo.Name, wfTreePath, opts)
+
+	req := NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/%s/actions/run?workflow=%s", repo.OwnerName, repo.Name, "partial-rerun-artifact.yml"), map[string]string{
+		"ref": "refs/heads/main",
+	})
+	session.MakeRequest(t, req, http.StatusSeeOther)
+
+	// job1 uploads the artifacts and succeeds
+	task1 := runner.fetchTask(t)
+	_, job1, run := getTaskAndJobAndRunByTaskID(t, task1.Id)
+	taskToken1 := task1.Context.GetFields()["gitea_runtime_token"].GetStringValue()
+	uploadTestArtifactFileV4(t, run.ID, job1.ID, taskToken1, "job1-only", strings.Repeat("A", 32))
+	uploadTestArtifactFileV4(t, run.ID, job1.ID, taskToken1, "job1-shared", strings.Repeat("B", 32))
+	// a v3 artifact is one row per file, so this one spans two rows
+	uploadTestArtifactFile(t, run.ID, taskToken1, "job1-v3", "a.txt", strings.Repeat("D", 32))
+	uploadTestArtifactFile(t, run.ID, taskToken1, "job1-v3", "b.txt", strings.Repeat("E", 32))
+	runner.execTask(t, task1, &mockTaskOutcome{result: runnerv1.Result_RESULT_SUCCESS})
+
+	// job2 fails
+	task2 := runner.fetchTask(t)
+	_, job2, _ := getTaskAndJobAndRunByTaskID(t, task2.Id)
+	runner.execTask(t, task2, &mockTaskOutcome{result: runnerv1.Result_RESULT_FAILURE})
+
+	// re-run only the failed job, so job1 is passed through and never uploads its artifacts again
+	req = NewRequest(t, "POST", fmt.Sprintf("/%s/%s/actions/runs/%d/rerun-failed", repo.OwnerName, repo.Name, run.ID))
+	session.MakeRequest(t, req, http.StatusOK)
+
+	task3 := runner.fetchTask(t)
+	_, job3, _ := getTaskAndJobAndRunByTaskID(t, task3.Id)
+	require.Equal(t, job2.JobID, job3.JobID)
+	require.NotEqual(t, job2.RunAttemptID, job3.RunAttemptID)
+	taskToken3 := task3.Context.GetFields()["gitea_runtime_token"].GetStringValue()
+
+	// the new attempt inherits what the previous attempt uploaded
+	assert.ElementsMatch(t, []string{"job1-only", "job1-shared"}, listArtifactNamesForRunV4(t, run.ID, job3.ID, taskToken3))
+	assert.Equal(t, strings.Repeat("A", 32), downloadArtifactContentV4ByTask(t, run.ID, job3.ID, taskToken3, "job1-only"))
+	assert.Contains(t, listArtifactNamesForRun(t, run.ID, taskToken3), "job1-v3")
+
+	// a pending upload of this attempt must not shadow the confirmed copy it inherited
+	createTestArtifactV4(t, run.ID, job3.ID, taskToken3, "job1-only")
+	assert.Equal(t, strings.Repeat("A", 32), downloadArtifactContentV4ByTask(t, run.ID, job3.ID, taskToken3, "job1-only"))
+
+	// both rows of the inherited v3 artifact are readable
+	inheritedV3 := getArtifactDownloadItemsForRun(t, run.ID, taskToken3, "job1-v3")
+	require.Len(t, inheritedV3, 2)
+	assert.Equal(t, strings.Repeat("D", 32), downloadArtifactItemContent(t, taskToken3, inheritedV3[0]))
+
+	// uploading an inherited name in this attempt shadows the inherited artifact
+	inheritedSharedID := listArtifactIDForRunV4(t, run.ID, job3.ID, taskToken3, "job1-shared")
+	require.Len(t, listArtifactsByIDV4(t, run.ID, job3.ID, inheritedSharedID, taskToken3), 1)
+	uploadTestArtifactFileV4(t, run.ID, job3.ID, taskToken3, "job1-shared", strings.Repeat("C", 32))
+	assert.ElementsMatch(t, []string{"job1-only", "job1-shared"}, listArtifactNamesForRunV4(t, run.ID, job3.ID, taskToken3))
+	assert.Equal(t, strings.Repeat("C", 32), downloadArtifactContentV4ByTask(t, run.ID, job3.ID, taskToken3, "job1-shared"))
+
+	// a shadowed artifact is not listed by id either: a download resolves by name
+	assert.Empty(t, listArtifactsByIDV4(t, run.ID, job3.ID, inheritedSharedID, taskToken3))
+
+	// the shadowed v3 artifact is dropped as a whole, its b.txt row must not survive next to the new a.txt
+	uploadTestArtifactFile(t, run.ID, taskToken3, "job1-v3", "a.txt", strings.Repeat("F", 32))
+	shadowedV3 := getArtifactDownloadItemsForRun(t, run.ID, taskToken3, "job1-v3")
+	require.Len(t, shadowedV3, 1)
+	assert.Equal(t, strings.Repeat("F", 32), downloadArtifactItemContent(t, taskToken3, shadowedV3[0]))
+
+	runner.execTask(t, task3, &mockTaskOutcome{result: runnerv1.Result_RESULT_SUCCESS})
+}
+
+func getArtifactDownloadItemsForRun(t *testing.T, runID int64, taskToken, artifactName string) []downloadArtifactResponseItem {
+	t.Helper()
+
+	req := NewRequest(t, "GET", fmt.Sprintf("/api/actions_pipeline/_apis/pipelines/workflows/%d/artifacts/%x/download_url?itemPath=%s", runID, md5.Sum([]byte(artifactName)), artifactName)).
+		AddTokenAuth(taskToken)
+	resp := MakeRequest(t, req, http.StatusOK)
+	return DecodeJSON(t, resp, &downloadArtifactResponse{}).Value
+}
+
+func downloadArtifactItemContent(t *testing.T, taskToken string, item downloadArtifactResponseItem) string {
+	t.Helper()
+
+	idx := strings.Index(item.ContentLocation, "/api/actions_pipeline/_apis/pipelines/")
+	require.NotEqual(t, -1, idx)
+	req := NewRequest(t, "GET", item.ContentLocation[idx:]).AddTokenAuth(taskToken)
+	return MakeRequest(t, req, http.StatusOK).Body.String()
+}
+
 func uploadTestArtifactFile(t *testing.T, runID int64, authToken, artifactName, fileName, content string) {
 	t.Helper()
 

tests/integration/api_actions_artifact_v4_test.go

@@ -947,7 +947,24 @@ func testActionRunAttemptArtifactV4(t *testing.T, repo *repo_model.Repository, s
 	assert.Equal(t, strings.Repeat("D", 32), downloadRepoArtifactV4Content(t, session, sharedArtifactsResp.Entries[1].ArchiveDownloadURL))
 }
 
-func uploadTestArtifactFileV4(t *testing.T, runID, jobID int64, authToken, artifactName, content string) {
+func downloadArtifactContentV4ByTask(t *testing.T, runID, jobID int64, taskToken, artifactName string) string {
+	t.Helper()
+
+	req := NewRequestWithBody(t, "POST", "/twirp/github.actions.results.api.v1.ArtifactService/GetSignedArtifactURL", toProtoJSON(&actions.GetSignedArtifactURLRequest{
+		Name:                    artifactName,
+		WorkflowRunBackendId:    strconv.FormatInt(runID, 10),
+		WorkflowJobRunBackendId: strconv.FormatInt(jobID, 10),
+	})).AddTokenAuth(taskToken)
+	resp := MakeRequest(t, req, http.StatusOK)
+	var urlResp actions.GetSignedArtifactURLResponse
+	require.NoError(t, protojson.Unmarshal(resp.Body.Bytes(), &urlResp))
+	require.NotEmpty(t, urlResp.SignedUrl)
+
+	return MakeRequest(t, NewRequest(t, "GET", urlResp.SignedUrl), http.StatusOK).Body.String()
+}
+
+// createTestArtifactV4 only creates the artifact record, leaving it pending until it is uploaded and finalized
+func createTestArtifactV4(t *testing.T, runID, jobID int64, authToken, artifactName string) string {
 	t.Helper()
 
 	req := NewRequestWithBody(t, "POST", "/twirp/github.actions.results.api.v1.ArtifactService/CreateArtifact", toProtoJSON(&actions.CreateArtifactRequest{
@@ -958,11 +975,17 @@ func uploadTestArtifactFileV4(t *testing.T, runID, jobID int64, authToken, artif
 		MimeType:                wrapperspb.String("application/zip"),
 	})).AddTokenAuth(authToken)
 	resp := MakeRequest(t, req, http.StatusOK)
-	var uploadResp actions.CreateArtifactResponse
-	require.NoError(t, protojson.Unmarshal(resp.Body.Bytes(), &uploadResp))
-	require.True(t, uploadResp.Ok)
+	var createResp actions.CreateArtifactResponse
+	require.NoError(t, protojson.Unmarshal(resp.Body.Bytes(), &createResp))
+	require.True(t, createResp.Ok)
+	return createResp.SignedUploadUrl
+}
 
-	req = NewRequestWithBody(t, "PUT", uploadResp.SignedUploadUrl+"&comp=appendBlock", strings.NewReader(content))
+func uploadTestArtifactFileV4(t *testing.T, runID, jobID int64, authToken, artifactName, content string) {
+	t.Helper()
+
+	signedUploadURL := createTestArtifactV4(t, runID, jobID, authToken, artifactName)
+	req := NewRequestWithBody(t, "PUT", signedUploadURL+"&comp=appendBlock", strings.NewReader(content))
 	MakeRequest(t, req, http.StatusCreated)
 
 	sum := sha256.Sum256([]byte(content))
@@ -973,30 +996,59 @@ func uploadTestArtifactFileV4(t *testing.T, runID, jobID int64, authToken, artif
 		WorkflowRunBackendId:    strconv.FormatInt(runID, 10),
 		WorkflowJobRunBackendId: strconv.FormatInt(jobID, 10),
 	})).AddTokenAuth(authToken)
-	resp = MakeRequest(t, req, http.StatusOK)
+	resp := MakeRequest(t, req, http.StatusOK)
 	var finalizeResp actions.FinalizeArtifactResponse
 	require.NoError(t, protojson.Unmarshal(resp.Body.Bytes(), &finalizeResp))
 	require.True(t, finalizeResp.Ok)
 }
 
+func listArtifactsForRunV4(t *testing.T, taskToken string, req *actions.ListArtifactsRequest) []*actions.ListArtifactsResponse_MonolithArtifact {
+	t.Helper()
+
+	httpReq := NewRequestWithBody(t, "POST", "/twirp/github.actions.results.api.v1.ArtifactService/ListArtifacts", toProtoJSON(req)).AddTokenAuth(taskToken)
+	resp := MakeRequest(t, httpReq, http.StatusOK)
+	var listResp actions.ListArtifactsResponse
+	require.NoError(t, protojson.Unmarshal(resp.Body.Bytes(), &listResp))
+	return listResp.Artifacts
+}
+
 func listArtifactNamesForRunV4(t *testing.T, runID, jobID int64, taskToken string) []string {
 	t.Helper()
 
-	req := NewRequestWithBody(t, "POST", "/twirp/github.actions.results.api.v1.ArtifactService/ListArtifacts", toProtoJSON(&actions.ListArtifactsRequest{
+	artifacts := listArtifactsForRunV4(t, taskToken, &actions.ListArtifactsRequest{
 		WorkflowRunBackendId:    strconv.FormatInt(runID, 10),
 		WorkflowJobRunBackendId: strconv.FormatInt(jobID, 10),
-	})).AddTokenAuth(taskToken)
-	resp := MakeRequest(t, req, http.StatusOK)
-	var listResp actions.ListArtifactsResponse
-	require.NoError(t, protojson.Unmarshal(resp.Body.Bytes(), &listResp))
+	})
 
-	names := make([]string, 0, len(listResp.Artifacts))
-	for _, item := range listResp.Artifacts {
+	names := make([]string, 0, len(artifacts))
+	for _, item := range artifacts {
 		names = append(names, item.Name)
 	}
 	return names
 }
 
+func listArtifactIDForRunV4(t *testing.T, runID, jobID int64, taskToken, artifactName string) int64 {
+	t.Helper()
+
+	artifacts := listArtifactsForRunV4(t, taskToken, &actions.ListArtifactsRequest{
+		NameFilter:              wrapperspb.String(artifactName),
+		WorkflowRunBackendId:    strconv.FormatInt(runID, 10),
+		WorkflowJobRunBackendId: strconv.FormatInt(jobID, 10),
+	})
+	require.Len(t, artifacts, 1)
+	return artifacts[0].DatabaseId
+}
+
+func listArtifactsByIDV4(t *testing.T, runID, jobID, artifactID int64, taskToken string) []*actions.ListArtifactsResponse_MonolithArtifact {
+	t.Helper()
+
+	return listArtifactsForRunV4(t, taskToken, &actions.ListArtifactsRequest{
+		IdFilter:                wrapperspb.Int64(artifactID),
+		WorkflowRunBackendId:    strconv.FormatInt(runID, 10),
+		WorkflowJobRunBackendId: strconv.FormatInt(jobID, 10),
+	})
+}
+
 func downloadRepoArtifactV4Content(t *testing.T, session *TestSession, archiveDownloadURL string) string {
 	t.Helper()