fix: classify a cancelled step as an interruption, not a failure (#1095)

`reportStepError` reported every step error as FAILURE, including a `context.Canceled` from a docker file-command read cancelled at job finalization — non-deterministic red CI. Classify `context.Canceled` as an interruption instead (deferring to the job context), so a genuine cancel reports cancelled and a stray teardown cancellation is ignored, never a failure.

---------

Co-authored-by: bircni <bircni@icloud.com>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1095
Reviewed-by: bircni <bircni@icloud.com>

act/runner/cancellation_test.go

@@ -283,3 +283,30 @@ func TestPostStepsContextDeadlinePreservesJobError(t *testing.T) {
 	require.NoError(t, postCtx.Err(), "post context must not carry the expired deadline")
 	assert.ErrorIs(t, common.JobError(postCtx), assert.AnError, "the timeout job error must be preserved")
 }
+
+// reportStepError must treat a context.Canceled (e.g. a teardown-cancelled read) as an
+// interruption, never a job failure.
+func TestReportStepErrorTreatsCancelAsInterruption(t *testing.T) {
+	rc := &RunContext{}
+
+	// stray read cancellation while the job context is live: ignored, not a failure
+	live := common.WithJobErrorContainer(context.Background())
+	reportStepError(live, rc, context.Canceled)
+	require.NoError(t, common.JobError(live))
+	assert.False(t, rc.jobFailed)
+	assert.False(t, rc.jobCancelled)
+
+	// genuine job cancellation: recorded as cancelled, still not a failure
+	cancelled, cancel := context.WithCancel(common.WithJobErrorContainer(context.Background()))
+	cancel()
+	reportStepError(cancelled, rc, context.Canceled)
+	require.NoError(t, common.JobError(cancelled))
+	assert.False(t, rc.jobFailed)
+	assert.True(t, rc.jobCancelled)
+
+	// a real error still fails the job
+	failed := common.WithJobErrorContainer(context.Background())
+	reportStepError(failed, rc, assert.AnError)
+	require.ErrorIs(t, common.JobError(failed), assert.AnError)
+	assert.True(t, rc.jobFailed)
+}

act/runner/job_executor.go

@@ -10,6 +10,7 @@ import (
 	"context"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -56,9 +57,15 @@ type jobInfo interface {
 	result(result string)
 }
 
-// reportStepError emits the GitHub Actions ##[error] annotation and records
-// the error against the job so the job is reported as failed.
+// reportStepError records a step error so the job is reported failed — except a
+// cancellation, which is an interruption, not a failure.
 func reportStepError(ctx context.Context, rc *RunContext, err error) {
+	if errors.Is(err, context.Canceled) {
+		// Defer to the job context: a genuine cancel reports cancelled, a stray teardown
+		// cancellation on a live ctx is ignored — never a step FAILURE.
+		rc.markInterrupted(ctx.Err())
+		return
+	}
 	common.Logger(ctx).Errorf("##[error]%v", err)
 	common.SetJobError(ctx, err)
 	rc.markFailed()