gitlab: Implement ChecksByChange with per-job pipeline detail

internal/forge/gitlab/checks_report.go

@@ -2,18 +2,93 @@ package gitlab
 
 import (
 	"context"
+	"fmt"
 
 	"go.abhg.dev/gs/internal/forge"
+	"go.abhg.dev/gs/internal/gateway/gitlab"
 )
 
-// ChecksByChange reports per-change rolled-up and per-run check state
-// for each of the given changes.
+// rollupFromPipelineStatus collapses a GitLab pipeline status into the
+// forge rollup taxonomy. Canceled/manual/skipped pipelines are
+// user-initiated non-failures and roll up as passed. Unknown statuses
+// default to pending — GitLab adds new pipeline states over time and
+// reporting them as pending is safer than reporting them as failed.
+func rollupFromPipelineStatus(status string) forge.ChecksRollupState {
+	switch status {
+	case gitlab.PipelineStatusSuccess,
+		gitlab.PipelineStatusSkipped,
+		gitlab.PipelineStatusCanceled,
+		gitlab.PipelineStatusManual:
+		return forge.ChecksRollupPassed
+	case gitlab.PipelineStatusFailed:
+		return forge.ChecksRollupFailed
+	case gitlab.PipelineStatusCreated,
+		gitlab.PipelineStatusWaitingForResource,
+		gitlab.PipelineStatusPreparing,
+		gitlab.PipelineStatusPending,
+		gitlab.PipelineStatusRunning,
+		gitlab.PipelineStatusScheduled:
+		return forge.ChecksRollupPending
+	default:
+		return forge.ChecksRollupPending
+	}
+}
+
+// ChecksByChange reports per-change rolled-up and per-job pipeline
+// state for each of the given merge requests.
 //
-// TODO: real implementation lands on a follow-up branch.
-// This stub returns one nil per id to satisfy the [forge.Repository]
-// interface while the schema branch lands standalone.
+// One MergeRequestGet + (when a pipeline exists) one PipelineJobsList
+// call per MR. The job list is reported in pipeline order (stages
+// first, then job order within stages) which is the most useful order
+// for both UI surfaces and tooltips.
 func (r *Repository) ChecksByChange(
-	_ context.Context, ids []forge.ChangeID,
+	ctx context.Context, ids []forge.ChangeID,
 ) ([]*forge.ChecksReport, error) {
-	return make([]*forge.ChecksReport, len(ids)), nil
+	out := make([]*forge.ChecksReport, len(ids))
+	for i, id := range ids {
+		checks, err := r.changeChecks(ctx, id)
+		if err != nil {
+			return nil, fmt.Errorf("change %v: %w", id, err)
+		}
+		out[i] = checks
+	}
+	return out, nil
+}
+
+func (r *Repository) changeChecks(
+	ctx context.Context, id forge.ChangeID,
+) (*forge.ChecksReport, error) {
+	mrID := mustMR(id)
+	mr, _, err := r.client.MergeRequestGet(ctx, r.repoID, mrID.Number, nil)
+	if err != nil {
+		return nil, fmt.Errorf("get merge request: %w", err)
+	}
+
+	if mr.HeadPipeline == nil {
+		return &forge.ChecksReport{Rollup: forge.ChecksRollupNone}, nil
+	}
+
+	out := &forge.ChecksReport{
+		Rollup: rollupFromPipelineStatus(mr.HeadPipeline.Status),
+		URL:    mr.HeadPipeline.WebURL,
+	}
+
+	if mr.HeadPipeline.ID == 0 {
+		return out, nil
+	}
+
+	jobs, _, err := r.client.PipelineJobsList(ctx, r.repoID, mr.HeadPipeline.ID)
+	if err != nil {
+		return nil, fmt.Errorf("list pipeline jobs: %w", err)
+	}
+
+	out.Runs = make([]forge.CheckRun, 0, len(jobs))
+	for _, j := range jobs {
+		out.Runs = append(out.Runs, forge.CheckRun{
+			Name:  j.Name,
+			State: j.Status, // already lowercase per GitLab
+			URL:   j.WebURL,
+		})
+	}
+	return out, nil
 }

internal/forge/gitlab/checks_report_test.go

@@ -0,0 +1,36 @@
+package gitlab
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"go.abhg.dev/gs/internal/forge"
+	"go.abhg.dev/gs/internal/gateway/gitlab"
+)
+
+func TestRollupFromPipelineStatus(t *testing.T) {
+	tests := []struct {
+		status string
+		want   forge.ChecksRollupState
+	}{
+		{gitlab.PipelineStatusSuccess, forge.ChecksRollupPassed},
+		{gitlab.PipelineStatusSkipped, forge.ChecksRollupPassed},
+		// Canceled and manual are user-initiated non-failures.
+		{gitlab.PipelineStatusCanceled, forge.ChecksRollupPassed},
+		{gitlab.PipelineStatusManual, forge.ChecksRollupPassed},
+		{gitlab.PipelineStatusFailed, forge.ChecksRollupFailed},
+		{gitlab.PipelineStatusPending, forge.ChecksRollupPending},
+		{gitlab.PipelineStatusRunning, forge.ChecksRollupPending},
+		{gitlab.PipelineStatusCreated, forge.ChecksRollupPending},
+		{gitlab.PipelineStatusPreparing, forge.ChecksRollupPending},
+		{gitlab.PipelineStatusWaitingForResource, forge.ChecksRollupPending},
+		{gitlab.PipelineStatusScheduled, forge.ChecksRollupPending},
+		{"unknown", forge.ChecksRollupPending},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.status, func(t *testing.T) {
+			assert.Equal(t, tt.want, rollupFromPipelineStatus(tt.status))
+		})
+	}
+}

internal/gateway/gitlab/api.go

@@ -228,6 +228,31 @@ func (c *Client) CommitStatusList(
 	return response, resp, nil
 }
 
+// PipelineJobsList lists the jobs of a pipeline, in pipeline order.
+//
+// GitLab API:
+// https://docs.gitlab.com/api/jobs/#list-pipeline-jobs
+func (c *Client) PipelineJobsList(
+	ctx context.Context,
+	projectID int64,
+	pipelineID int64,
+) ([]*Job, *Response, error) {
+	var response []*Job
+	resp, err := c.get(
+		ctx,
+		fmt.Sprintf(
+			"projects/%d/pipelines/%d/jobs",
+			projectID, pipelineID,
+		),
+		nil,
+		&response,
+	)
+	if err != nil {
+		return nil, resp, err
+	}
+	return response, resp, nil
+}
+
 // MergeRequestNoteCreate creates a merge request note.
 //
 // GitLab API:
@@ -545,6 +570,17 @@ type MergeRequest struct {
 type Pipeline struct {
 	ID     int64  `json:"id"`
 	Status string `json:"status"`
+	WebURL string `json:"web_url,omitempty"`
+}
+
+// Job is a single CI job within a pipeline.
+//
+// GitLab jobs API:
+// https://docs.gitlab.com/api/jobs/
+type Job struct {
+	Name   string `json:"name"`
+	Status string `json:"status"`
+	WebURL string `json:"web_url,omitempty"`
 }
 
 // CommitStatus matches the subset of GitLab commit status fields