Keep candidate object inspection offline

internal/git/source_test.go

@@ -2,6 +2,10 @@ package git
 
 import (
 	"context"
+	"errors"
+	"os"
+	"os/exec"
+	"path/filepath"
 	"strings"
 	"testing"
 )
@@ -28,6 +32,47 @@ func TestInspectTaggedSourceSupportsLightweightAndAnnotatedTags(t *testing.T) {
 	}
 }
 
+func TestCandidateObjectReadsStayLocalInPartialClones(t *testing.T) {
+	fixture := newRemoteFixture(t)
+	gitRun(t, fixture.work, "config", "uploadpack.allowFilter", "true")
+	blob := strings.TrimSpace(gitText(t, fixture.work, "rev-parse", "HEAD:source.txt"))
+	for _, filter := range []string{"blob:none", "tree:0"} {
+		t.Run(filter, func(t *testing.T) {
+			repository := filepath.Join(t.TempDir(), "partial")
+			gitRun(t, fixture.work, "clone", "--filter="+filter, "--no-checkout", "file://"+filepath.ToSlash(fixture.work), repository)
+			before := gitText(t, repository, "cat-file", "--batch-all-objects", "--batch-check=%(objectname)")
+			if strings.Contains(before, blob) {
+				t.Fatal("fixture contains the filtered blob")
+			}
+			gitRun(t, repository, "config", "remote.origin.url", "ssh://releasekit-test.invalid/source")
+			attempts := filepath.Join(t.TempDir(), "attempts")
+			transport := filepath.Join(t.TempDir(), "ssh")
+			if err := os.WriteFile(transport, []byte("#!/bin/sh\nprintf 'remote accessed\\n' >> \"$RELEASEKIT_GIT_ATTEMPTS\"\nexit 1\n"), 0o755); err != nil {
+				t.Fatal(err)
+			}
+			t.Setenv("GIT_SSH_COMMAND", transport)
+			t.Setenv("RELEASEKIT_GIT_ATTEMPTS", attempts)
+			t.Setenv("GIT_NO_LAZY_FETCH", "0")
+			t.Setenv("GIT_ALLOW_PROTOCOL", "ssh")
+			if _, err := ReadTree(t.Context(), repository, fixture.commit); err == nil {
+				t.Fatal("tree inspection succeeded with unavailable objects")
+			}
+			_, err := ReadBlob(t.Context(), repository, blob)
+			var exitError *exec.ExitError
+			if !errors.As(err, &exitError) {
+				t.Fatalf("blob error %v lost its Git process cause", err)
+			}
+			if data, err := os.ReadFile(attempts); !errors.Is(err, os.ErrNotExist) {
+				t.Fatalf("object inspection invoked remote transport: %q, %v", data, err)
+			}
+			after := gitText(t, repository, "cat-file", "--batch-all-objects", "--batch-check=%(objectname)")
+			if before != after {
+				t.Fatal("object inspection populated the object database")
+			}
+		})
+	}
+}
+
 func TestInspectTaggedSourceReportsDirtyCheckoutAndReadCommitFile(t *testing.T) {
 	fixture := newRemoteFixture(t)
 	gitRun(t, fixture.work, "tag", "v1.2.3")