Prevents providers mirror from crashing with bad lock file (#1985)

Signed-off-by: Andrew Hayes <andrew.hayes@harness.io>

internal/command/e2etest/providers_mirror_test.go

@@ -84,3 +84,47 @@ func testOpenTofuProvidersMirror(t *testing.T, fixture string) {
 		t.Errorf("unexpected files in result\n%s", diff)
 	}
 }
+
+// this test is based on testOpenTofuProvidersMirror above.
+func TestOpenTofuProvidersMirrorBadLockfile(t *testing.T) {
+	// This test reaches out to registry.opentofu.org to download the
+	// template and null providers, so it can only run if network access is
+	// allowed.
+	skipIfCannotAccessNetwork(t)
+
+	outputDir := t.TempDir()
+	t.Logf("creating mirror directory in %s", outputDir)
+
+	fixturePath := filepath.Join("testdata", "tofu-providers-mirror-with-bad-lock-file")
+	tf := e2e.NewBinary(t, tofuBin, fixturePath)
+
+	stdout, stderr, err := tf.Run("providers", "mirror", outputDir)
+	if err == nil {
+		t.Fatalf("expected error: %s\nstdout:\n%s\nstderr:\n%s", err, stdout, stderr)
+	}
+
+	var want []string
+	var got []string
+	walkErr := filepath.Walk(outputDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil // we only care about leaf files for this test
+		}
+		relPath, err := filepath.Rel(outputDir, path)
+		if err != nil {
+			return err
+		}
+		got = append(got, filepath.ToSlash(relPath))
+		return nil
+	})
+	if walkErr != nil {
+		t.Fatal(walkErr)
+	}
+	sort.Strings(got)
+
+	if diff := cmp.Diff(want, got); diff != "" {
+		t.Errorf("unexpected files in result\n%s", diff)
+	}
+}

internal/command/e2etest/testdata/tofu-providers-mirror-with-bad-lock-file/.terraform.lock.hcl

@@ -0,0 +1,8 @@
+# This file is maintained automatically by "tofu init".
+# Manual edits may be lost in future updates.
+
+provider "registry.opentofu.org/hashicorp/tfcoremocka" {
+  version = "0.2.0"
+  hashes = ["zh:"
+  ]
+}

internal/command/e2etest/testdata/tofu-providers-mirror-with-bad-lock-file/main.tf

@@ -0,0 +1,7 @@
+terraform {
+  required_providers {
+    tfcoremock = {
+      source  = "tfcoremock"
+    }
+  }
+}

internal/command/providers_mirror.go

@@ -164,6 +164,14 @@ func (c *ProvidersMirrorCommand) Run(args []string) int {
 		}
 		selected := candidates.Newest()
 		if !lockedDeps.Empty() {
+			if lockedDeps.Provider(provider) == nil {
+				diags = diags.Append(tfdiags.Sourceless(
+					tfdiags.Error,
+					"Provider not found in lockfile",
+					fmt.Sprintf("Failed to find %s in the lock file", provider.String()),
+				))
+				continue
+			}
 			selected = lockedDeps.Provider(provider).Version()
 			c.Ui.Output(fmt.Sprintf("  - Selected v%s to match dependency lock file", selected.String()))
 		} else if len(constraintsStr) > 0 {