suppressing Project id vs project number diff in forwardingRule.target

.changelog/12606.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+compute: Allowed Service attachment with Project Number to be used as ForwardingRule.Target 
+```

google/services/compute/resource_compute_forwarding_rule.go

@@ -497,7 +497,7 @@ mode or when creating external forwarding rule with IPv6.`,
 			"target": {
 				Type:             schema.TypeString,
 				Optional:         true,
-				DiffSuppressFunc: tpgresource.CompareSelfLinkRelativePaths,
+				DiffSuppressFunc: tpgresource.CompareSelfLinkRelativePathsIgnoreProjectId,
 				Description: `The URL of the target resource to receive the matched traffic.  For
 regional forwarding rules, this target must be in the same region as the
 forwarding rule. For global forwarding rules, this target must be a global

google/tpgresource/common_diff_suppress.go

@@ -95,11 +95,23 @@ func DurationDiffSuppress(k, old, new string, d *schema.ResourceData) bool {
 // has the project number instead of the project name
 func ProjectNumberDiffSuppress(_, old, new string, _ *schema.ResourceData) bool {
 	var a2, b2 string
-	reN := regexp.MustCompile("projects/\\d+")
+	re := regexp.MustCompile("projects/\\d+")
+	reN := regexp.MustCompile("projects/[^/]+")
+	replacement := []byte("projects/equal")
+	a2 = string(re.ReplaceAll([]byte(old), replacement))
+	b2 = string(reN.ReplaceAll([]byte(new), replacement))
+	return a2 == b2
+}
+
+// Suppress diffs when the value read from api
+// has the project ID instead of the project number
+func ProjectIDDiffSuppress(_, old, new string, _ *schema.ResourceData) bool {
+	var a2, b2 string
 	re := regexp.MustCompile("projects/[^/]+")
+	reN := regexp.MustCompile("projects/\\d+")
 	replacement := []byte("projects/equal")
-	a2 = string(reN.ReplaceAll([]byte(old), replacement))
-	b2 = string(re.ReplaceAll([]byte(new), replacement))
+	a2 = string(re.ReplaceAll([]byte(old), replacement))
+	b2 = string(reN.ReplaceAll([]byte(new), replacement))
 	return a2 == b2
 }
 

google/tpgresource/common_diff_suppress_test.go

@@ -69,6 +69,53 @@ func TestDurationDiffSuppress(t *testing.T) {
 	}
 }
 
+func TestProjectNumberDiffSuppress(t *testing.T) {
+	cases := map[string]struct {
+		Old, New           string
+		ExpectDiffSuppress bool
+	}{
+		"different project identifiers": {
+			Old:                "projects/1234/locations/abc/serviceAttachments/xyz",
+			New:                "projects/ten-tp/locations/abc/serviceAttachments/xyz",
+			ExpectDiffSuppress: true,
+		},
+		"different resources": {
+			Old:                "projects/1234/locations/abc/serviceAttachments/jkl",
+			New:                "projects/ten-tp/locations/abc/serviceAttachments/xyz",
+			ExpectDiffSuppress: false,
+		},
+	}
+
+	for tn, tc := range cases {
+		if ProjectNumberDiffSuppress("diffSuppress", tc.Old, tc.New, nil) != tc.ExpectDiffSuppress {
+			t.Fatalf("bad: %s, '%s' => '%s' expect %t", tn, tc.Old, tc.New, tc.ExpectDiffSuppress)
+		}
+	}
+}
+
+func TestProjectIDDiffSuppress(t *testing.T) {
+	cases := map[string]struct {
+		Old, New           string
+		ExpectDiffSuppress bool
+	}{
+		"different project identifiers": {
+			Old:                "projects/ten-tp/locations/abc/serviceAttachments/xyz",
+			New:                "projects/1234/locations/abc/serviceAttachments/xyz",
+			ExpectDiffSuppress: true,
+		},
+		"different resources": {
+			Old:                "projects/ten-tp/locations/abc/serviceAttachments/xyz",
+			New:                "projects/1234/locations/abc/serviceAttachments/jkl",
+			ExpectDiffSuppress: false,
+		},
+	}
+
+	for tn, tc := range cases {
+		if ProjectIDDiffSuppress("diffSuppress", tc.Old, tc.New, nil) != tc.ExpectDiffSuppress {
+			t.Fatalf("bad: %s, '%s' => '%s' expect %t", tn, tc.Old, tc.New, tc.ExpectDiffSuppress)
+		}
+	}
+}
 func TestEmptyOrUnsetBlockDiffSuppress(t *testing.T) {
 	cases := map[string]struct {
 		Key, Old, New      string

google/tpgresource/self_link_helpers.go

@@ -19,7 +19,7 @@ func CompareResourceNames(_, old, new string, _ *schema.ResourceData) bool {
 }
 
 // Compare only the relative path of two self links.
-func CompareSelfLinkRelativePaths(_, old, new string, _ *schema.ResourceData) bool {
+func CompareSelfLinkRelativePathsIgnoreProjectId(unused1, old, new string, unused2 *schema.ResourceData) bool {
 	oldStripped, err := GetRelativePath(old)
 	if err != nil {
 		return false
@@ -33,7 +33,24 @@ func CompareSelfLinkRelativePaths(_, old, new string, _ *schema.ResourceData) bo
 	if oldStripped == newStripped {
 		return true
 	}
+	return ProjectIDDiffSuppress(unused1, oldStripped, newStripped, unused2)
+}
+
+// Compare only the relative path of two self links.
+func CompareSelfLinkRelativePaths(_, old, new string, _ *schema.ResourceData) bool {
+	oldStripped, err := GetRelativePath(old)
+	if err != nil {
+		return false
+	}
 
+	newStripped, err := GetRelativePath(new)
+	if err != nil {
+		return false
+	}
+
+	if oldStripped == newStripped {
+		return true
+	}
 	return false
 }
 

google/tpgresource/self_link_helpers_test.go

@@ -68,6 +68,70 @@ func TestCompareSelfLinkOrResourceName(t *testing.T) {
 	}
 }
 
+func TestCompareSelfLinkRelativePathsIgnoreProjectId(t *testing.T) {
+	cases := map[string]struct {
+		Old, New string
+		Expect   bool
+	}{
+		"full path, project number": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "https://www.googleapis.com/compute/v1/projects/1234/global/networks/a-network",
+			Expect: true,
+		},
+		"partial path, project number": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "projects/1234/global/networks/a-network",
+			Expect: true,
+		},
+		"partial path, same": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "projects/your-project/global/networks/a-network",
+			Expect: true,
+		},
+		"partial path, different name": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "projects/your-project/global/networks/another-network",
+			Expect: false,
+		},
+		"partial path, different project": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "projects/another-project/global/networks/a-network",
+			Expect: false,
+		},
+		"full path, different name": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/another-network",
+			Expect: false,
+		},
+		"full path, different project": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "https://www.googleapis.com/compute/v1/projects/another-project/global/networks/a-network",
+			Expect: false,
+		},
+		"beta full path, same": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "https://www.googleapis.com/compute/beta/projects/your-project/global/networks/a-network",
+			Expect: true,
+		},
+		"beta full path, different name": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "https://www.googleapis.com/compute/beta/projects/your-project/global/networks/another-network",
+			Expect: false,
+		},
+		"beta full path, different project": {
+			Old:    "https://www.googleapis.com/compute/v1/projects/your-project/global/networks/a-network",
+			New:    "https://www.googleapis.com/compute/beta/projects/another-project/global/networks/a-network",
+			Expect: false,
+		},
+	}
+
+	for tn, tc := range cases {
+		if CompareSelfLinkRelativePathsIgnoreProjectId("", tc.Old, tc.New, nil) != tc.Expect {
+			t.Errorf("bad: %s, expected %t for old = %q and new = %q", tn, tc.Expect, tc.Old, tc.New)
+		}
+	}
+}
+
 func TestGetResourceNameFromSelfLink(t *testing.T) {
 	cases := map[string]struct {
 		SelfLink, ExpectedName string