fd16616 fix(mcp): validate global servers after project config errors · zut

M examples/extensions/mcp-bridge/README.md +2 -0


@@ -29,6 +29,8 @@ Like [Claude Code](https://code.claude.com/docs/en/mcp#environment-variable-expa
29	29
30	30		Expansion uses the bridge process environment after global/project configurations are merged. Defaults apply to unset variables; an explicitly empty variable stays empty. Values are expanded once, without shell execution, bare `$VAR` expansion, nested defaults, or references to sibling `env` entries. Config files are not rewritten. A missing variable without a default disables that server and reports the server, field, and variable name, never the field value; other valid servers remain available.
31	31
	32	+	If the project config cannot be read or parsed, the bridge reports that error and still expands and validates retained global servers. Servers with missing required variables are excluded in this case too.
	33	+
32	34		## Quick Start
33	35
34	36		1. Build the extension:


@@ -29,6 +29,8 @@ Like [Claude Code](https://code.claude.com/docs/en/mcp#environment-variable-expa
29		29
30	Expansion uses the bridge process environment after global/project configurations are merged. Defaults apply to unset variables; an explicitly empty variable stays empty. Values are expanded once, without shell execution, bare `$VAR` expansion, nested defaults, or references to sibling `env` entries. Config files are not rewritten. A missing variable without a default disables that server and reports the server, field, and variable name, never the field value; other valid servers remain available.	30		Expansion uses the bridge process environment after global/project configurations are merged. Defaults apply to unset variables; an explicitly empty variable stays empty. Values are expanded once, without shell execution, bare `$VAR` expansion, nested defaults, or references to sibling `env` entries. Config files are not rewritten. A missing variable without a default disables that server and reports the server, field, and variable name, never the field value; other valid servers remain available.
31		31
		32	+	If the project config cannot be read or parsed, the bridge reports that error and still expands and validates retained global servers. Servers with missing required variables are excluded in this case too.
		33	+
32	## Quick Start	34		## Quick Start
33		35
34	1. Build the extension:	36		1. Build the extension:

M examples/extensions/mcp-bridge/config.go +6 -4


@@ -74,24 +74,26 @@ func loadConfig(cwd string) (Config, error) {
74	74		return cfg, fmt.Errorf("global config %s: %w", globalPath, err)
75	75		}
76	76
	77	+	var configErrors []error
	78	+
77	79		// 2. Project config (overrides global per-server)
78	80		if cwd != "" {
79	81		projectPath := filepath.Join(cwd, ".zot", "mcp.json")
80	82		if err := mergeConfig(&cfg, projectPath); err != nil && !errors.Is(err, fs.ErrNotExist) {
81		-	return cfg, fmt.Errorf("project config %s: %w", projectPath, err)
	83	+	configErrors = append(configErrors, fmt.Errorf("project config %s: %w", projectPath, err))
82	84		}
83	85		}
84	86
85		-	var expansionErrors []error
	87	+	// Retained global servers must be expanded even if the project config failed.
86	88		for name, srv := range cfg.MCPServers {
87	89		if err := expandServerEnv(&srv); err != nil {
88	90		delete(cfg.MCPServers, name)
89		-	expansionErrors = append(expansionErrors, fmt.Errorf("server %q: %w", name, err))
	91	+	configErrors = append(configErrors, fmt.Errorf("server %q: %w", name, err))
90	92		continue
91	93		}
92	94		cfg.MCPServers[name] = srv
93	95		}
94		-	return cfg, errors.Join(expansionErrors...)
	96	+	return cfg, errors.Join(configErrors...)
95	97		}
96	98
97	99		// Expand only Claude Code's braced syntax, not shell expressions or bare $VAR.

 		return cfg, fmt.Errorf("global config %s: %w", globalPath, err)
 	}
+	var configErrors []error
 	// 2. Project config (overrides global per-server)
 	if cwd != "" {
 		projectPath := filepath.Join(cwd, ".zot", "mcp.json")
 		if err := mergeConfig(&cfg, projectPath); err != nil && !errors.Is(err, fs.ErrNotExist) {
-			return cfg, fmt.Errorf("project config %s: %w", projectPath, err)
+			configErrors = append(configErrors, fmt.Errorf("project config %s: %w", projectPath, err))
 		}
 	}
-	var expansionErrors []error
+	// Retained global servers must be expanded even if the project config failed.
 	for name, srv := range cfg.MCPServers {
 		if err := expandServerEnv(&srv); err != nil {
 			delete(cfg.MCPServers, name)
-			expansionErrors = append(expansionErrors, fmt.Errorf("server %q: %w", name, err))
+			configErrors = append(configErrors, fmt.Errorf("server %q: %w", name, err))
 			continue
 		}
 		cfg.MCPServers[name] = srv
 	}
-	return cfg, errors.Join(expansionErrors...)
+	return cfg, errors.Join(configErrors...)
 }
 // Expand only Claude Code's braced syntax, not shell expressions or bare $VAR.

M examples/extensions/mcp-bridge/env_test.go +45 -0


@@ -7,6 +7,51 @@ import (
7	7		"testing"
8	8		)
9	9
	10	+	func TestConfigEnvironmentExpansionWithProjectError(t *testing.T) {
	11	+	for _, kind := range []string{"malformed", "unreadable"} {
	12	+	t.Run(kind, func(t *testing.T) {
	13	+	t.Setenv("ZOT_HOME", t.TempDir())
	14	+	t.Setenv("MCP_TEST_VALUE", "synthetic-command")
	15	+	const absent = "MCP_TEST_PROJECT_ERROR_UNSET"
	16	+	// Setenv restores the original value after the test, including absence.
	17	+	t.Setenv(absent, "")
	18	+	if err := os.Unsetenv(absent); err != nil {
	19	+	t.Fatal(err)
	20	+	}
	21	+	writeJSON(t, filepath.Join(os.Getenv("ZOT_HOME"), "mcp.json"), `{"mcpServers":{
	22	+	"valid":{"command":"${MCP_TEST_VALUE}"},
	23	+	"invalid":{"headers":{"Authorization":"secret-prefix ${MCP_TEST_PROJECT_ERROR_UNSET}"}}
	24	+	}}`)
	25	+	project := t.TempDir()
	26	+	path := filepath.Join(project, ".zot", "mcp.json")
	27	+	if kind == "malformed" {
	28	+	writeJSON(t, path, `{`)
	29	+	} else if err := os.MkdirAll(path, 0o755); err != nil {
	30	+	// A directory produces a read error even when tests run as root.
	31	+	t.Fatal(err)
	32	+	}
	33	+	cfg, err := loadConfig(project)
	34	+	if err == nil {
	35	+	t.Fatal("expected config error")
	36	+	}
	37	+	for _, want := range []string{"project config", path, "invalid", absent} {
	38	+	if !strings.Contains(err.Error(), want) {
	39	+	t.Errorf("diagnostic missing %q: %v", want, err)
	40	+	}
	41	+	}
	42	+	if strings.Contains(err.Error(), "secret-prefix") {
	43	+	t.Error("diagnostic exposed field value")
	44	+	}
	45	+	if got := cfg.MCPServers["valid"].Command; got != "synthetic-command" {
	46	+	t.Errorf("global command = %q, want synthetic-command", got)
	47	+	}
	48	+	if _, ok := cfg.MCPServers["invalid"]; ok {
	49	+	t.Error("server with missing variable must not be retained")
	50	+	}
	51	+	})
	52	+	}
	53	+	}
	54	+
10	55		func TestConfigEnvironmentExpansion(t *testing.T) {
11	56		t.Setenv("ZOT_HOME", t.TempDir())
12	57		t.Setenv("MCP_TEST_VALUE", "synthetic\"\\token")


@@ -7,6 +7,51 @@ import (
7	"testing"	7		"testing"
8	)	8		)
9		9
		10	+	func TestConfigEnvironmentExpansionWithProjectError(t *testing.T) {
		11	+	for _, kind := range []string{"malformed", "unreadable"} {
		12	+	t.Run(kind, func(t *testing.T) {
		13	+	t.Setenv("ZOT_HOME", t.TempDir())
		14	+	t.Setenv("MCP_TEST_VALUE", "synthetic-command")
		15	+	const absent = "MCP_TEST_PROJECT_ERROR_UNSET"
		16	+	// Setenv restores the original value after the test, including absence.
		17	+	t.Setenv(absent, "")
		18	+	if err := os.Unsetenv(absent); err != nil {
		19	+	t.Fatal(err)
		20	+	}
		21	+	writeJSON(t, filepath.Join(os.Getenv("ZOT_HOME"), "mcp.json"), `{"mcpServers":{
		22	+	"valid":{"command":"${MCP_TEST_VALUE}"},
		23	+	"invalid":{"headers":{"Authorization":"secret-prefix ${MCP_TEST_PROJECT_ERROR_UNSET}"}}
		24	+	}}`)
		25	+	project := t.TempDir()
		26	+	path := filepath.Join(project, ".zot", "mcp.json")
		27	+	if kind == "malformed" {
		28	+	writeJSON(t, path, `{`)
		29	+	} else if err := os.MkdirAll(path, 0o755); err != nil {
		30	+	// A directory produces a read error even when tests run as root.
		31	+	t.Fatal(err)
		32	+	}
		33	+	cfg, err := loadConfig(project)
		34	+	if err == nil {
		35	+	t.Fatal("expected config error")
		36	+	}
		37	+	for _, want := range []string{"project config", path, "invalid", absent} {
		38	+	if !strings.Contains(err.Error(), want) {
		39	+	t.Errorf("diagnostic missing %q: %v", want, err)
		40	+	}
		41	+	}
		42	+	if strings.Contains(err.Error(), "secret-prefix") {
		43	+	t.Error("diagnostic exposed field value")
		44	+	}
		45	+	if got := cfg.MCPServers["valid"].Command; got != "synthetic-command" {
		46	+	t.Errorf("global command = %q, want synthetic-command", got)
		47	+	}
		48	+	if _, ok := cfg.MCPServers["invalid"]; ok {
		49	+	t.Error("server with missing variable must not be retained")
		50	+	}
		51	+	})
		52	+	}
		53	+	}
		54	+
10	func TestConfigEnvironmentExpansion(t *testing.T) {	55		func TestConfigEnvironmentExpansion(t *testing.T) {
11	t.Setenv("ZOT_HOME", t.TempDir())	56		t.Setenv("ZOT_HOME", t.TempDir())
12	t.Setenv("MCP_TEST_VALUE", "synthetic\"\\token")	57		t.Setenv("MCP_TEST_VALUE", "synthetic\"\\token")