httpcaddyfile: Fix default issuers when email provided

If `tls <email>` is used, we should apply that to all applicable default issuers, not drop them. This refactoring applies implicit ACME issuer settings from the tls directive to all default ACME issuers, like ZeroSSL.

We also consolidate some annoying logic and improve config validity checks.

Ref: https://caddy.community/t/error-obtaining-certificate-after-caddy-restart/11335/8

1 files changed, 41 insertions, 15 deletions

diff --git a/caddyconfig/httpcaddyfile/builtins.go b/caddyconfig/httpcaddyfile/builtins.go
index aa68adb..4945a81 100644
--- a/caddyconfig/httpcaddyfile/builtins.go
+++ b/caddyconfig/httpcaddyfile/builtins.go
@@ -369,31 +369,57 @@ func parseTLS(h Helper) ([]ConfigValue, error) {
 		})
 	}
 
+	// some tls subdirectives are shortcuts that implicitly configure issuers, and the
+	// user can also configure issuers explicitly using the issuer subdirective; the
+	// logic to support both would likely be complex, or at least unintuitive
 	if len(issuers) > 0 && (acmeIssuer != nil || internalIssuer != nil) {
-		// some tls subdirectives are shortcuts that implicitly configure issuers, and the
-		// user can also configure issuers explicitly using the issuer subdirective; the
-		// logic to support both would likely be complex, or at least unintuitive
 		return nil, h.Err("cannot mix issuer subdirective (explicit issuers) with other issuer-specific subdirectives (implicit issuers)")
 	}
-	for _, issuer := range issuers {
-		configVals = append(configVals, ConfigValue{
-			Class: "tls.cert_issuer",
-			Value: issuer,
-		})
-	}
-	if acmeIssuer != nil {
-		configVals = append(configVals, ConfigValue{
-			Class: "tls.cert_issuer",
-			Value: disambiguateACMEIssuer(acmeIssuer),
-		})
+	if acmeIssuer != nil && internalIssuer != nil {
+		return nil, h.Err("cannot create both ACME and internal certificate issuers")
 	}
-	if internalIssuer != nil {
+
+	// now we should either have: explicitly-created issuers, or an implicitly-created
+	// ACME or internal issuer, or no issuers at all
+	switch {
+	case len(issuers) > 0:
+		for _, issuer := range issuers {
+			configVals = append(configVals, ConfigValue{
+				Class: "tls.cert_issuer",
+				Value: issuer,
+			})
+		}
+
+	case acmeIssuer != nil:
+		// implicit ACME issuers (from various subdirectives) - use defaults; there might be more than one
+		defaultIssuers := caddytls.DefaultIssuers()
+
+		// if a CA endpoint was set, override multiple implicit issuers since it's a specific one
+		if acmeIssuer.CA != "" {
+			defaultIssuers = []certmagic.Issuer{acmeIssuer}
+		}
+
+		for _, issuer := range defaultIssuers {
+			switch iss := issuer.(type) {
+			case *caddytls.ACMEIssuer:
+				issuer = acmeIssuer
+			case *caddytls.ZeroSSLIssuer:
+				iss.ACMEIssuer = acmeIssuer
+			}
+			configVals = append(configVals, ConfigValue{
+				Class: "tls.cert_issuer",
+				Value: issuer,
+			})
+		}
+
+	case internalIssuer != nil:
 		configVals = append(configVals, ConfigValue{
 			Class: "tls.cert_issuer",
 			Value: internalIssuer,
 		})
 	}
 
+	// certificate key type
 	if keyType != "" {
 		configVals = append(configVals, ConfigValue{
 			Class: "tls.key_type",