From d2a338f57d099bb3838d42031ecc88cdb4ad0317 Mon Sep 17 00:00:00 2001
From: Jeffrey Chen <jeffreychen@microsoft.com>
Date: Wed, 10 Dec 2025 20:56:25 +0000
Subject: [PATCH] Implement TargetResourceResolver for containerAppTarget
 instead of using `SupportsDelayedProvisioning()`

---
 cli/azd/pkg/project/service_target.go         | 12 +++---
 .../project/service_target_containerapp.go    | 41 +++++++++++++++++++
 2 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/cli/azd/pkg/project/service_target.go b/cli/azd/pkg/project/service_target.go
index 2ed744f289d..5ce1feae9cd 100644
--- a/cli/azd/pkg/project/service_target.go
+++ b/cli/azd/pkg/project/service_target.go
@@ -147,13 +147,15 @@ func (st ServiceTargetKind) IgnoreFile() string {
 	}
 }
 
-// SupportsDelayedProvisioning returns true if the service target kind
-// supports delayed provisioning resources at deployment time, otherwise false.
+// SupportsDelayedProvisioning returns true if the service target supports provisioning
+// resources during deployment when they don't exist yet.
 //
-// As an example, ContainerAppTarget is able to provision the container app as part of deployment,
-// and thus returns true.
+// Deprecated: Use TargetResourceResolver interface for custom resource resolution instead.
+// Container Apps supports delayed provisioning but implements TargetResourceResolver to
+// provide better error messages when resources are missing in non-bicep deployment scenarios.
+// Retained only for AKS backward compatibility.
 func (st ServiceTargetKind) SupportsDelayedProvisioning() bool {
-	return st == AksTarget || st == ContainerAppTarget
+	return st == AksTarget
 }
 
 func checkResourceType(resource *environment.TargetResource, expectedResourceType azapi.AzureResourceType) error {
diff --git a/cli/azd/pkg/project/service_target_containerapp.go b/cli/azd/pkg/project/service_target_containerapp.go
index 3529bc3e3bf..b598b0177a7 100644
--- a/cli/azd/pkg/project/service_target_containerapp.go
+++ b/cli/azd/pkg/project/service_target_containerapp.go
@@ -6,6 +6,7 @@ package project
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"log"
 	"os"
@@ -16,6 +17,7 @@ import (
 	"github.com/azure/azure-dev/cli/azd/pkg/async"
 	"github.com/azure/azure-dev/cli/azd/pkg/azapi"
 	"github.com/azure/azure-dev/cli/azd/pkg/azure"
+	"github.com/azure/azure-dev/cli/azd/pkg/azureutil"
 	"github.com/azure/azure-dev/cli/azd/pkg/containerapps"
 	"github.com/azure/azure-dev/cli/azd/pkg/environment"
 	"github.com/azure/azure-dev/cli/azd/pkg/exec"
@@ -395,6 +397,45 @@ func (at *containerAppTarget) validateTargetResource(
 	return nil
 }
 
+// ResolveTargetResource implements TargetResourceResolver for containerAppTarget.
+// It attempts to find an existing container app resource. If not found, it returns a partial
+// target resource (with resource group but no resource name) to support bicep-based deployments
+// that provision the container app on-demand.
+func (at *containerAppTarget) ResolveTargetResource(
+	ctx context.Context,
+	subscriptionId string,
+	serviceConfig *ServiceConfig,
+	defaultResolver func() (*environment.TargetResource, error),
+) (*environment.TargetResource, error) {
+	targetResource, err := defaultResolver()
+	if err == nil {
+		return targetResource, nil
+	}
+
+	var resourceNotFoundError *azureutil.ResourceNotFoundError
+	if errors.As(err, &resourceNotFoundError) {
+		resourceGroupTemplate := serviceConfig.ResourceGroupName
+		if resourceGroupTemplate.Empty() {
+			resourceGroupTemplate = serviceConfig.Project.ResourceGroupName
+		}
+
+		resourceGroupName, rgErr := at.resourceManager.GetResourceGroupName(ctx, subscriptionId, resourceGroupTemplate)
+		if rgErr != nil {
+			return nil, err
+		}
+
+		// Return partial target resource to enable bicep-based deployments
+		return environment.NewTargetResource(
+			subscriptionId,
+			resourceGroupName,
+			"",
+			string(azapi.AzureResourceTypeContainerApp),
+		), nil
+	}
+
+	return nil, err
+}
+
 func (at *containerAppTarget) addPreProvisionChecks(ctx context.Context, serviceConfig *ServiceConfig) error {
 	// Attempt to retrieve the target resource for the current service
 	// This allows the resource deployment to detect whether or not to pull existing container image during