Filter out type=gha cache entries and print warning

GHA cache backend is redundant with Depot's built-in caching and can cause
'Our services aren't available right now' errors. This change filters out
--cache-from and --cache-to entries with type=gha and prints a warning
message to inform users that this cache type is being ignored.

Fixes DEP-3118

Co-authored-by: jacob <jacob@depot.dev>

Author: cursoragent

pkg/buildx/bake/bake.go

@@ -1269,10 +1269,10 @@ func toBuildOpt(t *Target, inp *Input) (*build.Options, error) {
 	}
 
 	if t.CacheFrom != nil {
-		bo.CacheFrom = buildflags.CreateCaches(t.CacheFrom)
+		bo.CacheFrom = buildflags.CreateCaches(buildflags.FilterGHACaches(t.CacheFrom, "cache-from"))
 	}
 	if t.CacheTo != nil {
-		bo.CacheTo = buildflags.CreateCaches(t.CacheTo)
+		bo.CacheTo = buildflags.CreateCaches(buildflags.FilterGHACaches(t.CacheTo, "cache-to"))
 	}
 
 	bo.Exports, _, err = buildflags.CreateExports(t.Outputs)

pkg/buildx/bake/buildflags/cache.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/csv"
 	"encoding/json"
+	"fmt"
 	"maps"
 	"os"
 	"strconv"
@@ -265,3 +266,48 @@ func addAwsCredentials(ci *CacheOptionsEntry) {
 		ci.Attrs["session_token"] = credentials.SessionToken
 	}
 }
+
+// FilterGHACaches filters out GitHub Actions cache entries (type=gha) and prints
+// a warning message when they are detected. The GHA cache backend is redundant
+// with Depot's built-in caching and can cause "Our services aren't available
+// right now" errors.
+func FilterGHACaches(entries CacheOptions, direction string) CacheOptions {
+	var filtered CacheOptions
+	var foundGHA bool
+
+	for _, entry := range entries {
+		if entry.Type == "gha" {
+			foundGHA = true
+			continue
+		}
+		filtered = append(filtered, entry)
+	}
+
+	if foundGHA {
+		fmt.Fprintf(os.Stderr, "WARNING: Ignoring %s with type=gha: GitHub Actions cache is redundant with Depot's built-in caching\n", direction)
+	}
+
+	return filtered
+}
+
+// FilterGHACacheEntries filters out GitHub Actions cache entries (type=gha) from
+// client.CacheOptionsEntry slices and prints a warning message when they are detected.
+// This is used by the build command which uses docker/buildx types directly.
+func FilterGHACacheEntries(entries []client.CacheOptionsEntry, direction string) []client.CacheOptionsEntry {
+	var filtered []client.CacheOptionsEntry
+	var foundGHA bool
+
+	for _, entry := range entries {
+		if entry.Type == "gha" {
+			foundGHA = true
+			continue
+		}
+		filtered = append(filtered, entry)
+	}
+
+	if foundGHA {
+		fmt.Fprintf(os.Stderr, "WARNING: Ignoring %s with type=gha: GitHub Actions cache is redundant with Depot's built-in caching\n", direction)
+	}
+
+	return filtered
+}

pkg/buildx/commands/build.go

@@ -632,13 +632,13 @@ func validateBuildOptions(in *buildOptions) (map[string]build.Options, error) {
 	if err != nil {
 		return nil, err
 	}
-	opts.CacheFrom = cacheImports
+	opts.CacheFrom = depotbuildflags.FilterGHACacheEntries(cacheImports, "--cache-from")
 
 	cacheExports, err := buildflags.ParseCacheEntry(in.cacheTo)
 	if err != nil {
 		return nil, err
 	}
-	opts.CacheTo = cacheExports
+	opts.CacheTo = depotbuildflags.FilterGHACacheEntries(cacheExports, "--cache-to")
 
 	allow, err := buildflags.ParseEntitlements(in.allow)
 	if err != nil {