From ee7f0f6323a12e223acd2ef565b2dcc3a7e21a7a Mon Sep 17 00:00:00 2001
From: CrazyMax <1951866+crazy-max@users.noreply.github.com>
Date: Thu, 19 Mar 2026 13:42:39 +0100
Subject: [PATCH] build: ignore empty BUILDKIT_SYNTAX overrides

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>
---
 build/opt.go | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/build/opt.go b/build/opt.go
index f7522fe87edd..287e6bef9a3d 100644
--- a/build/opt.go
+++ b/build/opt.go
@@ -298,10 +298,12 @@ func toSolveOpt(ctx context.Context, np *noderesolver.ResolvedNode, multiDriver
 	}
 
 	if v, ok := opt.BuildArgs["BUILDKIT_SYNTAX"]; ok {
-		p := strings.SplitN(strings.TrimSpace(v), " ", 2)
-		so.Frontend = "gateway.v0"
-		so.FrontendAttrs["source"] = p[0]
-		so.FrontendAttrs["cmdline"] = v
+		if cmdline := strings.TrimSpace(v); cmdline != "" {
+			p := strings.SplitN(cmdline, " ", 2)
+			so.Frontend = "gateway.v0"
+			so.FrontendAttrs["source"] = p[0]
+			so.FrontendAttrs["cmdline"] = v
+		}
 	}
 
 	if v, ok := opt.BuildArgs["BUILDKIT_MULTI_PLATFORM"]; ok {