Add patch for buildkit to fetch by commit

buildkit/Dockerfile

@@ -13,6 +13,7 @@ COPY \
 	backport-5372-sbom-args.patch \
 	backport-moby-48455-fix-riscv64-seccomp.patch \
 	containerd-arm64-v8.patch \
+	git-fetch-by-commit.patch \
 	git-no-submodules.patch \
 	mips64le.patch \
 	noclip.patch \

buildkit/Dockerfile.0.13

@@ -16,6 +16,7 @@ COPY \
 	backport-5372-sbom-args.patch \
 	backport-moby-48455-fix-riscv64-seccomp.patch \
 	containerd-arm64-v8-pre-0.15.patch \
+	git-fetch-by-commit.patch \
 	git-no-submodules.patch \
 	mips64le-pre-0.16.patch \
 	noclip.patch \

buildkit/Dockerfile.rc

@@ -11,6 +11,7 @@ ENV BUILDKIT_VERSION 0.17.0-rc2
 
 COPY \
 	containerd-arm64-v8.patch \
+	git-fetch-by-commit.patch \
 	git-no-submodules.patch \
 	mips64le.patch \
 	noclip.patch \

buildkit/Dockerfile.template

@@ -30,6 +30,7 @@ COPY \
 		"backport-5372-sbom-args.patch": { until: "0.17" },
 		"backport-moby-48455-fix-riscv64-seccomp.patch": { until: "0.17" },
 		"containerd-arm64-v8.patch": { older: { "0.15": "containerd-arm64-v8-pre-0.15.patch" } },
+		"git-fetch-by-commit.patch": { },
 		"git-no-submodules.patch": { },
 		"mips64le.patch": { older: { "0.16": "mips64le-pre-0.16.patch" } },
 		"noclip.patch": { },

buildkit/git-fetch-by-commit.patch

@@ -0,0 +1,20 @@
+Description: try fetching by commit, then regular fall back to deeper fetching
+Forwarded: no
+
+diff --git a/source/git/source.go b/source/git/source.go
+index d139942fc..700982bd6 100644
+--- a/source/git/source.go
++++ b/source/git/source.go
+@@ -459,6 +459,12 @@ func (gs *gitSourceHandler) Snapshot(ctx context.Context, g session.Group) (out
+ 		// skip fetch if commit already exists
+ 		if _, err := git.Run(ctx, "cat-file", "-e", ref+"^{commit}"); err == nil {
+ 			doFetch = false
++		} else {
++			// try fetching commit directly
++			// TODO limit to known working git hosts?
++			if _, err := git.Run(ctx, "fetch", "origin", ref+":"); err == nil {
++				doFetch = false
++			}
+ 		}
+ 	}
+