From 384d6844841e9f2da8f5a913c7620440f9e05ab5 Mon Sep 17 00:00:00 2001
From: Joost VandeVondele <Joost.VandeVondele@gmail.com>
Date: Tue, 18 Aug 2020 18:06:28 +0200
Subject: [PATCH] Better error message on missing curl/wget

provide clean error/warning message for missing curl/wget, sha256sum/shasum

fixes https://github.com/official-stockfish/Stockfish/issues/3025

closes https://github.com/official-stockfish/Stockfish/pull/3026

No functional change
---
 src/Makefile | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index 1f8ba455..a3feb68e 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -669,9 +669,24 @@ net:
 	@echo "Default net: $(nnuenet)"
 	$(eval nnuedownloadurl := https://tests.stockfishchess.org/api/nn/$(nnuenet))
 	$(eval curl_or_wget := $(shell if hash curl 2>/dev/null; then echo "curl -skL"; elif hash wget 2>/dev/null; then echo "wget -qO-"; fi))
-	@if test -f "$(nnuenet)"; then echo "Already available."; else echo "Downloading $(nnuedownloadurl)"; $(curl_or_wget) $(nnuedownloadurl) > $(nnuenet); fi
+	@if test -f "$(nnuenet)"; then \
+            echo "Already available."; \
+         else \
+            if [ "x$(curl_or_wget)" = "x" ]; then \
+               echo "Automatic download failed: neither curl nor wget is installed. Install one of these tools or download the net manually"; exit 1; \
+            else \
+               echo "Downloading $(nnuedownloadurl)"; $(curl_or_wget) $(nnuedownloadurl) > $(nnuenet);\
+            fi; \
+        fi;
 	$(eval shasum_command := $(shell if hash shasum 2>/dev/null; then echo "shasum -a 256 "; elif hash sha256sum 2>/dev/null; then echo "sha256sum "; fi))
-	@if [ "$(nnuenet)" != "nn-"`$(shasum_command) $(nnuenet) | cut -c1-12`".nnue" ]; then echo "Failed download or $(nnuenet) corrupted, please delete!"; exit 1; fi
+	@if [ "x$(shasum_command)" != "x" ]; then \
+	    if [ "$(nnuenet)" != "nn-"`$(shasum_command) $(nnuenet) | cut -c1-12`".nnue" ]; then \
+                echo "Failed download or $(nnuenet) corrupted, please delete!"; exit 1; \
+            fi \
+         else \
+            echo "shasum / sha256sum not found, skipping net validation"; \
+        fi
+
 
 # clean binaries and objects
 objclean:
-- 
2.39.2