From 10ad3253de4dad4675fbd84da874f2cd73cd2deb Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Mon, 18 Sep 2017 18:01:58 -0400
Subject: [PATCH] std.build: catch mistake of setting output path to build dir

closes #464
---
 std/build.zig | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/std/build.zig b/std/build.zig
index a241064a8..f2221d25f 100644
--- a/std/build.zig
+++ b/std/build.zig
@@ -937,8 +937,13 @@ pub const LibExeObjStep = struct {
         self.build_mode = mode;
     }
 
-    pub fn setOutputPath(self: &LibExeObjStep, value: []const u8) {
-        self.output_path = value;
+    pub fn setOutputPath(self: &LibExeObjStep, file_path: []const u8) {
+        self.output_path = file_path;
+
+        // catch a common mistake
+        if (mem.eql(u8, self.builder.pathFromRoot(file_path), self.builder.pathFromRoot("."))) {
+            debug.panic("setOutputPath wants a file path, not a directory\n");
+        }
     }
 
     pub fn getOutputPath(self: &LibExeObjStep) -> []const u8 {
@@ -949,8 +954,13 @@ pub const LibExeObjStep = struct {
         }
     }
 
-    pub fn setOutputHPath(self: &LibExeObjStep, value: []const u8) {
-        self.output_h_path = value;
+    pub fn setOutputHPath(self: &LibExeObjStep, file_path: []const u8) {
+        self.output_h_path = file_path;
+
+        // catch a common mistake
+        if (mem.eql(u8, self.builder.pathFromRoot(file_path), self.builder.pathFromRoot("."))) {
+            debug.panic("setOutputHPath wants a file path, not a directory\n");
+        }
     }
 
     pub fn getOutputHPath(self: &LibExeObjStep) -> []const u8 {