From fdebdd31111aec5b739341a2a9ac29ca353032d9 Mon Sep 17 00:00:00 2001
From: LN Liberda <lauren@selfisekai.rocks>
Date: Thu, 6 Mar 2025 23:03:47 +0100
Subject: [PATCH] Compile: Pass absolute --zig-lib-dir to child processes

Bug: https://github.com/ziglang/zig/issues/22119
---
 build.zig                         |  2 +-
 lib/std/Build/Cache/Directory.zig | 11 +++++++++++
 lib/std/Build/Step/Compile.zig    |  2 +-
 test/tests.zig                    |  2 +-
 4 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/build.zig b/build.zig
index 9a52a35275..96c60852da 100644
--- a/build.zig
+++ b/build.zig
@@ -1366,7 +1366,7 @@ fn generateLangRef(b: *std.Build) std.Build.LazyPath {
             // in a temporary directory
             "--cache-root", b.cache_root.path orelse ".",
         });
-        cmd.addArgs(&.{ "--zig-lib-dir", b.fmt("{}", .{b.graph.zig_lib_directory}) });
+        cmd.addArgs(&.{ "--zig-lib-dir", b.graph.zig_lib_directory.absolutePath(b.allocator) catch @panic("failed to make --zig-lib-dir absolute") });
         cmd.addArgs(&.{"-i"});
         cmd.addFileArg(b.path(b.fmt("doc/langref/{s}", .{entry.name})));
 
diff --git a/lib/std/Build/Cache/Directory.zig b/lib/std/Build/Cache/Directory.zig
index 4de1cc18f1..ec8e3de518 100644
--- a/lib/std/Build/Cache/Directory.zig
+++ b/lib/std/Build/Cache/Directory.zig
@@ -72,3 +72,14 @@ pub fn format(
 pub fn eql(self: Directory, other: Directory) bool {
     return self.handle.fd == other.handle.fd;
 }
+
+pub fn absolutePath(self: Directory, allocator: Allocator) ![]u8 {
+    if (self.path) |p| {
+        if (fs.path.isAbsolute(p)) {
+            return @constCast(p);
+        }
+        return fs.path.join(allocator, &.{ try std.process.getCwdAlloc(allocator), p });
+    } else {
+        return std.process.getCwdAlloc(allocator);
+    }
+}
diff --git a/lib/std/Build/Step/Compile.zig b/lib/std/Build/Step/Compile.zig
index 616e8f76b4..c3e531bedf 100644
--- a/lib/std/Build/Step/Compile.zig
+++ b/lib/std/Build/Step/Compile.zig
@@ -1693,7 +1693,7 @@ fn getZigArgs(compile: *Compile, fuzz: bool) ![][]const u8 {
     const opt_zig_lib_dir = if (compile.zig_lib_dir) |dir|
         dir.getPath2(b, step)
     else if (b.graph.zig_lib_directory.path) |_|
-        b.fmt("{}", .{b.graph.zig_lib_directory})
+        try b.graph.zig_lib_directory.absolutePath(b.allocator)
     else
         null;
 
diff --git a/test/tests.zig b/test/tests.zig
index 7ef5a33a03..45cff2c5c4 100644
--- a/test/tests.zig
+++ b/test/tests.zig
@@ -1771,7 +1771,7 @@ pub fn addIncrementalTests(b: *std.Build, test_step: *Step) !void {
 
         run.addArg(b.graph.zig_exe);
         run.addFileArg(b.path("test/incremental/").path(b, entry.path));
-        run.addArgs(&.{ "--zig-lib-dir", b.fmt("{}", .{b.graph.zig_lib_directory}) });
+        run.addArgs(&.{ "--zig-lib-dir", try b.graph.zig_lib_directory.absolutePath(b.allocator) });
 
         run.addCheck(.{ .expect_term = .{ .Exited = 0 } });