# https://codeberg.org/ziglang/zig/pulls/35809

From: Eric Joldasov <bratishkaerik@landless-city.net>
Subject: [PATCH] Resolve relative install directories against install prefix

This fixes a regression introduced on the `master` branch in commit
0505318efe0d2757a344dded9ae1607f948f7511
(PR https://codeberg.org/ziglang/zig/pulls/35428).

In Zig 0.16 and earlier, overriding install sub-directories (such as
`--prefix-lib-dir`) with a relative path correctly resolved them
against the "install prefix". The mentioned PR changed this behavior
(though this was not mentioned in its description), causing relative
path overrides to resolve against the "current working directory"
instead.

This commit restores the old behavior and brings the logic back in line
with existing build system conventions (CMake, Autotools, Meson):

1. Absolute paths are used as-is.
2. Relative paths are resolved relative to the install
   prefix path, rather than CWD.

Ecosystem context:
https://github.com/mesonbuild/meson/pull/9903

Signed-off-by: Eric Joldasov <bratishkaerik@landless-city.net>
---
 lib/compiler/Maker.zig | 38 ++++++++++++++++++++++++++------------
 1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/lib/compiler/Maker.zig b/lib/compiler/Maker.zig
index ad73ac16272d..20884225b3d7 100644
--- a/lib/compiler/Maker.zig
+++ b/lib/compiler/Maker.zig
@@ -631,20 +631,34 @@ pub fn main(init: process.Init.Minimal) !void {
         .sub_path = "zig-out",
     };
 
-    const install_lib_path: Path = if (override_lib_dir) |cwd_relative| .{
-        .root_dir = .cwd(),
-        .sub_path = cwd_relative,
-    } else try install_prefix_path.join(arena, "lib");
+    // Standard installation convention (matching CMake, Autotools, and Meson):
+    // 1. Absolute paths => used as-is.
+    // 2. Relative paths => used as relative to the install prefix (NOT CWD).
+    //
+    // REF: https://github.com/mesonbuild/meson/pull/9903
+    const install_lib_path: Path = if (override_lib_dir) |lib_dir|
+        if (Dir.path.isAbsolute(lib_dir)) .{
+            .root_dir = .cwd(),
+            .sub_path = lib_dir,
+        } else try install_prefix_path.join(arena, lib_dir)
+    else
+        try install_prefix_path.join(arena, "lib");
 
-    const install_bin_path: Path = if (override_bin_dir) |cwd_relative| .{
-        .root_dir = .cwd(),
-        .sub_path = cwd_relative,
-    } else try install_prefix_path.join(arena, "bin");
+    const install_bin_path: Path = if (override_bin_dir) |bin_dir|
+        if (Dir.path.isAbsolute(bin_dir)) .{
+            .root_dir = .cwd(),
+            .sub_path = bin_dir,
+        } else try install_prefix_path.join(arena, bin_dir)
+    else
+        try install_prefix_path.join(arena, "bin");
 
-    const install_include_path: Path = if (override_include_dir) |cwd_relative| .{
-        .root_dir = .cwd(),
-        .sub_path = cwd_relative,
-    } else try install_prefix_path.join(arena, "include");
+    const install_include_path: Path = if (override_include_dir) |include_dir|
+        if (Dir.path.isAbsolute(include_dir)) .{
+            .root_dir = .cwd(),
+            .sub_path = include_dir,
+        } else try install_prefix_path.join(arena, include_dir)
+    else
+        try install_prefix_path.join(arena, "include");
 
     const now = Io.Clock.Timestamp.now(io, .awake);