build: make it possible to pass arbitrary env vars to rustc

1 files changed, 18 insertions, 21 deletions

diff --git a/build_extra/rust/run.py b/build_extra/rust/run.py
index 36d1ab83a..7c6bea08a 100644
--- a/build_extra/rust/run.py
+++ b/build_extra/rust/run.py
@@ -1,13 +1,15 @@
 #!/usr/bin/env python
 # Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-# This file just executes its arguments, except that also adds GN_OUT_DIR and
-# CARGO_PKG_VERSION to the environ. This is for compatibility with cargo.
+
+# This file just executes its arguments, except that it allows overriding
+# environment variables using command-line arguments.
+
 import subprocess
 import sys
 import os
 import re
 
-args = sys.argv[1:]
+args = []
 env = os.environ.copy()
 
 if sys.platform == 'win32':
@@ -27,24 +29,19 @@ if sys.platform == 'win32':
 env["GN_OUT_DIR"] = os.path.abspath(".")
 assert os.path.isdir(env["GN_OUT_DIR"])
 
-# Some crates (e.g. 'typenum') generate source files and place them in the
-# directory indicated by the 'OUT_DIR' environment variable, which is normally
-# set by Cargo. We pre-generate these files and store them in the source repo.
-# Therefore, set 'OUT_DIR' so these crates can find their generated sources.
-for i, arg in enumerate(args):
-    match = re.search('--generated-source-dir=(.*)', arg)
-    if match:
-        env["OUT_DIR"] = os.path.abspath(match.group(1))
-        del args[i]
-        break
-
-# Set the CARGO_PKG_VERSION env variable if provided as an argument
-# When building with Cargo this variable is set automatically
-for i, arg in enumerate(args):
-    match = re.search('--cargo-pkg-version="?([^"]*)"?', arg)
+# Environment variables can be specified on the command line using
+# '--env=variable=value' flags. These flags are not passed through to rustc.
+# This is useful to set env vars that are normally automatically set by Cargo,
+# e.g. CARGO_PKG_NAME, CARGO_PKG_VERSION, OUT_DIR, etc.
+for arg in sys.argv[1:]:
+    match = re.search('--env=([^=]+)=(.*)', arg)
     if match:
-        env["CARGO_PKG_VERSION"] = match.group(1)
-        del args[i]
-        break
+        key, value = match.groups()
+        if key == "OUT_DIR":
+            # OUT_DIR needs to contain an absolute path.
+            value = os.path.abspath(value)
+        env[key] = value
+    else:
+        args.append(arg)
 
 sys.exit(subprocess.call(args, env=env))