From: Brett Cannon <brett@python.org>
Date: Fri, 5 Sep 2025 22:48:16 +0000 (-0700)
Subject: GH-95952: Require setting `HOSTRUNNER` when cross compiling for WASI (#138203)
X-Git-Tag: v3.15.0a1~472
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bde12919522b0c40fd9eaa2b2681695166497aba;p=thirdparty%2FPython%2Fcpython.git

GH-95952: Require setting `HOSTRUNNER` when cross compiling for WASI (#138203)

macOS by default doesn't have the requisite CLI tools to make a default value easy. Plus Tools/wasm/wasi takes care of setting HOSTRUNNER.
---

diff --git a/Misc/NEWS.d/next/Build/2025-08-27-11-32-02.gh-issue-95952.KSymc7.rst b/Misc/NEWS.d/next/Build/2025-08-27-11-32-02.gh-issue-95952.KSymc7.rst
new file mode 100644
index 000000000000..0e4b4615342b
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2025-08-27-11-32-02.gh-issue-95952.KSymc7.rst
@@ -0,0 +1,5 @@
+When cross-compiling for WASI, require that the HOSTRUNNER environment
+variable be explicitly set.
+
+This was needed as macOS lacks the appropriate CLI tools to set a reasonable
+default.
diff --git a/configure b/configure
index bdeab8a6d126..7dd333690a3a 100755
--- a/configure
+++ b/configure
@@ -7903,8 +7903,10 @@ then :
   as_fn_append HOSTRUNNER " --experimental-wasm-memory64"
 fi
      ;; #(
-              WASI) :
-    HOSTRUNNER='wasmtime run --wasm max-wasm-stack=16777216 --wasi preview2=n --env PYTHONPATH=/$(shell realpath --relative-to $(abs_srcdir) $(abs_builddir))/$(shell cat pybuilddir.txt):/Lib --dir $(srcdir)::/' ;; #(
+  WASI) :
+
+      as_fn_error $? "HOSTRUNNER must be set when cross-compiling to WASI" "$LINENO" 5
+     ;; #(
   *) :
     HOSTRUNNER=''
    ;;
diff --git a/configure.ac b/configure.ac
index 991fa40746be..8fc8f1eced20 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1636,10 +1636,9 @@ then
       HOSTRUNNER="$NODE"
       AS_VAR_IF([host_cpu], [wasm64], [AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-memory64"])])
     ],
-    dnl TODO: support other WASI runtimes
-    dnl wasmtime starts the process with "/" as CWD. For OOT builds add the
-    dnl directory containing _sysconfigdata to PYTHONPATH.
-    [WASI], [HOSTRUNNER='wasmtime run --wasm max-wasm-stack=16777216 --wasi preview2=n --env PYTHONPATH=/$(shell realpath --relative-to $(abs_srcdir) $(abs_builddir))/$(shell cat pybuilddir.txt):/Lib --dir $(srcdir)::/'],
+    [WASI], [
+      AC_MSG_ERROR([HOSTRUNNER must be set when cross-compiling to WASI])
+    ],
     [HOSTRUNNER='']
   )
 fi