Bug 1802405 - Prepend mozillabuild msys2 to path only for the build. r=glandium

This reverts bug 1801826 and instead prepends the msys2 path only for
the build, which is a bit more sensible.

This allows us to remove the existing warning from old_configure, since
that can't happen now.

Differential Revision: https://phabricator.services.mozilla.com/D163073

build/mach_initialize.py

@@ -116,11 +116,9 @@ def _maybe_activate_mozillabuild_environment():
 
     paths_to_add = [mozillabuild_msys_tools_path, mozillabuild / "bin"]
     existing_paths = [Path(p) for p in os.environ.get("PATH", "").split(os.pathsep)]
-    # It's important that we prepend to the path rather than append,
-    # in case mach is getting called from another msys2 environment.
     for new_path in paths_to_add:
         if new_path not in existing_paths:
-            os.environ["PATH"] = f"{new_path}{os.pathsep}" + os.environ["PATH"]
+            os.environ["PATH"] += f"{os.pathsep}{new_path}"
 
 
 def initialize(topsrcdir):

build/moz.configure/init.configure

@@ -794,6 +794,12 @@ def target_is_windows(target):
         return True
 
 
+@depends(host)
+def host_is_windows(host):
+    if host.kernel == "WINNT":
+        return True
+
+
 set_define("_WINDOWS", target_is_windows)
 set_define("WIN32", target_is_windows)
 set_define("XP_WIN", target_is_windows)
@@ -823,6 +829,12 @@ def target_is_osx(target):
         return True
 
 
+@depends(host)
+def host_is_osx(host):
+    if host.os == "OSX":
+        return True
+
+
 set_define("XP_MACOSX", target_is_osx)
 
 
@@ -1120,6 +1132,23 @@ def mozbuild_state_path(path, _):
     return normalize_path(os.path.expanduser(os.path.join("~", ".mozbuild")))
 
 
+@depends("MOZILLABUILD", shell, host_is_windows)
+@imports(_from="pathlib", _import="Path")
+def mozillabuild_bin_paths(mozillabuild, shell, host_is_windows):
+    paths = []
+    if not mozillabuild or not host_is_windows:
+        return paths
+    paths.append(os.path.dirname(shell))
+    paths.append(str(Path(mozillabuild[0]) / "bin"))
+    return paths
+
+
+@depends(mozillabuild_bin_paths)
+@imports("os")
+def prefer_mozillabuild_path(mozillabuild_bin_paths):
+    return mozillabuild_bin_paths + os.environ["PATH"].split(os.pathsep)
+
+
 # A template providing a shorthand for setting a variable. The created
 # option will only be settable with imply_option.
 # It is expected that a project-specific moz.configure will call imply_option

build/moz.configure/old.configure

@@ -11,6 +11,7 @@ m4 = check_prog(
         "gm4",
         "m4",
     ),
+    paths=prefer_mozillabuild_path,
 )
 
 
@@ -121,11 +122,11 @@ def old_configure_for(old_configure_path, extra_env=None):
     @depends(
         prepare_configure,
         prepare_configure_options,
+        prefer_mozillabuild_path,
         altered_path,
         extra_env,
         build_environment,
         old_configure_path,
-        "MOZILLABUILD",
         awk,
         m4,
         shell,
@@ -147,17 +148,23 @@ def old_configure_for(old_configure_path, extra_env=None):
     def old_configure(
         prepare_configure,
         prepare_configure_options,
+        prefer_mozillabuild_path,
         altered_path,
         extra_env,
         build_env,
         old_configure,
-        mozillabuild,
         awk,
         m4,
         shell,
     ):
         # Use prepare_configure to make lint happy
         prepare_configure
+
+        if altered_path:
+            path = altered_path
+        else:
+            path = os.pathsep.join(prefer_mozillabuild_path)
+
         refresh = True
         if os.path.exists(old_configure):
             mtime = os.path.getmtime(old_configure)
@@ -183,6 +190,7 @@ def old_configure_for(old_configure_path, extra_env=None):
             env["M4"] = m4
             env["AWK"] = awk
             env["AC_MACRODIR"] = os.path.join(build_env.topsrcdir, "build", "autoconf")
+            env["PATH"] = path
 
             try:
                 script = subprocess.check_output(
@@ -199,17 +207,6 @@ def old_configure_for(old_configure_path, extra_env=None):
                     env=env,
                 )
             except CalledProcessError as exc:
-                # Autoconf on win32 may break due to a bad $PATH.  Let the user know
-                # their $PATH is suspect.
-                if mozillabuild:
-                    mozillabuild_path = normsep(mozillabuild[0])
-                    sh_path = normsep(find_program("sh"))
-                    if mozillabuild_path not in sh_path:
-                        log.warning(
-                            "The '{}msys/bin' directory is not first in $PATH. "
-                            "This may cause autoconf to fail. ($PATH is currently "
-                            "set to: {})".format(mozillabuild_path, os.environ["PATH"])
-                        )
                 die("autoconf exited with return code {}".format(exc.returncode))
 
             if not script:
@@ -259,8 +256,7 @@ def old_configure_for(old_configure_path, extra_env=None):
                 log_size = os.path.getsize(config_log.baseFilename)
                 break
 
-        if altered_path:
+        env["PATH"] = path
-            env["PATH"] = altered_path
 
         if extra_env:
             env.update(extra_env)

build/moz.configure/toolchain.configure

@@ -68,12 +68,6 @@ with only_when(target_is_osx):
         return value[0]
 
 
-@depends(host)
-def host_is_osx(host):
-    if host.os == "OSX":
-        return True
-
-
 with only_when(host_is_osx | target_is_osx):
     # MacOS SDK
     # =========
@@ -531,12 +525,6 @@ def get_vc_paths(topsrcdir):
         yield (Version(install["installationVersion"]), tools_path)
 
 
-@depends(host)
-def host_is_windows(host):
-    if host.kernel == "WINNT":
-        return True
-
-
 option(
     "--with-visual-studio-version",
     nargs=1,
@@ -662,13 +650,17 @@ def rust_search_path(rust_path, search_order, original_path):
 
 # As a workaround until bug 1516228 and bug 1516253 are fixed, set the PATH
 # variable for the build to contain the toolchain search path.
-@depends(vc_toolchain_search_path)
+#
+# FIXME(bug 1802573): The two bugs above are fixed, do we still need that?
+#
+# Prepend the mozilla-build msys2 path, since otherwise we can get mismatched
+# cygwin dll errors during configure if we get called from another msys2
+# environment, see bug 1801826.
+@depends(mozillabuild_bin_paths, vc_toolchain_search_path)
 @imports("os")
-@imports(_from="os", _import="environ")
+def altered_path(mozillabuild_bin_paths, vc_toolchain_search_path):
-def altered_path(vc_toolchain_search_path):
+    altered_path = mozillabuild_bin_paths + list(vc_toolchain_search_path)
-    path = environ["PATH"].split(os.pathsep)
+    for p in os.environ["PATH"].split(os.pathsep):
-    altered_path = list(vc_toolchain_search_path)
-    for p in path:
         if p not in altered_path:
             altered_path.append(p)
     return os.pathsep.join(altered_path)

moz.configure

@@ -189,6 +189,7 @@ set_config("ENABLE_UNIFIED_BUILD", True, when="--disable-unified-build")
 
 include("build/moz.configure/bootstrap.configure")
 
+
 # The execution model of the configure sandbox doesn't allow for
 # check_prog to use bootstrap_search_path directly because check_prog
 # comes first, so we use a trick to allow it. Uses of check_prog
@@ -516,7 +517,7 @@ add_old_configure_assignment("CLANG_PLUGIN", clang_plugin_path)
 
 # Awk detection
 # ==============================================================
-awk = check_prog("AWK", ("gawk", "mawk", "nawk", "awk"))
+awk = check_prog("AWK", ("gawk", "mawk", "nawk", "awk"), paths=prefer_mozillabuild_path)
 
 # Until the AWK variable is not necessary in old-configure