Change corefx test process (#16263)

Instead of using the `/p:CoreCLROverridePath` switch when building
corefx, to bring in coreclr, build corefx normally. This builds
against the coreclr packages that corefx has already been validated
against in the CI, so the build should always work. Then, copy
over our built coreclr bits before testing. This method is expected
to have better behavior in most breaking change scenarios.

diff --git a/tests/scripts/run-corefx-tests.py b/tests/scripts/run-corefx-tests.py
index 246ec71..7f261af 100644 (file)
--- a/tests/scripts/run-corefx-tests.py
+++ b/tests/scripts/run-corefx-tests.py
@@ -29,6 +29,8 @@ import sys
 # Globals
 ##########################################################################
 
+testing = False
+
 Corefx_url = 'https://github.com/dotnet/corefx.git'
 
 # This should be factored out of build.sh
@@ -181,6 +183,29 @@ def log(message):
 
     print '[%s]: %s' % (sys.argv[0], message)
 
+def copy_files(source_dir, target_dir):
+    """ Copy any files in the source_dir to the target_dir.
+        The copy is not recursive.
+        The directories must already exist.
+    Args:
+        source_dir (str): source directory path
+        target_dir (str): target directory path
+    Returns:
+        Nothing
+    """
+
+    global testing
+    assert os.path.isdir(source_dir)
+    assert os.path.isdir(target_dir)
+
+    for source_filename in os.listdir(source_dir):
+        source_pathname = os.path.join(source_dir, source_filename)
+        if os.path.isfile(source_pathname):
+            target_pathname = os.path.join(target_dir, source_filename)
+            log('Copy: %s => %s' % (source_pathname, target_pathname))
+            if not testing:
+                shutil.copy2(source_pathname, target_pathname)
+
 ##########################################################################
 # Main
 ##########################################################################
@@ -188,8 +213,7 @@ def log(message):
 def main(args):
     global Corefx_url
     global Unix_name_map
-
-    testing = False
+    global testing
 
     arch, ci_arch, build_type, clr_root, fx_root, fx_branch, fx_commit, env_script, no_run_tests = validate_args(
         args)
@@ -260,17 +284,44 @@ def main(args):
 
     config_args = '-Release -os:%s -buildArch:%s' % (clr_os, arch)
 
-    # Run the primary (non-test) corefx build
+    # Run the primary (non-test) corefx build. We previously passed the argument:
+    #
+    #    /p:CoreCLROverridePath=<path-to-core_root>
+    #
+    # which causes the corefx build to overwrite its built runtime with the binaries from
+    # the coreclr build. However, this often causes build failures when breaking changes are
+    # in progress (e.g., a breaking change is made in coreclr that has not yet had compensating
+    # changes made in the corefx repo). Instead, build corefx normally. This should always work
+    # since corefx is protected by a CI testing system. Then, overwrite the built corefx
+    # runtime with the runtime built in the coreclr build. The result will be that perhaps
+    # some, hopefully few, corefx tests will fail, but the builds will never fail.
 
     command = ' '.join(('build.cmd' if Is_windows else './build.sh',
-                        config_args,
-                        '-- /p:CoreCLROverridePath=%s' % core_root))
+                        config_args))
 
     log(command)
     returncode = 0 if testing else os.system(command)
     if returncode != 0:
         sys.exit(1)
 
+    # Override the built corefx runtime (which it picked up by copying from packages determined
+    # by its dependencies.props file). Note that we always build Release corefx.
+    # We must copy all files, not just the files that already exist in the corefx runtime
+    # directory. This is required so we copy over all altjit compilers.
+    # TODO: it might be cleaner to encapsulate the knowledge of how to do this in the
+    # corefx msbuild files somewhere.
+
+    fx_runtime = os.path.join(fx_root,
+                             'bin',
+                             'testhost',
+                             'netcoreapp-%s-%s-%s' % (clr_os, 'Release', arch),
+                             'shared',
+                             'Microsoft.NETCore.App',
+                             '9.9.9')
+
+    log('Updating CoreCLR: %s => %s' % (core_root, fx_runtime))
+    copy_files(core_root, fx_runtime)
+
     # Build the build-tests command line.
 
     if Is_windows: