diff --git a/cpython-windows/build.py b/cpython-windows/build.py index bc97cd57..3f9298aa 100644 --- a/cpython-windows/build.py +++ b/cpython-windows/build.py @@ -224,8 +224,20 @@ def find_vswhere(): def find_vs_path(path, msvc_version): + """ + Attempts to find 'path' by invoking vswhere to identify where the + given msvc_version is installed. + + vswhere is akin to things like 'pkg-config', it's an executable + that can be invoked to retrieve parameters of visual studio code + installations on the host machine. + """ vswhere = find_vswhere() + # vswhere uses a math-like range expression for specifying the + # major release numbers. + # 16 = Visual Studio 2019, + # 17 = Visual Studio 2022, if msvc_version == "2019": version = "[16,17)" elif msvc_version == "2022": @@ -233,26 +245,42 @@ def find_vs_path(path, msvc_version): else: raise ValueError(f"unsupported Visual Studio version: {msvc_version}") - p = subprocess.check_output( - [ - str(vswhere), - # Visual Studio 2019. - "-version", - version, - "-property", - "installationPath", - "-products", - "*", - ] - ) + # Assemble the command line into an argv list for a subprocess + # call, so if the command fails we can tell the user what command + # we tried and enable them to potentially investigate further. + cmdline = [ + str(vswhere), + "-version", + version, + "-property", + "installationPath", + "-prerelease", + "-products", + "*", + ] + p = subprocess.check_output(cmdline) + if not p: + # add quotes around any of the terms with spaces in them, so that + # the user can copy-and-paste the command. + cmdline = ['"%s"' % term if " " in term else term for term in cmdline] + print("could not find visual studio (using '%s')" % cmdline) + sys.exit(1) # Strictly speaking the output may not be UTF-8. - p = pathlib.Path(p.strip().decode("utf-8")) - - p = p / path + p = p.strip().decode("utf-8") + + # vswhere can potentially report multiple installed versions, + # one per line. The above 'strip' will have removed any + # trailing newlines, so if there is still a newline, there + # is more than one option. + if "\n" in p: # more than one line + print("found multiple matching instances of visual studio %s:" % msvc_version) + print(p) + sys.exit(1) + p = pathlib.Path(p, path) if not p.exists(): - print("%s does not exist" % p) + print("%s does not exist for vs%s" % (p, msvc_version)) sys.exit(1) return p