The package_version(...) function MUST accept either a single package name or a list of package names. However, as of ac3eed5ef083de6a387dbb9a0d916a7854c67632, passing a list of package names to package_version causes the following error (at least on Windows):
RuntimeError: 'path_helpers)$' is not recognized as an internal or external command,
operable program or batch file.
Cause
When a list of package names is passed to package_version, the package names are joined into a regular expression string using the | character (i.e., the "or" operator). However, the | character is also used as a ["pipe" operator][1] on the command line. Therefore, the regular expression string must be quoted.
Unfortunately, at least on Windows, there does not seem to be a way to force the subprocess.* commands to force quoting an argument (see subprocess.list2cmdline to try converting a list of args to the corresponding argument string).
Workaround
This issue can be worked around by explicitly adding a space into the regular expression, which causes the argument to be quoted.
The
package_version(...)function MUST accept either a single package name or a list of package names. However, as of ac3eed5ef083de6a387dbb9a0d916a7854c67632, passing a list of package names topackage_versioncauses the following error (at least on Windows):Cause
When a list of package names is passed to
package_version, the package names are joined into a regular expression string using the|character (i.e., the "or" operator). However, the|character is also used as a ["pipe" operator][1] on the command line. Therefore, the regular expression string must be quoted.Unfortunately, at least on Windows, there does not seem to be a way to force the
subprocess.*commands to force quoting an argument (seesubprocess.list2cmdlineto try converting a list of args to the corresponding argument string).Workaround
This issue can be worked around by explicitly adding a space into the regular expression, which causes the argument to be quoted.