https://github.com/python/cpython/commit/ae065f83625f3abcf75d928f405e05582fc... commit: ae065f83625f3abcf75d928f405e05582fc035b4 branch: 3.10 author: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> committer: miss-islington <31488909+miss-islington@users.noreply.github.com> date: 2021-11-23T21:02:32-08:00 summary: bpo-45616: Let py.exe distinguish between v3.1 and v3.10 (GH-29731) (cherry picked from commit f9de97aae5fe9dafb58a8099171f4a09c449f4e8) Co-authored-by: Zachary Ware <zach@python.org> files: A Misc/NEWS.d/next/Windows/2021-11-23-11-44-42.bpo-45616.K52PLZ.rst M PC/launcher.c diff --git a/Misc/NEWS.d/next/Windows/2021-11-23-11-44-42.bpo-45616.K52PLZ.rst b/Misc/NEWS.d/next/Windows/2021-11-23-11-44-42.bpo-45616.K52PLZ.rst new file mode 100644 index 0000000000000..000f2fd3cc989 --- /dev/null +++ b/Misc/NEWS.d/next/Windows/2021-11-23-11-44-42.bpo-45616.K52PLZ.rst @@ -0,0 +1,4 @@ +Fix Python Launcher's ability to distinguish between versions 3.1 and 3.10 +when either one is explicitly requested. Previously, 3.1 would be used if +3.10 was requested but not installed, and 3.10 would be used if 3.1 was +requested but 3.10 was installed. diff --git a/PC/launcher.c b/PC/launcher.c index f5b225ac08cfe..84c8a1d14ea41 100644 --- a/PC/launcher.c +++ b/PC/launcher.c @@ -542,8 +542,17 @@ find_python_by_version(wchar_t const * wanted_ver) } for (i = 0; i < num_installed_pythons; i++, ip++) { n = wcslen(ip->version); - if (n > wlen) + /* + * If wlen is greater than 1, we're probably trying to find a specific + * version and thus want an exact match: 3.1 != 3.10. Otherwise, we + * just want a prefix match. + */ + if ((wlen > 1) && (n != wlen)) { + continue; + } + if (n > wlen) { n = wlen; + } if ((wcsncmp(ip->version, wanted_ver, n) == 0) && /* bits == 0 => don't care */ ((bits == 0) || (ip->bits == bits))) {