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Incorrect docs for mimetypes.MimeTypes.types_map #115075
Description
cpython/Doc/library/mimetypes.rst
Lines 213 to 218 in 13eb521
Notice
They are initialized by
common_typesandtypes_map.
The same is applicable for MimeTypes.types_map_inv. Try
import mimetypes
mimetypes.init()
mimetypes.types_map[".ae1"] = "application/pers.added"
db = mimetypes.MimeTypes()
print(db.types_map[True].get(".ae1"))it reports
None
Accordingly to the docs I would expect application/pers.added. It can be achieved by commenting out the mimetypes.init() call.
I think, behavior changed when #49213 was fixed, but docs have not been updated.
I see some reason in the documented behavior. Perhaps mimetypes.init() should be more flexible and support both ways to set types_map: from the global dictionary and from the internal data, but likely it should be discussed on the pyhton-ideas mailing list first.
Linked PRs
- gh-115075: Clarify docs for types_map and types_map_inv on mimetypes.MimeTypes #136761
- gh-115075: Fix info about initialization of mimetypes.MimeTypes attributes #150691
- [3.15] gh-115075: Fix info about initialization of mimetypes.MimeTypes attributes (GH-150691) #156625
- [3.14] gh-115075: Fix info about initialization of mimetypes.MimeTypes attributes (GH-150691) #156626
- [3.13] gh-115075: Fix info about initialization of mimetypes.MimeTypes attributes (GH-150691) #156627
Activity
pythongh-115075: Fix info about initialization of mimetypes.MimeTypes…
serhiy-storchaka commentedon May 31, 2026
This behavior was so long, that it is now considered a new norm. We should just document it. Any changes of the behavior should be considered a new feature.
gh-115075: Fix info about initialization of mimetypes.MimeTypes attri…
[3.13] gh-115075: Fix info about initialization of mimetypes.MimeType…
[3.14] gh-115075: Fix info about initialization of mimetypes.MimeType…
[3.15] gh-115075: Fix info about initialization of mimetypes.MimeType…
pythongh-115075: Fix info about initialization of mimetypes.MimeTypes…