Error opening .2dm and .xmdf mesh data

[95camarones]

Describe the bug
Having reopened a project containing TUFLOW .2dm mesh data I get the following error:

After that, the map display will not refresh - I can zoom but the extents do not change and turning layers on and off does not make them appear or disappear. I now get this error every time I add a .2dm. Restarting the computer does not help. The only thing that works seems to be to reinstall QGIS.

How to Reproduce
Example TUFLOW .2dm data here.

1. Add .2dm mesh.
2. Right-click on .2dm layer in layer panel and choose Properties... -> Source -> Add additional dataset and add .xmdf data.
3. Turn layer off.
4. Save project.
5. Restart QGIS or close and reopen project.
6. Turn layer back on and get following error:

Tools::TemporaryFile: Cannot create temporary file name.: unspecified iostream_category error

QGIS and OS versions

QGIS version	3.16.1-Hannover	QGIS code revision	3ecbe06
Compiled against Qt	5.14.2	Running against Qt	5.14.2
Compiled against GDAL/OGR	3.1.2	Running against GDAL/OGR	3.1.2
Compiled against GEOS	3.8.1-CAPI-1.13.3	Running against GEOS	3.8.1-CAPI-1.13.3
Compiled against SQLite	3.31.1	Running against SQLite	3.31.1
PostgreSQL Client Version	12.3	SpatiaLite Version	4.3.0a
QWT Version	6.1.4	QScintilla2 Version	2.11.4
Compiled against PROJ	6.3.2	Running against PROJ	Rel. 6.3.2, May 1st, 2020
OS Version	macOS Mojave (10.14.6)
Active python plugins	quick_map_services

Also tried on 3.10 A Coruña with same result.

[gioman]

No error on Linux and Windows, so seems a macOS only issue.

[saberraz]

Indeed...it works fine with QGIS master on Linux. CC @PeterPetrik

[PeterPetrik]

i have seen this few times, but never able to replicate it consistently. If I remember correctly, it comes from spatialindex when it tries to save temporary files when creating index.

[drf5n]

i have seen this few times, but never able to replicate it consistently. If I remember correctly, it comes from spatialindex when it tries to save temporary files when creating index.

Temporary files might be in a non-writable location #35651 (comment)

Try this in the Python console to determine the current working directory, and see if it is a good place to write files.

import os
os.getcwd()

[PeterPetrik]

https://github.com/libspatialindex/libspatialindex/blob/32ec7f99f960369b55d1eb333f2b02aab059330b/src/tools/Tools.cc#L1055

^^ this code creates a tmp file relative to current working directory on MacOS, which is on /Applications/QGIS.app/... where user cannot write

[PeterPetrik]

fixed in https://qgis.org/downloads/macos/nightly/qgis_nightly_master_20210205_032843.dmg

[drf5n]

Did commit 590b7f4 fix this?

[PeterPetrik]

nope, fixed spatialite to correctly use TMPDIR to store temporary files (https://github.com/qgis/QGIS-Mac-Packager/blob/master/qgis_deps/recipes/spatialindex/patches/temporaryfile.patch)

[drf5n]

Thanks. I thought mkstmp would use the spatialindex-XXXXXX template to create and open files like spatialindex-4dfg32, but the https://github.com/qgis/QGIS-Mac-Packager/blob/master/qgis_deps/recipes/spatialindex/patches/temporaryfile.patch code looks like it would ignore the mkstmp-opened file and open a separate file named something like $TMPDIR/spatialindex-XXXXXX

[PeterPetrik]

sorry, wrong commit :) qgis/QGIS-Mac-Packager@40ca7e8

[drf5n]

That's better with the path in the template for the call to mkstmp, so it tries to make a temp file in the given path rather than working dir.

And I was wrong about my other concern--mkstmp modifies the template string to the successful random filename, so the later call to m_pFile = new Tools::BufferedFileWriter(m_sFile, Tools::CREATE); reopens the new filename.