Unintended type conversions when using disjoint_union #761
Description
Bug Description
With the breaking change of igraph version 1.4.0, igraph now respects the concrete type of attributes when setting edge or vertex attributes (#633). While I am happy that the type is respect now, the function disjoint_union does not respect the attributes' types and does some weird type conversions.
How to Reproduce this Bug
Here is a minimum working example, in which the wrong behavior of disjoint_union can be seen:
# create two graphs
g1 <- make_graph(~ B -- C, C -- D)
g2 <- make_graph(~ A -- B, E -- D)
# add an edge attribute of class POSIXct to each graph
g1 <- set.edge.attribute(g1, "date", value = as.POSIXct(c("2021-01-01 01:01:01", "2022-02-02 02:02:02")))
g2 <- set.edge.attribute(g2, "date", value = as.POSIXct(c("2021-03-03 03:03:03", "2022-04-04 04:04:04")))
# create the union of the two graphs
u <- disjoint_union(g1,g2)
# now print the structure of g1, g2, and u
str(g1)
str(g2)
str(u)You can find the corresponding output of the str(...) calls below – look for the date attribute in each of the three graphs to see that disjoint_union performs an unwanted type conversion: For g1 and g2, the class of the date attribute is POSIXct. However, for u, the class of the date attribute is num. This leads to various problems if you assume in your code that the dates are always given in POSIXct but then disjoint_union inadvertently converts them into numeric unix timestamps.
str(g1)
Class 'igraph' hidden list of 10
$ : num 3
$ : logi FALSE
$ : num [1:2] 1 2
$ : num [1:2] 0 1
$ : num [1:2] 0 1
$ : num [1:2] 0 1
$ : num [1:4] 0 0 1 2
$ : num [1:4] 0 1 2 2
$ :List of 4
..$ : num [1:3] 1 0 1
..$ : Named list()
..$ :List of 1
.. ..$ name: chr [1:3] "B" "C" "D"
..$ :List of 1
.. ..$ date: POSIXct[1:2], format: "2021-01-01 01:01:01" "2022-02-02 02:02:02"
$ :<environment: 0x55f6dc22f0f8>
str(g2)
Class 'igraph' hidden list of 10
$ : num 4
$ : logi FALSE
$ : num [1:2] 1 3
$ : num [1:2] 0 2
$ : num [1:2] 0 1
$ : num [1:2] 0 1
$ : num [1:5] 0 0 1 1 2
$ : num [1:5] 0 1 1 2 2
$ :List of 4
..$ : num [1:3] 1 0 1
..$ : Named list()
..$ :List of 1
.. ..$ name: chr [1:4] "A" "B" "E" "D"
..$ :List of 1
.. ..$ date: POSIXct[1:2], format: "2021-03-03 03:03:03" "2022-04-04 04:04:04"
$ :<environment: 0x55f6e23ae7e8>
str(u)
Class 'igraph' hidden list of 10
$ : num 7
$ : logi FALSE
$ : num [1:4] 1 2 4 6
$ : num [1:4] 0 1 3 5
$ : num [1:4] 0 1 2 3
$ : num [1:4] 0 1 2 3
$ : num [1:8] 0 0 1 2 2 3 3 4
$ : num [1:8] 0 1 2 2 3 3 4 4
$ :List of 4
..$ : num [1:3] 1 0 1
..$ : list()
..$ :List of 1
.. ..$ name: chr [1:7] "B" "C" "D" "A" ...
..$ :List of 1
.. ..$ date: num [1:4] 1.61e+09 1.64e+09 1.61e+09 1.65e+09
$ :<environment: 0x55f6df448638>
Version Information
- igraph version: 1.4.0 and 1.4.1 (according to your NEWS.md, the behavior of respecting attribute types was introduced in feat!: Allow change of attribute type when setting attribute for all vertices or edges, only attributes of length 1 or the length of the target set allowed #633 in igraph version 1.4.0)
- R version: 4.2.3
- Operating system: Debian 11
Rest of the output of sessionInfo():
Matrix products: default
BLAS: /usr/lib/x86_64-linux-gnu/atlas/libblas.so.3.10.3
LAPACK: /usr/lib/x86_64-linux-gnu/atlas/liblapack.so.3.10.3
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
[7] LC_PAPER=en_US.UTF-8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] compiler_4.2.3 tools_4.2.3 packrat_0.9.1
@hechtlC: FYI