igraph::graph_from_adjacency_matrix() will start requiring symmetric adjacency matrices with mode='undirected'

[szhorvat]

Describe the bug

graph_from_adjacency_matrix() is changing in igraph, and a future version will strictly require the input matrix to be symmetric if using mode='undirected'. This would cause some of the manynet tests to fail. If the non-symmetric input is intentional, choose a mode that is explicit about how to disambiguate between the above- and below-diagonal parts of the matrix.

Using mode='max' recovers the old behaviour and is compatible with earlier igraph.

Warning (test-make_read.R:124:3): read_ and write_ matrix works
The `adjmatrix` argument of `graph_from_adjacency_matrix()` must be symmetric with mode = "undirected" as of igraph 1.5.2.
ℹ Use mode = "max" to achieve the original behavior.
Backtrace:
     ▆
  1. ├─testthat::expect_equal(...) at test-make_read.R:124:2
  2. │ └─testthat::quasi_label(enquo(object), label, arg = "object")
  3. │   └─rlang::eval_bare(expr, quo_get_env(quo))
  4. ├─manynet::as_matrix(...)
  5. └─manynet::read_matrix(testthat::test_path("sheets", "test_matrix.csv")) at manynet/R/make_as.R:153:13
  6.   ├─manynet::as_tidygraph(as.matrix(out)) at manynet/R/make_read.R:89:2
  7.   └─manynet:::as_tidygraph.matrix(as.matrix(out)) at manynet/R/make_as.R:574:16
  8.     ├─tidygraph::as_tbl_graph(as_igraph(.data)) at manynet/R/make_as.R:597:2
  9.     ├─manynet::as_igraph(.data)
 10.     └─manynet:::as_igraph.matrix(.data) at manynet/R/make_as.R:301:13
 11.       └─igraph::graph_from_adjacency_matrix(...) at manynet/R/make_as.R:341:6

Provide system information

• R version: 4.3.1
• manynet version: Current main

To Reproduce

• Installl development version of R/igraph using devtools::install_github("igraph/rigraph").
• Run manynet test suite.
• Observe warning (will turn into error at a later time)

[henriquesposito]

@szhorvat Thank you for opening this issue and for the heads up.