On 7/19/2026 2:38 PM, varin sacha wrote:
Ok !
According to what I see, the error is occurring inside car:::Anova.lme(), 
specifically during the construction of the model matrix.

It therefore appears to be a genuine compatibility problem between the current 
CRAN versions of car (3.1-5), piecewiseSEM (2.3.1), and/or nlme (3.1-170).

The fact that you reproduced the same behavior on both Windows and FreeBSD also 
suggests that the issue is not platform-specific.

I think this would be worth reporting to the package maintainers (perhaps 
starting with car, since the traceback shows that the failure occurs inside 
Anova.lme(), while mentioning that the problem only arises after loading 
piecewiseSEM). The reproducible example you’ve provided should make it 
straightforward for them to investigate.

The current maintainers of car and piecewiseSEM packages are also copied on this thread. As a regular user, I am just wondering what's behind the change in Anova()'s behavior—specifically, what gets modified after attaching piecewiseSEM?

Best,

Jinsong


Le 19 juil. 2026 à 08:22, Jinsong Zhao <[email protected]> a écrit :

Thank for the instruction. Here is the whole outputs:

library(piecewiseSEM)
Registered S3 method overwritten by 'lme4':
   method           from
   na.action.merMod car

   This is piecewiseSEM version 2.3.0.2.


   Questions or bugs can be addressed to <[email protected]>.
library(nlme)
library(car)
Loading required package: carData
fm2 <- lme(distance ~ age + Sex, data = Orthodont, random = ~ 1)
Anova(fm2)
Error in if (random) { : the condition has length > 1
car::Anova(fm2)
Error in if (random) { : the condition has length > 1
car:::Anova.lme(fm2)
Error in if (random) { : the condition has length > 1
traceback()
8: model.frame.lme(object, data, xlev = xlev)
7: model.frame(object, data, xlev = xlev)
6: model.matrix.default(mod, data = structure(list(distance = c(26,
    25, 29, 31, 21.5, 22.5, 23, 26.5, 23, 22.5, 24, 27.5, 25.5, 27.5,
    26.5, 27, 20, 23.5, 22.5, 26, 24.5, 25.5, 27, 28.5, 22, 22, 24.5,
    26.5, 24, 21.5, 24.5, 25.5, 23, 20.5, 31, 26, 27.5, 28, 31, 31.5,
    23, 23, 23.5, 25, 21.5, 23.5, 24, 28, 17, 24.5, 26, 29.5, 22.5,
    25.5, 25.5, 26, 23, 24.5, 26, 30, 22, 21.5, 23.5, 25, 21, 20,
    21.5, 23, 21, 21.5, 24, 25.5, 20.5, 24, 24.5, 26, 23.5, 24.5,
    25, 26.5, 21.5, 23, 22.5, 23.5, 20, 21, 21, 22.5, 21.5, 22.5,
    23, 25, 23, 23, 23.5, 24, 20, 21, 22, 21.5, 16.5, 19, 19, 19.5,
    24.5, 25, 28, 28), age = c(8, 10, 12, 14, 8, 10, 12, 14, 8, 10,
    12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12,
    14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14,
    8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8,
    10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10,
    12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12,
    14, 8, 10, 12, 14, 8, 10, 12, 14, 8, 10, 12, 14), Subject = structure(c(15L,
    15L, 15L, 15L, 3L, 3L, 3L, 3L, 7L, 7L, 7L, 7L, 14L, 14L, 14L,
    14L, 2L, 2L, 2L, 2L, 13L, 13L, 13L, 13L, 5L, 5L, 5L, 5L, 6L,
    6L, 6L, 6L, 11L, 11L, 11L, 11L, 16L, 16L, 16L, 16L, 4L, 4L, 4L,
    4L, 8L, 8L, 8L, 8L, 9L, 9L, 9L, 9L, 10L, 10L, 10L, 10L, 12L,
    12L, 12L, 12L, 1L, 1L, 1L, 1L, 20L, 20L, 20L, 20L, 23L, 23L,
    23L, 23L, 25L, 25L, 25L, 25L, 26L, 26L, 26L, 26L, 21L, 21L, 21L,
    21L, 19L, 19L, 19L, 19L, 22L, 22L, 22L, 22L, 24L, 24L, 24L, 24L,
    18L, 18L, 18L, 18L, 17L, 17L, 17L, 17L, 27L, 27L, 27L, 27L), levels = 
c("M16",
    "M05", "M02", "M11", "M07", "M08", "M03", "M12", "M13", "M14",
    "M09", "M15", "M06", "M04", "M01", "M10", "F10", "F09", "F06",
    "F01", "F05", "F07", "F02", "F08", "F03", "F04", "F11"), class = 
c("ordered",
    "factor")), Sex = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
    2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
    2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
    2L, 2L, 2L, 2L), levels = c("Male", "Female"), class = "factor")), row.names = 
c("1",
    "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13",
    "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24",
    "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35",
    "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46",
    "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57",
    "58", "59", "60", "61", "62", "63", "64", "65", "66", "67", "68",
    "69", "70", "71", "72", "73", "74", "75", "76", "77", "78", "79",
    "80", "81", "82", "83", "84", "85", "86", "87", "88", "89", "90",
    "91", "92", "93", "94", "95", "96", "97", "98", "99", "100",
    "101", "102", "103", "104", "105", "106", "107", "108"), outer = ~Sex, class = 
c("nfnGroupedData",
    "nfGroupedData", "groupedData", "data.frame"), formula = distance ~
        age | Subject, labels = list(x = "Age", y = "Distance from pituitary to 
pterygomaxillary fissure"), units = list(
        x = "(yr)", y = "(mm)"), FUN = structure(function (x)
    max(x, na.rm = TRUE), source = "function (x) max(x, na.rm = TRUE)"), 
order.groups = TRUE),
        contrasts.arg = list(Sex = structure(c(0, 1), dim = 2:1, dimnames = 
list(
            c("Male", "Female"), "Female"))))
5: NextMethod(formula(object), data = data, contrasts.arg = object$contrasts)
4: model.matrix.lme(mod)
3: model.matrix(mod)
2: Anova_II_lme(mod, vcov., singular.ok = singular.ok)
1: car:::Anova.lme(fm2)
sessionInfo()
R version 4.6.1 (2026-06-24 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 10 x64 (build 19045)

Matrix products: default
   LAPACK version 3.12.1

locale:
[1] LC_COLLATE=Chinese (Simplified)_China.utf8
[2] LC_CTYPE=Chinese (Simplified)_China.utf8
[3] LC_MONETARY=Chinese (Simplified)_China.utf8
[4] LC_NUMERIC=C
[5] LC_TIME=Chinese (Simplified)_China.utf8

time zone: Asia/Shanghai
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods  base

other attached packages:
[1] car_3.1-5          carData_3.0-6      nlme_3.1-170  piecewiseSEM_2.3.1

loaded via a namespace (and not attached):
  [1] Matrix_1.7-5       jsonlite_2.0.0     compiler_4.6.1  Rcpp_1.1.2
  [5] DiagrammeR_1.0.12  splines_4.6.1      boot_1.3-32 fastmap_1.2.0
  [9] lattice_0.22-9     TH.data_1.1-5      Formula_1.2-5 MuMIn_1.48.19
[13] rbibutils_2.4.1    htmlwidgets_1.6.4  MASS_7.3-66 visNetwork_2.1.4
[17] nloptr_2.2.1       insight_1.5.2      minqa_1.2.8 RColorBrewer_1.1-3
[21] rlang_1.3.0        multcomp_1.4-31    performance_0.17.1 estimability_2.0.0
[25] cli_3.6.6          magrittr_2.0.5     Rdpack_2.6.6  emmeans_2.0.4
[29] digest_0.6.39      grid_4.6.1         mvtnorm_1.4-2 sandwich_3.1-2
[33] lme4_2.0-6         reformulas_0.4.4   glue_1.8.1  codetools_0.2-20
[37] zoo_1.8-15         survival_3.8-9     abind_1.4-8 stats4_4.6.1
[41] tools_4.6.1        htmltools_0.5.9
packageVersion("car")
[1] ‘3.1.5’
packageVersion("piecewiseSEM")
[1] ‘2.3.1’
packageVersion("nlme")
[1] ‘3.1.170’

All the packages are installed from CRAN, and updated to the latest version. I 
also run the codes on FreeBSD 15.1, the same output.

Best,

Jinsong

On 7/19/2026 2:02 PM, varin sacha wrote:
Hi,

Could this be a package compatibility bug?

Since Anova(fm2), car::Anova(fm2), and even car:::Anova.lme(fm2) all produce 
the same error, it doesn’t appear to be a simple namespace masking issue.

Could you post the output of:

traceback()
sessionInfo()
packageVersion("car")
packageVersion("piecewiseSEM")
packageVersion("nlme")

That should help identify the exact call that’s failing and whether the problem 
lies in car, piecewiseSEM, or an incompatibility between the two packages.



Le 19 juil. 2026 à 04:58, Jinsong Zhao <[email protected]> a écrit :
I have tried each solution in a new R session, and neither works.

library(piecewiseSEM)
Registered S3 method overwritten by 'lme4':
   method           from
   na.action.merMod car

   This is piecewiseSEM version 2.3.0.2.


   Questions or bugs can be addressed to <[email protected]>.
library(nlme)
library(car)
Loading required package: carData
fm2 <- lme(distance ~ age + Sex, data = Orthodont, random = ~ 1)
Anova(fm2)
Error in if (random) { : the condition has length > 1
car::Anova(fm2)
Error in if (random) { : the condition has length > 1
car:::Anova.lme(fm2)
Error in if (random) { : the condition has length > 1

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