wiki/debug.warning.md

In ProvTools/provDebugR: A Time-Travelling Debugger

debug.warning returns a data frame representing the backwards lineage of (the steps leading up to) each warning queried.

Each data frame contains the following columns: scriptNum The script number the exception is associated with. scriptName The name of the script the exception is associated with. startLine The line number the exception is associated with. code The line of code which threw the exception.

Usage

The function signature for debug.warning is:

debug.warning(..., all = FALSE)

The parameters for this function are: ... The index of the warning(s) to be queried. As all warning nodes have the same name, their index (order of occurrence) is used to distinguish them. all If TRUE, the backwards lineages of all warnings are returned.

This function may be called only after initialising the debugger using either prov.debug, prov.debug.run, or prov.debug.file. For example:

prov.debug.run("myScript.R")
debug.warning(1)
debug.warning(2,3)
debug.warning(all = TRUE)

Output Examples

Let myScript.R be the following:

warning("This is a test")

x <- 1
y <- 2
z <- 3
cor(c(x, x), c(y, z))

Running this script will result in 2 warnings, the first from line 1, and the second from line 6:

Warning messages:
1: In eval(annot, environ, NULL) : This is a test
2: In cor(c(x, x), c(y, z)) : the standard deviation is zero

1. Obtaining the lineage for a warning

Calling debug.warning(2) will give the backwards lineage of the second warning:

$`2`
  scriptNum scriptName startLine                  code
1         1 myScript.R        3                x <- 1
2         1 myScript.R         4                y <- 2
3         1 myScript.R         5                z <- 3
4         1 myScript.R         6 cor(c(x, x), c(y, z))

2. Obtaining the lineage for multiple warnings

Multiple warnings may be queried at once to get the lineages of multiple warnings.

For example, the result for debug.warning(1,2) is:

$`1`
  scriptNum scriptName startLine                      code
1         1 myScript.R         1 warning("This is a test")

$`2`
  scriptNum scriptName startLine                  code
1         1 myScript.R         3                x <- 1
2         1 myScript.R         4                y <- 2
3         1 myScript.R         5                z <- 3
4         1 myScript.R         6 cor(c(x, x), c(y, z))

3. No parameters

If no parameters are passed to debug.warning, a table of all warnings, if any, will be displayed.

For example, calling debug.warning() will result in:

Possible options:

1            In  eval(annot, environ, NULL) :  This is a test
2 In  cor(c(x, x), c(y, z)) :  the standard deviation is zero

Pass the corresponding numeric value to the function for info on that warning.

ProvTools/provDebugR documentation built on April 29, 2021, 7:22 p.m.