Stack trace in error message does not show locations in .pm files

[+merlan #flirora]

For example, you might get the following error message:

nc: arity mismatch;
 the expected number of arguments does not match the given number
  expected: 1
  given: 2

  context...:
   body of (submod "/home/kozet/ncv9/src/grammar/nouns.html.pm" pollen-module)
   /home/kozet/.local/share/racket/8.1/pkgs/pollen/pollen/private/cache-utils.rkt:67:0: path->hash
   /home/kozet/.local/share/racket/8.1/pkgs/pollen/pollen/private/cache-utils.rkt:124:2: generate-dest-file
   /usr/share/racket/collects/file/cache.rkt:63:2: fetch-and-continue
   /usr/share/racket/collects/racket/contract/private/arrow-val-first.rkt:555:3
   /home/kozet/.local/share/racket/8.1/pkgs/pollen/pollen/private/cache-utils.rkt:114:0: cache-ref!
   /usr/share/racket/collects/racket/private/more-scheme.rkt:377:2: hash-ref!
   /home/kozet/.local/share/racket/8.1/pkgs/pollen/pollen/cache.rkt:39:4: cached-require-base
   body of 'g43165
   /home/kozet/.local/share/racket/8.1/pkgs/pollen/pollen/render.rkt:386:0: render-markup-or-markdown-source
   /home/kozet/.local/share/racket/8.1/pkgs/pollen/pollen/render.rkt:312:25: render
   /home/kozet/.local/share/racket/8.1/pkgs/pollen/pollen/private/cache-utils.rkt:124:2: generate-dest-file
   /usr/share/racket/collects/file/cache.rkt:63:2: fetch-and-continue
   /usr/share/racket/collects/racket/contract/private/arrow-val-first.rkt:555:3
   /home/kozet/.local/share/racket/8.1/pkgs/pollen/pollen/private/cache-utils.rkt:114:0: cache-ref!
   /usr/share/racket/collects/racket/private/more-scheme.rkt:377:2: hash-ref!
   ...
pollen: /error.css 

where you don't get any information on where in nouns.html.pm the error is.

[Matthew Butterick]

AFAIK that’s just the way errors are reported when they arise from modules that are synthesized at compile time. For instance, this source:

#lang scribble/manual

@(error 'boom)

Produces this error:

error: boom
  context...:
   body of "path/to/foo.scrbl"

[sorawee]

FWIW, errortrace can work with Pollen programs. Given:

#lang pollen

Hello ◊(/ 1 0) world

Running racket test.html.pm results in:

/: division by zero
  context...:
   body of (submod "/Users/sorawee/test.html.pm" pollen-module)

But running racket -l errortrace -t test.html.pm results in:

/: division by zero
  errortrace...:
   /Users/sorawee/test.html.pm:3:7: (/ 1 0)
  context...:
   body of (submod "/Users/sorawee/test.html.pm" pollen-module)