On Wed, 07 Dec 2016 11:59:10 +0100 l...@gnu.org (Ludovic Courtès) wrote: > Eric Bavier <bav...@member.fsf.org> skribis: > > > * guix/import/json.scm (json-fetch): Use http-fetch instead of url-fetch > > to avoid writing to stdout and a temporary file for each invocation. > > * guix/import/gem.scm (rubygems-fetch): Do not redirect json-fetch > > output to /dev/null. > > * guix/import/pypi.scm (pypi-fetch): Likewise. > > [...] > > > (define (json-fetch url) > > "Return an alist representation of the JSON resource URL, or #f on > > failure." > > - (call-with-temporary-output-file > > - (lambda (temp port) > > - (and (url-fetch url temp) > > - (hash-table->alist > > - (call-with-input-file temp json->scm)))))) > > + (and=> (false-if-exception (http-fetch url)) > > + (lambda (port) > > + (let ((result (hash-table->alist (json->scm port)))) > > + (close-port port) > > + result)))) > > It’d be better to not catch exceptions raised by ‘http-fetch’ here. > Instead they’d be caught at the top level and a detailed error message > would be displayed, which is always better than silently ignoring > issues. > > However we’d need to check if there are uses where this is a problem. > For example, there might be updaters or importers that assume that #f > means that the package doesn’t exist or something like that. > > WDYT?
The importers that use json-fetch all do something like '(and=> meta ->package)', so a #f result from json-fetch is passed up to (@ (guix scripts import) guix-import) and interpreted as a "import failed". Using the false-if-exception* syntax which prints the exception message, from guix/build/download.scm might be nicer. This is the syntax that url-fetch uses. That syntax would need to be exported from somewhere. WDYT? `~Eric