From: merch-redmine@... Date: 2016-11-26T04:19:23+00:00 Subject: [ruby-core:78368] [Ruby trunk Feature#12882] Add caller/file/line information to internal Kernel#warn calls Issue #12882 has been updated by Jeremy Evans. matz, did you want to modify the Kernel#warn API? Currently, I don't think modifying the Kernel#warn API can be done in a backwards compatible way, as Kernel#warn accepts an arbitrary number of arguments and converts them all to strings. We could support this with keyword arguments, using an API like `warn("message", caller: 1)`, but it wouldn't be completely backward compatible as that currently prints the `message` and `{:caller=>1}` to stderr. If such a change is acceptable, I can work on implementing this. Since Kernel#warn would add an extra call frame, we would have to add 1 to the :caller option. Did you want to modify Kernel#warn's behavior to automatically assume `caller: 1` if no `:caller` keyword argument is given? Most of the stdlib calls to Kernel#warn use `caller(1,1)` before calling Kernel#warn. This would be a bigger break to backwards compatibility, as external callers to Kernel#warn (outside the stdlib) that included caller information would result in the caller information appearing twice in the error output. If you want something completely backwards compatible, we either need to continue to include the caller information manually in error messages passed to Kernel#warn (as this patch does), or we need to add a new method (which seems undesireable to me). Assuming you want to keep backwards compatibility and include caller information manually in calls to Kernel#warn, what are your thoughts on adding Thread::Backtrace::Location#file_and_line (or similar method) and then using `caller_locations(1,1).first.file_and_line` in most of the warning messages? ---------------------------------------- Feature #12882: Add caller/file/line information to internal Kernel#warn calls https://bugs.ruby-lang.org/issues/12882#change-61738 * Author: Jeremy Evans * Status: Open * Priority: Normal * Assignee: ---------------------------------------- Most internal uses of Kernel#warn do not begin with caller/file/line information, making debugging such warnings more difficult, and hindering filtering/processing of warnings on a per-file/directory/gem basis when overriding Warning.warn (a new feature in ruby 2.4). I think it would be better if internal calls to Kernel#warn in ruby code included caller information, so the warnings generated are similar to those generated by rb_warn in C code. I'm attaching an initial attempt at this. There was a lot of internal inconsistency in existing warning messages that include caller information. I choose to standardize on `caller(1,1).first`. Specifying 1 as the length argument to caller provides a 5-10x speedup compared to the default of nil as the length argument, and since warning messages only use the first line, there's no need to generate additional lines. I also benchmarked using caller_locations, but that didn't seem to perform better, probably because the result is just converted to a string anyway. Some existing warning messages that include caller information use #caller but attempt to strip out the method information via gsub. I'm guessing it would be better to use #caller_locations. However, that's kind of cumbersome right now, if we want to do that, we should probably add a method to Thread::Backtrace::Location that returns just the absolute_path and lineno as a string, so we could standardize on `caller_locations(1,1).first.file_and_line` (or whatever the method is called). There are a few questionable changes in the attached patch, such as the use of `caller(0,1)` in certain cases (when the changes were at top level), or including caller information in warning messages that were only output in DEBUG mode. The attached patch does not include changes for rdoc and rubygems, as those are maintained in separate repositories. Assuming that this patch or a similar one is accepted, I can submit patches to both rdoc and rubygems for their warning messages. ---Files-------------------------------- 0001-Prepend-warning-messages-with-caller-information.patch (30.6 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: