commands: cross-platform log formatting to files#2178
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Looks good. Great description of the fix :)
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In PR git-lfs#1466 we introduced our custom "errors" package as a replacement for the "errutil" package used previously to provide various error handling functions and specialized error types. As part of this PR, in commit 8624a87 we defined the StackTrace() function in the new "errors" package, and updated the logPanicToWriter() function in our "commands" package to call it when generating an error log file. We write these log files to the .git/lfs/logs directory whenever a Git LFS command invokes one of our error reporting utility functions such as LoggedError() or Panic(). Later, in commit 377366d of PR git-lfs#2178, we revised the logPanicToWriter() function to use the "%+v" format string specifier when writing an error's details to the log file, and dropped the call to the StackTrace() function of our "errors" package. The StackTrace() call was deemed no longer necessary because we expect all of our errors to be created using our "errors" package's functions, which instantiate error structures defined by the legacy "github.com/pkg/errors" package. This package defines its own Format() methods for its structures so that when the "%+v" format string specifier is used with them, they output both the message and stack trace associated with each error. As a consequence of this change in PR git-lfs#2178, the StackTrace() function in our own custom "errors" package has no remaining callers, so we can remove it now.
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In PR git-lfs#1466 we introduced our custom "errors" package as a replacement for the "errutil" package used previously to provide various error handling functions and specialized error types. As part of this PR, in commit 8624a87 we defined the StackTrace() function in the new "errors" package, and updated the logPanicToWriter() function in our "commands" package to call it when generating an error log file. We write these log files to the .git/lfs/logs directory whenever a Git LFS command invokes one of our error reporting utility functions such as LoggedError() or Panic(). Later, in commit 377366d of PR git-lfs#2178, we revised the logPanicToWriter() function to use the "%+v" format string specifier when writing an error's details to the log file, and dropped the call to the StackTrace() function of our "errors" package. The StackTrace() call was deemed no longer necessary because we expect all of our errors to be created using our "errors" package's functions, which instantiate error structures defined by the legacy "github.com/pkg/errors" package. This package defines its own Format() methods for its structures so that when the "%+v" format string specifier is used with them, they output both the message and stack trace associated with each error. As a consequence of this change in PR git-lfs#2178, the StackTrace() function in our own custom "errors" package has no remaining callers, so we can remove it now.
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This pull request addresses the second and third points of #2076:
This one required some investigation. I originally thought that the goal here was to replace all instances of printing LF (
\n) characters sent to the terminal, but the actual fix is to just print platform-specific line ending sequences to files on disk, not the terminal.To determine this, I wrote two files to my
~/github/sharedirectory, which is accessible via my Windows VM. Each had the words "foo" and "bar". One was separated by a LF character, and the other by a CRLF, as follows:On Windows, they render in the terminal as expected independent of the line ending sequences (tested via cmd.exe, and reproducible in Git Bash):
So the fix in 43ec8e9 involved:
lineEndingargument to thelogPanicToWriter()func. This function is used to print to bothos.Stderr, as well as*os.Fileinstances, so it needs to be able to handle eitherLForCRLFs.gitLineEndingfunc, which prefers yourcore.autocrlfsetting, or defaults to the platform correct sequence instead.This is a larger problem with my (perhaps) excessive use of error-wrapping, but is easily solved by formatting errors with
%+vinstead of%s. Here's a before and after:%s(old):%+v(new):Closes: #2076.
/cc @git-lfs/core @JarrettR #2076