httppeer: wrap HTTPResponse.read() globally
There were a handful of places in the code where HTTPResponse.read()
was called with no explicit error handling or with inconsistent
error handling. In order to eliminate this class of bug, we globally
swap out HTTPResponse.read() with a unified error handler.
I initially attempted to fix all call sites. However, after
going down that rabbit hole, I figured it was best to just change
read() to do what we want. This appears to be a worthwhile
change, as the tests demonstrate many of our uncaught exceptions
go away.
To better represent this class of failure, we introduce a new
error type. The main benefit over IOError is it can hold a hint.
I'm receptive to tweaking its name or inheritance.
$ hg init outer
$ cd outer
$ echo '[paths]' >> .hg/hgrc
$ echo 'default = http://example.net/' >> .hg/hgrc
hg debugsub with no remapping
$ echo 'sub = libfoo' > .hgsub
$ hg add .hgsub
$ hg debugsub
path sub
source libfoo
revision
hg debugsub with remapping
$ echo '[subpaths]' >> .hg/hgrc
$ printf 'http://example.net/lib(.*) = C:\\libs\\\\1-lib\\\n' >> .hg/hgrc
$ hg debugsub
path sub
source C:\libs\foo-lib\
revision
test cumulative remapping, the $HGRCPATH file is loaded first
$ echo '[subpaths]' >> $HGRCPATH
$ echo 'libfoo = libbar' >> $HGRCPATH
$ hg debugsub
path sub
source C:\libs\bar-lib\
revision
test absolute source path -- testing with a URL is important since
standard os.path.join wont treat that as an absolute path
$ echo 'abs = http://example.net/abs' > .hgsub
$ hg debugsub
path abs
source http://example.net/abs
revision
$ echo 'abs = /abs' > .hgsub
$ hg debugsub
path abs
source /abs
revision
test bad subpaths pattern
$ cat > .hg/hgrc <<EOF
> [subpaths]
> .* = \1
> EOF
$ hg debugsub
abort: bad subrepository pattern in $TESTTMP/outer/.hg/hgrc:2: invalid group reference (glob)
[255]
$ cd ..