hgweb: log error before attempting I/O
Previously, an uncaught exception during HTTP request serving would
attempt to send an error response then log the exception.
If an exception occurred during I/O, this exception would be
raised and the original exception wouldn't be logged.
This commit changes behavior so the original exception is logged
first, before we attempt to do anything else. This ensures the
exception is logged.
This change resulted in new tracebacks appearing in various tests.
Because tracebacks can vary between Python versions, we added a
simple script to filter the stack part of traceback lines. This
makes testing much simpler, as we don't need to glob over lines
and make lines conditional.
Differential Revision: https://phab.mercurial-scm.org/D5749
Setup:
$ cat > eval.py <<EOF
> from __future__ import absolute_import
> import filecmp
> from mercurial import commands, context, pycompat, registrar
> cmdtable = {}
> command = registrar.command(cmdtable)
> @command(b'eval', [], b'hg eval CMD')
> def eval_(ui, repo, *cmds, **opts):
> cmd = b" ".join(cmds)
> res = pycompat.bytestr(eval(cmd, globals(), locals()))
> ui.warn(b"%s" % res)
> EOF
$ echo "[extensions]" >> $HGRCPATH
$ echo "eval=`pwd`/eval.py" >> $HGRCPATH
Arbitraryfilectx.cmp does not follow symlinks:
$ mkdir case1
$ cd case1
$ hg init
#if symlink
$ printf "A" > real_A
$ printf "foo" > A
$ printf "foo" > B
$ ln -s A sym_A
$ hg add .
adding A
adding B
adding real_A
adding sym_A
$ hg commit -m "base"
#else
$ hg import -q --bypass - <<EOF
> # HG changeset patch
> # User test
> # Date 0 0
> base
>
> diff --git a/A b/A
> new file mode 100644
> --- /dev/null
> +++ b/A
> @@ -0,0 +1,1 @@
> +foo
> \ No newline at end of file
> diff --git a/B b/B
> new file mode 100644
> --- /dev/null
> +++ b/B
> @@ -0,0 +1,1 @@
> +foo
> \ No newline at end of file
> diff --git a/real_A b/real_A
> new file mode 100644
> --- /dev/null
> +++ b/real_A
> @@ -0,0 +1,1 @@
> +A
> \ No newline at end of file
> diff --git a/sym_A b/sym_A
> new file mode 120000
> --- /dev/null
> +++ b/sym_A
> @@ -0,0 +1,1 @@
> +A
> \ No newline at end of file
> EOF
$ hg up -q
#endif
These files are different and should return True (different):
(Note that filecmp.cmp's return semantics are inverted from ours, so we invert
for simplicity):
$ hg eval "context.arbitraryfilectx(b'A', repo).cmp(repo[None][b'real_A'])"
True (no-eol)
$ hg eval "not filecmp.cmp(b'A', b'real_A')"
True (no-eol)
These files are identical and should return False (same):
$ hg eval "context.arbitraryfilectx(b'A', repo).cmp(repo[None][b'A'])"
False (no-eol)
$ hg eval "context.arbitraryfilectx(b'A', repo).cmp(repo[None][b'B'])"
False (no-eol)
$ hg eval "not filecmp.cmp(b'A', b'B')"
False (no-eol)
This comparison should also return False, since A and sym_A are substantially
the same in the eyes of ``filectx.cmp``, which looks at data only.
$ hg eval "context.arbitraryfilectx(b'real_A', repo).cmp(repo[None][b'sym_A'])"
False (no-eol)
A naive use of filecmp on those two would wrongly return True, since it follows
the symlink to "A", which has different contents.
#if symlink
$ hg eval "not filecmp.cmp(b'real_A', b'sym_A')"
True (no-eol)
#else
$ hg eval "not filecmp.cmp(b'real_A', b'sym_A')"
False (no-eol)
#endif