When a ppx raised an exception, it was returned as an error "extension node" to
the caller, without including the "ppx context" which includes in particular ppx
cookies. This was fine when only one ppx was used, since in that case, the
missing context was not restored.
When multiple ppx are chained, however, the second ppx sees the result of the
first one, and it it does not contains a context, an empty one is created and
returned to the caller, which has the effect of destroying the context for the
next invocation of ppxs.
The current fix is to ensure that when a "error extension node" is returned, the
context is correctly added to it. In addition to fixing the reported bug, it also
allow ppx to update their cookies before raising an exception, which can be
useful.
This week we merged several changes from Thomas Refis, to allow the
use of exception patterns under or-patterns, to write code such as
match foo x with
| None | exception Not_found -> ...
| Some -> ...
Unfortunately, I failed to properly assess the impact of this change,
and in particular to make sure that Luc Maranget had properly reviewed
this code -- any change to the pattern-matching machinery should be
reviewed by Luc.
The problem that I had not foreseen and that he would have immediately
realized is that, while adapting the pattern-matching *compiler* is
relatively easy (Thomas inserted a transformation at the right place
to separate exception patterns from the others and handle them
separately, using the staticraise construct used by the
pattern-matching compiler to avoid duplicating the
right-hand-side branch), adapting the pattern-matching warnings
machinery is both more subtle and easier to overlook (it may fail
silently and nobody notices, unlike wrong code production). This part
of the compiler is subtle and best understood by Luc, but he does not
have the time to do a proper review of those changes in the timeframe
for the 4.03 feature freeze (mid-December).
I believe the right move in this case, implemented in the present
commit, is to revert the change from trunk (this is not a feature that
we must *imperatively* have in 4.03), do a proper job of understanding
the changes, and integrate the change when we are confident it is
ready. I hope to do this in 2016, together with Luc Maranget and
Thomas Refis -- hopefully this would allow Thomas and I to be more
confident when changing the pattern-matching machinery in the future.
Revert "Merge pull request #343 from trefis/pr7083"
This reverts commit 22681b8d2a, reversing
changes made to a24e4edf0a.
Revert "Merge pull request #341 from trefis/or-exception"
This reverts commit f8f68bd329, reversing
changes made to 1534fe8082.
Revert "Merge pull request #305 from trefis/or-exception"
This reverts commit cfeda89396, reversing
changes made to 77cf36cf82.
1. Revert "Switch to -custom for bytecode tests."
This reverts commit 6b7f81caf5.
2. Revert "Fix Changelog."
This reverts commit d94488d7b5.
3.Revert "Fix testsuite: use binary channels."
This reverts commit 840f7ca506.
4. Revert "Fix testsuite: do not require a globally installed ocamlrun."
This reverts commit 0388ef46d9.
5. Revert "Merge branch 'trunk' of https://github.com/bvaugon/ocaml into bvaugon-trunk"
This reverts commit 1ff6db10bf, reversing
changes made to 89d116c514.
There used to be a limitation to 32 binding groups, which is now lifted by dynamically allocating the groups data if it is too big.
Also:
- Modernize strstubs.c to use the Caml namespace
- Fixed a potential bug with backreferences \\n referring to a nonexistent group.
In a format following that of Gc.print_stat. I chose to print only the "quick_stat"
values rather than call gc_ctrl.c::heap_stats because it's lighter, and the extra
information is typically not very useful at program exit.
Also adds documentation for the 0x400 flag (in man and Gc module)
This replaces the previous undocumented 0x400 that only displayed the
total (minwords + majwords - prowords) and with a different format,
since keeping both wouldn't provide more information.
The functions now return earlier when either an element is found that
does satisfy the condition in the case of exists or an element that does
not satisfy the condition in the case of for_all.
This form used to produce Pstr_eval instead of Pstr_let. This would
probably come as a suprise for people matching on the Parsetree (e.g.
for a ppx). This special case is now removed.
To avoid a (probably harmless) regression in bytecode, the compilation
of "let _ = ..." bindings (including local ones) is optimized to remove
a useless introduction of a variable (which would occupy a stack slot
otherwise).
The source code printer (-dsource) now prints Pstr_eval as ";;expr",
which should always be ok. One could avoid ";;" at the beginning of
the structure, but since it is allowed, it is probably not worth adding
complexity here.
Damien Doligez
Thomas Refis
octachron
alainfrisch
Jeremie Dimino
Gabriel Scherer
Luc Maranget
Jacques Garrigue
Xavier Leroy
Drup
Xavier Leroy
Simon Cruanes
Rich Neswold
Bernhard Schommer
Louis Gesbert
Benoit Vaugon
Hugo Heuzard