Bug #8279: Single-line rescue parsing

• Status: Closed
• Assignee: matz (Yukihiro Matsumoto)
• Target version: -
• ruby -v: 2.0.0p0

[dunric (David Unric)]

Hi,

there seems to be a bug in parser for single-line rescue statement. It fails in case of multiple assignment statements, keeping operator precedence vs. simple assignment etc.

obj = expression rescue objval

parsed as

obj = (expression rescue objval)

obj1, obj2 = expression rescue [objval1, objval2]

parsed as

(obj1, obj2 = expression) rescue [objval1, objval2]

obj += expression rescue objval

parsed as

obj += (expression rescue objval)

obj = obj + expression rescue objval

parsed as

obj = (obj + expression) rescue objval

There is already a thread about this issue on ruby-forum.com, even Matz himself is aware and did gave a nod to this problem http://www.ruby-forum.com/topic/152260#671711 , though nothing was done to fix it yet.

I've tried to report about this problem once (http://bugs.ruby-lang.org/issues/8239) but it was ignored for no known reason.

[nobu (Nobuyoshi Nakada)]

• Priority changed from 5 to Normal

[jeremyevans0 (Jeremy Evans)]

• File massign-rescue-modifier-8279.patch massign-rescue-modifier-8279.patch added

This bug is still present in the master branch. Attached is a patch that fixes it, so that multiple assignment with rescue modifier is consistent with single assignment with rescue modifier. After the patch:

a = raise rescue 1 # a = (raise rescue 1)
a, b = raise rescue [1, 2] # a, b = (raise rescue [1, 2])

[nobu (Nobuyoshi Nakada)]

Thank you, it seems fine. I've missed this at all.

• Status changed from Open to Closed

Applied in changeset git|53b3be5d58a9bf1efce229b3dce723f96e820c79.

---

Fix parsing of mutiple assignment with rescue modifier

Single assignment with rescue modifier applies rescue to the RHS:

a = raise rescue 1 # a = (raise rescue 1)

Previously, multiple assignment with rescue modifier applied rescue
to the entire expression:

a, b = raise rescue [1, 2] # (a, b = raise) rescue [1, 2]

This makes multiple assignment with rescue modifier consistent with
single assignment with rescue modifier, applying rescue to the RHS:

a, b = raise rescue [1, 2] # a, b = (raise rescue [1, 2])

Implements [Feature #8239]
Fixes [Bug #8279]

[mame (Yusuke Endoh)]

• Related to Bug #20790: Syntax acceptance of `*x = p rescue p 1` is different between parse.y and prism added