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<p class="MsoNormal">Hi,</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I'm enclosing a changeset that entirely removes unwind code duplicity in Context AND at the same time fixes the "stepOver bug" still persisting in the system.</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">To refresh what the bug is: You cannot #stepOver '^2' when you debug;</p>
<p class="MsoNormal">[^2] ensure: [] "step through to ^2 and try step over --> you get BCR"</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The root cause is #return:from: supplies 'firstUnwindContext' to #aboutToReturn:through: but before this gets evaluated the real first unwind context changes during simulation and that causes the bug.</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Originally (prior 2012), #aboutToReturn:through: just called 'self methodReturnContext return: result' and didn't use the 'firstUnwindContext' but in 2012 the call has been replaced with 'self methodReturnContext return: result through:
firstUnwindContext' and the bug was born.</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In the changeset I suggest to use one common method replacing #resume:through: and #resumeEvaluating: which solves the bug as a side-effect with only a tiny change in #return:from: (simply supply nil instead of 'firstUnwindContext').</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I will post the changeset to the Inbox soon.</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best,</p>
<p class="MsoNormal">Jaromir</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNoSpacing"><span lang="CS">--</span></p>
<p class="MsoNoSpacing"><strong><span style="font-family:"Calibri Light",sans-serif;color:#333333;font-weight:normal">Jaromír Matas</span></strong><span style="font-family:"Calibri Light",sans-serif;color:#555555"><o:p></o:p></span></p>
<p class="MsoNoSpacing"><span style="font-family:"Calibri Light",sans-serif;color:#2E75B6">mail@jaromir.net<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#8FAADC"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="border:none;padding:0in"><b>From: </b><a href="mailto:mail@jaromir.net">Jaromir Matas</a><br>
<b>Sent: </b>Thursday, February 2, 2023 15:07<br>
<b>To: </b><a href="mailto:squeak-dev@lists.squeakfoundation.org">Squeak Dev</a><br>
<b>Subject: </b>[squeak-dev] Code duplication around unwinding</p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">When I started learning Squeak I wondered why so much code duplication around unwinding: Context>>#restart, #resume:through:, #resumeEvaluating:, #terminate and #unwindTo: all implementing the exact same algorithm. Kernel-jar.1499 suggests
removing all this duplicity while keeping the current unwind semantics. All Process and Exceptions tests are green.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This changeset is the first step in my effort to reduce the "noise" around the "collection" of resume/return methods in Context and Exception. One idea is to return calling the unwind mechanism back to the Exception class, as originally
implemented in Squeak 2.x up to 3.5; please let me know if you find something fundamentally wrong with this idea.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Example: I find this call sequence begging for simplification:
<o:p></o:p></p>
<p class="MsoNormal">Exception>>resume: --> resumeUnchecked: --> resumeEvaluating: --> Context>>returnEvaluating: --> resumeEvaluating:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Jaromir<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNoSpacing"><span lang="CS">--</span></p>
<p class="MsoNoSpacing"><strong><span style="font-family:"Calibri Light",sans-serif;color:#333333;font-weight:normal">Jaromír Matas</span></strong><span style="font-family:"Calibri Light",sans-serif;color:#555555"><o:p></o:p></span></p>
<p class="MsoNoSpacing"><span style="font-family:"Calibri Light",sans-serif;color:#2E75B6">mail@jaromir.net<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#8FAADC"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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