8299829: In jshell, the output of "0".repeat(49999)+"2" ends with a '0'

[asotona]

"0".repeat(49999)+"2" correctly evaluates to a string with a terminating '2'.
However, jshell outputs it with a terminating '0'.

Jshell provides double truncation of long Strings.
One is performed in jdk.jshell.execution.ExecutionControlForwarder to fit into MAX_UTF_CHARS = 21844 (which is exactly the point where "2" disappears).
Second truncation is performed in jdk.internal.jshell.tool.Feedback to fit presentation requirements.
While ExecutionControlForwarder truncates right part of the String, Feedback truncated inner part in 2/3 and joins the parts with " ... ".

Proposed patch fixes ExecutionControlForwarder to truncate long Strings the same way as Feedback, so the right part of any long String won't disappear and double or repeated truncation provides consistent results.

Please review :)

Thanks,
Adam

---

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Issue

• JDK-8299829: In jshell, the output of "0".repeat(49999)+"2" ends with a '0'

Reviewers

• Jan Lahoda (@lahodaj - Reviewer)

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[mlbridge]

Webrevs

• 01: Full - Incremental (6f014b6c)
• 00: Full (d6ff2bf2)

[lahodaj]

Looks good to me. Thanks!

[openjdk]

@asotona This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8299829: In jshell, the output of "0".repeat(49999)+"2" ends with a '0'

Reviewed-by: jlahoda

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At the time when this comment was updated there had been 2 new commits pushed to the master branch:

• 5a51ef2: 8297874: get_dump_directory() in jfrEmergencyDump.cpp should pass correct length to jio_snprintf
• a86b6f6: 8299183: Invokers.checkExactType passes parameters to create WMTE in opposite order

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[asotona]

/integrate

[openjdk]

Going to push as commit 030e88d.
Since your change was applied there have been 9 commits pushed to the master branch:

• ef32fdb: 8284825: sun/java2d/DirectX/MultiPaintEventTest/MultiPaintEventTest.java failed with "RuntimeException: Processed unnecessary paint()."
• 95b102c: 8299309: Test "java/awt/Dialog/ModalDialogTest/ModalDialogTest.java" fails because new frame was not displayed when "New Frame" button was clicked
• f312c99: 8299482: Remove metaprogramming/isIntegral.hpp
• 10a747c: 8299479: Remove metaprogramming/decay.hpp
• ddca2b9: 8299701: Remove unused GCCause::_wb_conc_mark
• c595f96: 8299278: tools/jpackage/share/AddLauncherTest.java#id1 failed AddLauncherTest.bug8230933
• 3c99e78: 8298735: Some tools/jpackage/windows/* tests fails with jtreg test timeout
• 5a51ef2: 8297874: get_dump_directory() in jfrEmergencyDump.cpp should pass correct length to jio_snprintf
• a86b6f6: 8299183: Invokers.checkExactType passes parameters to create WMTE in opposite order

Your commit was automatically rebased without conflicts.

[openjdk]

@asotona Pushed as commit 030e88d.

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