REPL does not read version from fregec.jar?

I just downloaded Frege REPL 1.2.1-SNAPSHOT, and changed the fregei shell script so that it uses frege3.22.525-g704b834.jar.

However, the version displayed is still 424:

ingo@freguntu:/tmp$ frepl  # just alias to fregei
/home/ingo/bin/java
Welcome to Frege 3.22.524-gcc99d7e (Oracle Corporation Java HotSpot(TM) 64-Bit Server VM, 1.8.0_40)

frege> :version
3.22.524-gcc99d7e

frege> 10-2*3
4

But because it outputs the correct result from the expression (instead 24) means that it actually uses the 525 jar.

I think it would be better to report the actual version from frege.Version. For, when we get a bug report, it'll be hard to establish which frege jar is actually used otherwise.

REPL does read version from frege.Version.version but the problem seems to be that since it is a constant on the Version module, Java compiler is basically inlining the constant value in FregeRepl module. Thus it ends up as a constant in the class file and it doesn't use Version.version at runtime.

This is clear from the bytecode of FregeRepl module:

javap -cp "./lib/*" -verbose frege.repl.FregeRepl | less

And the relevant bit of bytecode:

169: ldc_w         #323                // String Welcome to Frege
172: ldc           #204                // String 3.22.524-gcc99d7e

The StackOverflow threads, this and this, touch upon this problem and the solution seems to be adding an intern() call on the version string so that the compiler doesn't inline the constant.

@Ingo60

@Ingo60 do we have to do anything for this issue?

Navigation Menu

Repository navigation

REPL does not read version from fregec.jar? #33

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

REPL does not read version from fregec.jar? #33

Description

Activity

mmhelloworld commented on Aug 27, 2015

mmhelloworld commented on May 24, 2016

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions