Read previousVersions for bincompat checking from a file

[jackkoenig]

This makes it much easier to automate checking new versions as they are released.

Contributor Checklist

• Did you add Scaladoc to every public function/method?
• Did you add at least one test demonstrating the PR?
• Did you delete any extraneous printlns/debugging code?
• Did you specify the type of improvement?
• Did you add appropriate documentation in docs/src?
• Did you request a desired merge strategy?
• Did you add text to be included in the Release Notes for this change?

Type of Improvement

• Internal or build-related (includes code refactoring/cleanup)

Desired Merge Strategy

• Squash

Release Notes

We can now simply append versions as they are released to project/previous-versions.txt on relevant release branches. build.sbt also now contains instructions are how to waive binary compatibility breakages.

Reviewer Checklist (only modified by reviewer)

• Did you add the appropriate labels? (Select the most appropriate one based on the "Type of Improvement")
• Did you mark the proper milestone (Bug fix: 3.5.x or 3.6.x depending on impact, API modification or big change: 5.0.0)?
• Did you review?
• Did you check whether all relevant Contributor checkboxes have been checked?
• Did you do one of the following when ready to merge:
  • Squash: You/ the contributor Enable auto-merge (squash), clean up the commit message, and label with Please Merge.
  • Merge: Ensure that contributor has cleaned up their commit history, then merge with Create a merge commit.

[jackkoenig]

Hard to test this sort of automation in CI, but I did test it locally and was able to get failures by running:

Show no issues

$ sbt "unipublish / mimaReportBinaryIssues"                             
[info] welcome to sbt 1.8.2 (GraalVM Community Java 11.0.13)                                             
[info] loading settings for project chisel5-build from plugins.sbt ...                                   
[info] loading project definition from /Users/jackk/work/chisel5/project                                 
[info] loading settings for project chisel from build.sbt ...                                            
[info] resolving key references (12864 settings) ...                                                     
[info] set current project to chisel (in build file:/Users/jackk/work/chisel5/)                          
[info] chisel-plugin: mimaPreviousArtifacts is empty, not analyzing binary compatibility.                
[info] compiling 1 Scala source to /Users/jackk/work/chisel5/firrtl/target/scala-2.13/classes ...        
[info] compiling 1 Scala source to /Users/jackk/work/chisel5/core/target/scala-2.13/classes ...          
[info] compiling 82 Scala sources to /Users/jackk/work/chisel5/target/scala-2.13/classes ...             
[info] chisel: mimaPreviousArtifacts is empty, not analyzing binary compatibility.                       
[success] Total time: 19 s, completed Apr 24, 2023, 4:57:28 PM

Add a previous version

$ echo "5.0.0-RC1" >> project/previous-versions.txt

Show failures

$ sbt "unipublish / mimaReportBinaryIssues"                             
[info] welcome to sbt 1.8.2 (GraalVM Community Java 11.0.13)                                             
[info] loading settings for project chisel5-build from plugins.sbt ...                                   
[info] loading project definition from /Users/jackk/work/chisel5/project                                 
[info] loading settings for project chisel from build.sbt ...                                            
[info] resolving key references (12864 settings) ...                                                     
[info] set current project to chisel (in build file:/Users/jackk/work/chisel5/)                          
[error] chisel: Failed binary compatibility check against org.chipsalliance:chisel_2.13:5.0.0-RC1! Found 7 potential problems
[error]  * method this(chisel3.Data,scala.math.BigInt)Unit in class chisel3.Mem does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("chisel3.Mem.this")           
[error]  * method this(chisel3.Data,scala.math.BigInt)Unit in class chisel3.MemBase does not have a correspondent in current version                 
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("chisel3.MemBase.this")       
[error]  * method this(chisel3.Data,scala.math.BigInt,scala.Enumeration#Value)Unit in class chisel3.SyncReadMem does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("chisel3.SyncReadMem.this")   
[error]  * class chisel3.internal.firrtl.PartialConnect does not have a correspondent in current version 
[error]    filter with: ProblemFilters.exclude[MissingClassProblem]("chisel3.internal.firrtl.PartialConnect")                                        
[error]  * object chisel3.internal.firrtl.PartialConnect does not have a correspondent in current version                                             
[error]    filter with: ProblemFilters.exclude[MissingClassProblem]("chisel3.internal.firrtl.PartialConnect$")                                       
[error]  * class firrtl.ir.PartialConnect does not have a correspondent in current version               
[error]    filter with: ProblemFilters.exclude[MissingClassProblem]("firrtl.ir.PartialConnect")          
[error]  * object firrtl.ir.PartialConnect does not have a correspondent in current version              
[error]    filter with: ProblemFilters.exclude[MissingClassProblem]("firrtl.ir.PartialConnect$")         
[error] java.lang.RuntimeException: Failed binary compatibility check against org.chipsalliance:chisel_2.13:5.0.0-RC1! Found 7 potential problems

Waive failures

cat << EOF > unipublish/src/main/mima-filters/5.0.0-RC1.backwards.excludes
ProblemFilters.exclude[DirectMissingMethodProblem]("chisel3.Mem.this")
ProblemFilters.exclude[DirectMissingMethodProblem]("chisel3.MemBase.this")
ProblemFilters.exclude[DirectMissingMethodProblem]("chisel3.SyncReadMem.this")
ProblemFilters.exclude[MissingClassProblem]("chisel3.internal.firrtl.PartialConnect")
ProblemFilters.exclude[MissingClassProblem]("chisel3.internal.firrtl.PartialConnect$")
ProblemFilters.exclude[MissingClassProblem]("firrtl.ir.PartialConnect")
ProblemFilters.exclude[MissingClassProblem]("firrtl.ir.PartialConnect$")
EOF

Show success

$ sbt "unipublish / mimaReportBinaryIssues"
[info] welcome to sbt 1.8.2 (GraalVM Community Java 11.0.13)
[info] loading settings for project chisel5-build from plugins.sbt ...
[info] loading project definition from /Users/jackk/work/chisel5/project
[info] loading settings for project chisel from build.sbt ...
[info] resolving key references (12864 settings) ...
[info] set current project to chisel (in build file:/Users/jackk/work/chisel5/)
[success] Total time: 3 s, completed Apr 24, 2023, 5:04:35 PM