[Bug] Incorrect version calculation for non-master mainline

[Kirill-Maurin]

For a non-"master" mainline branch a version increments twice

Expected Behavior

A version is calculated identical for any mainline branch
Test commit: Kirill-Maurin@27a2220

1. Branch "mainline": 6.0.0
2. Branch "master": 6.0.0

Actual Behavior

1. Branch "mainline": 7.0.0
2. Branch "master": 6.0.0

Possible Fix

Use !context.CurrentBranch.IsSameBranch(mainline) instead hardcode context.CurrentBranch.FriendlyName != "master"

GitVersion/src/GitVersionCore/VersionCalculation/MainlineVersionCalculator.cs

Line 72 in ba7992f

if (context.CurrentBranch.FriendlyName != "master")

Steps to Reproduce

1. Checkout test branch: https://github.com/Kirill-Maurin/GitVersion/tree/test/mainline
   GitVersion: 7.0.0
2. Reset master to commit: Kirill-Maurin@27a2220
3. Checkout master
   GitVersion: 6.0.0

[JustinGrote]

I believe I am seeing behavior related to this issue, @Kirill-Maurin can you confirm or should I open a new issue?

Steps to Reproduce

1. Have non-master mainline (production in my case)
2. Tag it as v0.8.0
3. Master is the "develop" branch for this scenario. Add a commit with +semver:minor

Expected Result

Master gitversion is 0.9.0-beta1

Actual Result

Master gitversion is 0.8.0-beta1. /diag logs say the base Increment was supposed to be 0.9.0. Changing mode to "continuousDeployment" produces the expected result for master (develop) branch, but not for production obviously anymore.

Gitversion.yml

mode: Mainline
branches:
  master:
    regex: ^prod(uction)?$
  develop:
    tag: beta
    regex: ^master$
    increment: Patch
  release:
    tag: rc

Gitversion /Diag

INFO [05/11/20 12:19:32:63] Dumping commit graph: 
INFO [05/11/20 12:19:32:83] * 03ccc17 20 seconds ago  (HEAD -> master)
* 7880e5a 7 minutes ago
* 3b46d9c 7 minutes ago
* 2198a43 8 minutes ago  (tag: v0.8.0, production)
  INFO [05/11/20 12:19:33:22] Base version used: Git tag 'v0.8.0': 0.8.0 with commit count source 2198a43bd465bd07fcbc128abd16e85f29e12e41 (Incremented: 0.9.0)
  INFO [05/11/20 12:19:33:23] End: Calculating base versions (Took: 150.40ms)
  INFO [05/11/20 12:19:33:24] Begin: Using mainline development mode to calculate current version
    INFO [05/11/20 12:19:33:25] Found possible mainline branches: production
    INFO [05/11/20 12:19:33:26] Mainline for current branch is production
    INFO [05/11/20 12:19:33:28] Current branch (master) was branch from 2198a43bd465bd07fcbc128abd16e85f29e12e41
    INFO [05/11/20 12:19:33:29] 3 commits found between 2198a43bd465bd07fcbc128abd16e85f29e12e41 and 03ccc172d53e7ed92828ef2c8618507b49636942
  INFO [05/11/20 12:19:33:31] End: Using mainline development mode to calculate current version (Took: 67.19ms)
  INFO [05/11/20 12:19:33:31] Begin: Getting version tags from branch 'refs/heads/master'.
  INFO [05/11/20 12:19:33:33] End: Getting version tags from branch 'refs/heads/master'. (Took: 19.77ms)
  INFO [05/11/20 12:19:33:34] Running on Windows.
{
  "Major":0,
  "Minor":8,
  "Patch":0,
  "PreReleaseTag":"beta.3",
  "PreReleaseTagWithDash":"-beta.3",
  "PreReleaseLabel":"beta",
  "PreReleaseNumber":3,
  "WeightedPreReleaseNumber":3,
  "BuildMetaData":"",
  "BuildMetaDataPadded":"",
  "FullBuildMetaData":"Branch.master.Sha.03ccc172d53e7ed92828ef2c8618507b49636942",
  "MajorMinorPatch":"0.8.0",
  "SemVer":"0.8.0-beta.3",
  "LegacySemVer":"0.8.0-beta3",
  "LegacySemVerPadded":"0.8.0-beta0003",
  "AssemblySemVer":"0.8.0.0",
  "AssemblySemFileVer":"0.8.0.0",
  "FullSemVer":"0.8.0-beta.3",
  "InformationalVersion":"0.8.0-beta.3+Branch.master.Sha.03ccc172d53e7ed92828ef2c8618507b49636942",
  "BranchName":"master",
  "EscapedBranchName":"master",
  "Sha":"03ccc172d53e7ed92828ef2c8618507b49636942",
  "ShortSha":"03ccc17",
  "NuGetVersionV2":"0.8.0-beta0003",
  "NuGetVersion":"0.8.0-beta0003",
  "NuGetPreReleaseTagV2":"beta0003",
  "NuGetPreReleaseTag":"beta0003",
  "VersionSourceSha":"2198a43bd465bd07fcbc128abd16e85f29e12e41",
  "CommitsSinceVersionSource":3,
  "CommitsSinceVersionSourcePadded":"0003",
  "CommitDate":"2020-05-11"
}

[asbjornu]

I see you've done some work on this, @Kirill-Maurin. Would you mind submitting a pull request with your suggested fix? Preferably with a RepositoryFixture test that provokes the problem and verifies the fix, if possible.

[Kirill-Maurin]

Would you mind submitting a pull request with your suggested fix?

Done

[Kirill-Maurin]

I believe I am seeing behavior related to this issue, @Kirill-Maurin can you confirm or should I open a new issue?

No, in your case this behavior is correct for mainline mode (IMHO)