feat: Add vcsBaseCommitSha to estimate metadata

It's empty on breakdown, and base branch's HEAD SHA on diff/output.
NB: When combining several JSONs in output command latest item's
metadata will be used in the output.

cmd/infracost/run.go

@@ -92,6 +92,7 @@ func runMain(cmd *cobra.Command, runCtx *config.RunContext) error {
  logging.Logger.Debug().Err(err).Msgf("failed to fetch vcs metadata for path %s", repoPath)
  }
  runCtx.VCSMetadata = metadata
+ runCtx.VCSMetadata.BaseCommit = vcs.Commit{}
 
  pr, err := newParallelRunner(cmd, runCtx)
  if err != nil {
@@ -123,6 +124,13 @@ func runMain(cmd *cobra.Command, runCtx *config.RunContext) error {
  if err != nil {
  return err
  }
+ runCtx.VCSMetadata.BaseCommit = vcs.Commit{
+ SHA: pr.prior.Metadata.CommitSHA,
+ AuthorName: pr.prior.Metadata.CommitAuthorName,
+ AuthorEmail: pr.prior.Metadata.CommitAuthorEmail,
+ Time: pr.prior.Metadata.CommitTimestamp,
+ Message: pr.prior.Metadata.CommitMessage,
+ }
  }
 
  r.IsCIRun = runCtx.IsCIRun()

internal/output/metadata.go

@@ -11,6 +11,7 @@ type Metadata struct {
  InfracostCommand string `json:"infracostCommand"`
 
  Branch string `json:"vcsBranch"`
+ BaseCommitSHA string `json:"vcsBaseCommitSha,omitempty"`
  CommitSHA string `json:"vcsCommitSha"`
  CommitAuthorName string `json:"vcsCommitAuthorName"`
  CommitAuthorEmail string `json:"vcsCommitAuthorEmail"`
@@ -38,6 +39,7 @@ func NewMetadata(ctx *config.RunContext) Metadata {
  m := Metadata{
  InfracostCommand: ctx.CMD,
  Branch: ctx.VCSMetadata.Branch.Name,
+ BaseCommitSHA: ctx.VCSMetadata.BaseCommit.SHA,
  CommitSHA: ctx.VCSMetadata.Commit.SHA,
  CommitAuthorEmail: ctx.VCSMetadata.Commit.AuthorEmail,
  CommitAuthorName: ctx.VCSMetadata.Commit.AuthorName,

internal/vcs/metadata.go

@@ -1056,6 +1056,7 @@ type Metadata struct {
  Remote Remote
  Branch Branch
  Commit Commit
+ BaseCommit Commit
  PullRequest *PullRequest
  Pipeline *Pipeline
 }

schema/infracost.schema.json

@@ -120,6 +120,9 @@
  "vcsBranch": {
  "type": "string"
  },
+ "vcsBaseCommitSha": {
+ "type": "string"
+ },
  "vcsCommitSha": {
  "type": "string"
  },