Allow overriding the previous commit for a dependency

main.go

@@ -58,6 +58,7 @@ type dependency struct {
 	Sha      string
 	Previous string
 	GitURL   string
+	New      bool
 }
 
 type download struct {
@@ -75,6 +76,10 @@ type projectRename struct {
 	New string `toml:"new"`
 }
 
+type dependencyOverride struct {
+	Previous string `toml:"previous"`
+}
+
 type contributor struct {
 	Name    string
 	Email   string
@@ -100,10 +105,18 @@ type release struct {
 	//HighlightLabel string   `toml:"highlight_label"`
 	//CategoryLabels []string `toml:"category_labels"`
 
-	// dependency options
-	MatchDeps  string                   `toml:"match_deps"`
+	// MatchDeps provides a regex string to match dependencies to be
+	// included as part of the changelog.
+	MatchDeps string `toml:"match_deps"`
+	// RenameDeps provides a way to match dependencies which have been
+	// renamed from the old name to the new name.
 	RenameDeps map[string]projectRename `toml:"rename_deps"`
-	IgnoreDeps []string                 `toml:"ignore_deps"`
+	// IgnoreDeps are dependencies to ignore from the output.
+	IgnoreDeps []string `toml:"ignore_deps"`
+	// OverrideDeps is used to override the current dependency calculated
+	// from the dependency list. This can be used to set the previous version
+	// which could be missing for new or moved dependencies.
+	OverrideDeps map[string]dependencyOverride `toml:"override_deps"`
 
 	// generated fields
 	Changes      []projectChange
@@ -255,6 +268,7 @@ This tool should be ran from the root of the project repository for a new releas
 		if err != nil {
 			return err
 		}
+		overrideDependencies(current, r.OverrideDeps)
 
 		previous, err := parseDependencies(r.Previous)
 		if err != nil {

template.go

@@ -59,7 +59,7 @@ https://github.com/{{.GithubRepo}}/issues.
 ### Dependency Changes
 {{if .Dependencies}}
 {{- range $dep := .Dependencies}}
-* **{{$dep.Name}}**	{{if $dep.Previous}}{{$dep.Previous}} -> {{$dep.Ref}}{{else}}{{$dep.Ref}} **_new_**{{end}}
+* **{{$dep.Name}}**	{{if $dep.New}}{{$dep.Ref}} **_new_**{{else}}{{$dep.Previous}} -> {{$dep.Ref}}{{end}}
 {{- end}}
 {{- else}}
 This release has no dependency changes

util.go

@@ -465,6 +465,20 @@ func git(args ...string) ([]byte, error) {
 	return o, nil
 }
 
+func overrideDependencies(deps []dependency, overrides map[string]dependencyOverride) {
+	if len(overrides) == 0 {
+		return
+	}
+	for i := range deps {
+		if or, ok := overrides[deps[i].Name]; ok {
+			if or.Previous != "" {
+				logrus.Debugf("Overrode previous version of %s to %s", deps[i].Name, or.Previous)
+				deps[i].Previous = or.Previous
+			}
+		}
+	}
+}
+
 func renameDependencies(deps []dependency, renames map[string]projectRename) {
 	if len(renames) == 0 {
 		return
@@ -503,11 +517,18 @@ func getUpdatedDeps(previous, deps []dependency, ignored []string, cache Cache)
 		d, ok := pm[name]
 		if !ok {
 			// it is a new dep and should be noted
+			c.New = true
 			updated = append(updated, c)
 			continue
 		}
 		// it exists, see if its updated
-		if d.Ref != c.Ref {
+		if c.Previous != "" {
+			// Handle previous override
+			if c.Previous != c.Ref {
+				logrus.Debugf("Override dependency: %q %s -> %s", c.Name, c.Previous, c.Ref)
+				updated = append(updated, c)
+			}
+		} else if d.Ref != c.Ref {
 			if d.Sha == "" {
 				if d.GitURL == "" {
 					gitURL, err := resolveGitURL(name, cache)