dependabot,renovate: handle revert commits

src/app/generate/generate_test.go

@@ -34,7 +34,7 @@ This is a release note
 - This is in the past and should not be included
 `
 
-//nolint:funlen,paralleltest
+//nolint:funlen,maintidx,paralleltest
 func TestGenerate(t *testing.T) {
 	for _, tc := range []struct {
 		name           string
@@ -120,6 +120,72 @@ dependencies:
         commit: chore(deps): bump anotherdep from 0.0.1 to 0.0.2 (#69)
 			`) + "\n",
 		},
+		{
+			name: "Markdown_Reverted_Dependency",
+			md: strings.TrimSpace(`
+# Changelog
+This is based on blah blah blah
+
+## Unreleased
+
+## v1.2.3 - 20YY-DD-MM
+
+### Enhancements
+- This is in the past and should not be included
+			`) + "\n",
+			args:   "",
+			author: "not a bot <not-a@bot.com>",
+			commits: []string{
+				"Revert \"chore(deps): bump thisdep from 1.7.0 to 1.10.1\"",
+			},
+			expected: strings.TrimSpace(`
+notes: ""
+changes: []
+dependencies:
+    - name: thisdep
+      from: 1.10.1
+      to: 1.7.0
+      meta:
+        commit: Revert "chore(deps): bump thisdep from 1.7.0 to 1.10.1"
+			`) + "\n",
+		},
+		{
+			// This test case does not represent the behavior we would like, but servers as an acknowledgement
+			// of the limitations of the current behavior.
+			name: "Markdown_Dependency_And_Revert",
+			md: strings.TrimSpace(`
+# Changelog
+This is based on blah blah blah
+
+## Unreleased
+
+## v1.2.3 - 20YY-DD-MM
+
+### Enhancements
+- This is in the past and should not be included
+			`) + "\n",
+			args:   "",
+			author: "dependabot <dependabot@github.com>",
+			commits: []string{
+				"chore(deps): bump thisdep from 1.7.0 to 1.10.1",
+				"Revert \"chore(deps): bump thisdep from 1.7.0 to 1.10.1\"",
+			},
+			expected: strings.TrimSpace(`
+notes: ""
+changes: []
+dependencies:
+    - name: thisdep
+      from: 1.7.0
+      to: 1.10.1
+      meta:
+        commit: chore(deps): bump thisdep from 1.7.0 to 1.10.1
+    - name: thisdep
+      from: 1.10.1
+      to: 1.7.0
+      meta:
+        commit: Revert "chore(deps): bump thisdep from 1.7.0 to 1.10.1"
+			`) + "\n",
+		},
 		{
 			name:   "Markdown_Dependabot",
 			md:     mdChangelog,

src/changelog/sources/dependabot/source.go

@@ -12,7 +12,7 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-var commitRegex = regexp.MustCompile(`(?m)[Bb]ump (\S+)(?: from (\S+))?(?: to (\S+))?(?:.+\([#!](\d+)\)$)?`)
+var commitRegex = regexp.MustCompile(`(?m)[Bb]ump (\S+)(?: from (\S+))?(?: to (\S+))?(?:.+\([#!](\d+)\)$)?(?:")?`)
 
 const dependabotAuthor = "dependabot"
 
@@ -28,6 +28,7 @@ func NewSource(tagsVersionGetter git.TagsVersionGetter, commitsGetter git.Commit
 	}
 }
 
+//nolint:gocyclo,cyclop
 func (r Source) Changelog() (*changelog.Changelog, error) {
 	lastHash, err := r.tagsVersionGetter.LastVersionHash()
 	if err != nil {
@@ -46,12 +47,19 @@ func (r Source) Changelog() (*changelog.Changelog, error) {
 
 	for _, c := range gitCommits {
 		commitLine := strings.Split(c.Message, "\n")[0]
-		if !strings.Contains(strings.ToLower(c.Author), dependabotAuthor) {
-			log.Debugf("skipping commit as it is not authored by dependabot\n> %q", commitLine)
+		isRevert := strings.HasPrefix(strings.ToLower(commitLine), "revert")
+		if !strings.Contains(strings.ToLower(c.Author), dependabotAuthor) && !isRevert {
+			log.Debugf("skipping commit as it is neither authored by dependabot nor a revert\n> %q", commitLine)
 			continue
 		}
 
-		capturingGroups := commitRegex.FindStringSubmatch(c.Message)
+		if isRevert {
+			// Revert commits usually surround the original commit line with double quotes.
+			// We could complicate the regex further, but stripping the quotes is allegedly easier.
+			commitLine = strings.Trim(commitLine, `"`)
+		}
+
+		capturingGroups := commitRegex.FindStringSubmatch(commitLine)
 		if len(capturingGroups) == 0 {
 			log.Debugf("skipping commit  %s as it does not match dependabot pattern and no information can be retrieved", c.Message)
 			continue
@@ -67,6 +75,10 @@ func (r Source) Changelog() (*changelog.Changelog, error) {
 			log.Debugf("skipping dependency %q as it doesn't conform to semver %v", dependencyName, dependencyTo)
 		}
 
+		if isRevert {
+			dependencyTo, dependencyFrom = dependencyFrom, dependencyTo
+		}
+
 		dependencies = append(dependencies, changelog.Dependency{
 			Name: dependencyName,
 			From: dependencyFrom,

src/changelog/sources/dependabot/source_test.go

@@ -263,6 +263,11 @@ Bumps [actions/github-script](https://github.com/actions/github-script) from 4.0
 			errExpected: errRandomError,
 			expected:    nil,
 		},
+		{
+			name:     "Revert_Matching_Commit_Single_Root_Minor",
+			commit:   git.Commit{Message: "Revert \"chore(deps): bump my-dep from 1.2.3 to 2.0.0\"", Author: "Not-a-bot"},
+			expected: []changelog.Dependency{{Name: "my-dep", From: semver.MustParse("2.0.0"), To: semver.MustParse("1.2.3")}},
+		},
 	} {
 		tc := tc
 		if tc.name == "" {

src/changelog/sources/renovate/source.go

@@ -26,6 +26,7 @@ func NewSource(tagsVersionGetter git.TagsVersionGetter, commitsGetter git.Commit
 	}
 }
 
+//nolint:gocyclo,cyclop
 func (r Source) Changelog() (*changelog.Changelog, error) {
 	lastHash, err := r.tagsVersionGetter.LastVersionHash()
 	if err != nil {
@@ -47,8 +48,9 @@ func (r Source) Changelog() (*changelog.Changelog, error) {
 		var commitDependencies []changelog.Dependency
 
 		commitLine := strings.Split(c.Message, "\n")[0]
-		if !strings.Contains(strings.ToLower(c.Author), renovateAuthor) {
-			log.Debugf("skipping commit as it is not authored by renovate\n> %q", commitLine)
+		isRevert := strings.HasPrefix(strings.ToLower(commitLine), "revert")
+		if !strings.Contains(strings.ToLower(c.Author), renovateAuthor) && !isRevert {
+			log.Debugf("skipping commit as it is neither authored by renovate nor a revert\n> %q", commitLine)
 			continue
 		}
 
@@ -66,6 +68,13 @@ func (r Source) Changelog() (*changelog.Changelog, error) {
 			commitDependencies = append(commitDependencies, r.titleDependencies(commitLine)...)
 		}
 
+		if isRevert {
+			// If this is a revert commit, swap to/from for all commitDependencies.
+			for i := range commitDependencies {
+				commitDependencies[i].From, commitDependencies[i].To = commitDependencies[i].To, commitDependencies[i].From
+			}
+		}
+
 		// Add commit hash and copy to dependencies
 		for _, dep := range commitDependencies {
 			dep.Meta.Commit = c.Hash

src/changelog/sources/renovate/source_test.go

@@ -41,7 +41,7 @@ func (c *commitsGetterMock) Commits(_ string) ([]git.Commit, error) {
 	return commits, nil
 }
 
-//nolint:funlen
+//nolint:funlen,maintidx
 func TestSource_Source(t *testing.T) {
 	t.Parallel()
 	for _, tc := range []struct {
@@ -196,6 +196,19 @@ func TestSource_Source(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:          "Matches_Reverts",
+			defaultAuthor: "not-a-bot",
+			commitMessages: []git.Commit{
+				{Message: "Revert \"update noprefix to v1.2.3\""},
+			},
+			expectedDependencies: []changelog.Dependency{
+				{
+					Name: "noprefix",
+					From: semver.MustParse("v1.2.3"),
+				},
+			},
+		},
 		{
 			name:          "Error_No_Releases",
 			defaultAuthor: "renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>",