fix(changelog): group regexps

Fix the regular expressions used in changelog group processing to valid
golang (RE2) regexps. These previously used PCRE character class \w which
is not supported in RE2 which is what golang regexp uses.

Document that format matches not just title as some may thing but
the format "<abbrev-commit> <title-commit>".

This also include "!" as defined by conventional commits.

.goreleaser.yaml

@@ -53,16 +53,16 @@ changelog:
     - go mod tidy
   groups:
     - title: Dependency updates
-      regexp: "^.*(feat|fix)\\(deps\\)*:+.*$"
+      regexp: '^[0-9a-h]+ (feat|fix)\(deps\)!?:.+$'
       order: 300
     - title: 'New Features'
-      regexp: "^.*feat[(\\w)]*:+.*$"
+      regexp: '^[0-9a-h]+ feat(\([[:word:]]+\))??!?:.+$'
       order: 100
     - title: 'Bug fixes'
-      regexp: "^.*fix[(\\w)]*:+.*$"
+      regexp: '^[0-9a-h]+ fix(\([[:word:]]+\))??!?:.+$'
       order: 200
     - title: 'Documentation updates'
-      regexp: "^.*docs[(\\w)]*:+.*$"
+      regexp: ^[0-9a-h]+ doc(\([[:word:]]+\))??!?:.+$
       order: 400
     - title: Other work
       order: 9999

internal/pipe/changelog/changelog_test.go

@@ -638,12 +638,12 @@ func TestGroup(t *testing.T) {
 				},
 				{
 					Title:  "Features",
-					Regexp: "^.*feat[(\\w)]*:+.*$",
+					Regexp: `^[0-9a-h]+ feat(\([[:word:]]+\))??!?:.+$`,
 					Order:  0,
 				},
 				{
 					Title:  "Bug Fixes",
-					Regexp: "^.*bug[(\\w)]*:+.*$",
+					Regexp: `^[0-9a-h]+ bug(\([[:word:]]+\))??!?:.+$`,
 					Order:  1,
 				},
 				{
@@ -680,13 +680,13 @@ func TestGroupBadRegex(t *testing.T) {
 			Groups: []config.ChangeLogGroup{
 				{
 					Title:  "Something",
-					Regexp: "^.*feat[(\\w", // unterminated regex
+					Regexp: "^.*feat[a-z", // unterminated regex
 				},
 			},
 		},
 	})
 	ctx.Git.CurrentTag = "v0.0.2"
-	require.EqualError(t, Pipe{}.Run(ctx), `failed to group into "Something": error parsing regexp: missing closing ]: `+"`"+`[(\w`+"`")
+	require.EqualError(t, Pipe{}.Run(ctx), "failed to group into \"Something\": error parsing regexp: missing closing ]: `[a-z`")
 }
 
 func TestChangelogFormat(t *testing.T) {

www/docs/customization/changelog.md

@@ -51,14 +51,15 @@ changelog:
   # Order value defines the order of the groups.
   # Proving no regex means all commits will be grouped under the default group.
   # Groups are disabled when using github-native, as it already groups things by itself.
+  # Matches are performed against strings of the form: "<abbrev-commit> <title-commit>".
   #
   # Default is no groups.
   groups:
     - title: Features
-      regexp: "^.*feat[(\\w)]*:+.*$"
+      regexp: '^[0-9a-h]+ feat(\([[:word:]]+\))??!?:.+$'
       order: 0
     - title: 'Bug fixes'
-      regexp: "^.*fix[(\\w)]*:+.*$"
+      regexp: '^[0-9a-h]+ bug(\([[:word:]]+\))??!?:.+$'
       order: 1
     - title: Others
       order: 999