Warn about duplicate DESCR files

Suggested by gdt@.

https://mail-index.netbsd.org/pkgsrc-users/2024/01/19/msg038803.html

v23/distinfo_test.go

@@ -721,6 +721,9 @@ func (s *Suite) Test_distinfoLinesChecker_checkGlobalDistfileMismatch(c *check.C
  "ERROR: ~/category/package1/distinfo:5: "+
  "Expected BLAKE2s, SHA512, Size checksums for \"patch-4.2.tar.gz\", got SHA512.",
 
+ "WARN: ~/category/package2/DESCR: DESCR file is the same "+
+ "as \"../../category/package1/DESCR\".",
+
  "ERROR: ~/category/package2/distinfo:3: "+
  "Expected BLAKE2s, SHA512, Size checksums for \"distfile-1.0.tar.gz\", got SHA512.",
  "ERROR: ~/category/package2/distinfo:3: "+
@@ -734,7 +737,7 @@ func (s *Suite) Test_distinfoLinesChecker_checkGlobalDistfileMismatch(c *check.C
  "The SHA512 hash for encoding-error.tar.gz contains a non-hex character.",
 
  "WARN: ~/licenses/gnu-gpl-v2: This license seems to be unused.",
- "8 errors and 1 warning found.",
+ "8 errors and 2 warnings found.",
  t.Shquote("(Run \"pkglint -e -r -Wall -Call %s\" to show explanations.)", "."))
 
  // Ensure that hex.DecodeString does not waste memory here.

v23/pkglint.go

@@ -1,6 +1,7 @@
 package pkglint
 
 import (
+ "crypto/sha1"
  "fmt"
  "github.com/rillig/pkglint/v23/getopt"
  "github.com/rillig/pkglint/v23/histogram"
@@ -635,6 +636,7 @@ func (p *Pkglint) checkReg(filename CurrPath, basename RelPath, depth int, pkg *
  case basename.HasPrefixText("DESCR"):
  if lines := Load(filename, NotEmpty|LogErrors); lines != nil {
  CheckLinesDescr(lines)
+ G.InterPackage.CheckDuplicateDescr(filename)
  }
 
  case basename == "distinfo":
@@ -864,17 +866,21 @@ func (p *Pkglint) Abs(filename CurrPath) CurrPath {
  return filename.Clean()
 }
 
+// InterPackage collects data from the inter-package analysis.
+// It is most useful when running pkglint on a complete pkgsrc installation.
 type InterPackage struct {
  hashes map[string]*Hash // Maps "alg:filename" => hash (inter-package check).
  usedLicenses map[string]struct{} // Maps "license name" => true (inter-package check).
  bl3Names map[string]Location // Maps buildlink3 identifiers to their first occurrence.
+ descr map[[sha1.Size]byte][]CurrPath
 }
 
 func (ip *InterPackage) Enable() {
  *ip = InterPackage{
  make(map[string]*Hash),
  make(map[string]struct{}),
- make(map[string]Location)}
+ make(map[string]Location),
+ make(map[[sha1.Size]byte][]CurrPath)}
 
  // This is the only license that is added by an infrastructure file,
  // mk/djbware.mk. The correct way to handle this situation would be
@@ -921,3 +927,30 @@ func (ip *InterPackage) Bl3(name string, loc *Location) *Location {
  ip.bl3Names[name] = *loc
  return nil
 }
+
+func (ip *InterPackage) CheckDuplicateDescr(filename CurrPath) {
+ descr := ip.descr
+ if descr == nil {
+ return
+ }
+ b, err := os.ReadFile(filename.String())
+ if err != nil {
+ return
+ }
+ h := sha1.Sum(b)
+ existing := descr[h]
+ descr[h] = append(existing, filename)
+ if len(existing) == 0 {
+ return
+ }
+ line := NewLineWhole(filename)
+ line.Warnf("DESCR file is the same as %q.",
+ line.Rel(existing[len(existing)-1]))
+ line.Explain(
+ "Each DESCR file should be unique,",
+ "to help the user choose the most appropriate package.",
+ "",
+ "If two packages really need the exact same DESCR file,",
+ "create a single DESCR file for both",
+ "and refer to it via DESCR_SRC.")
+}

v23/pkglint_test.go

@@ -1511,6 +1511,8 @@ func (s *Suite) Test_InterPackage_Bl3__same_identifier(c *check.C) {
  "can be replaced with the simpler \"S,^,,\".",
  "NOTE: category/package1/Makefile:4: The modifier \"@v@${v}@\" "+
  "can be replaced with the simpler \"=\".",
+ "WARN: category/package2/DESCR: DESCR file is "+
+ "the same as \"../../category/package1/DESCR\".",
  "NOTE: category/package2/Makefile:4: The modifier \"@v@${v}@\" "+
  "can be replaced with the simpler \"S,^,,\".",
  "NOTE: category/package2/Makefile:4: The modifier \"@v@${v}@\" "+

v23/pkgsrc_test.go

@@ -834,10 +834,12 @@ func (s *Suite) Test_Pkgsrc_checkToplevelUnusedLicenses(c *check.C) {
  t.Main("-r", "-Cglobal", ".")
 
  t.CheckOutputLines(
+ "WARN: ~/category/package2/DESCR: DESCR file is the same "+
+ "as \"../../category/package/DESCR\".",
  "ERROR: ~/category/package2/Makefile:11: License file ../../licenses/missing does not exist.",
  "WARN: ~/licenses/gnu-gpl-v2: This license seems to be unused.", // Added by Tester.SetUpPkgsrc
  "WARN: ~/licenses/gnu-gpl-v3: This license seems to be unused.",
- "1 error and 2 warnings found.",
+ "1 error and 3 warnings found.",
  t.Shquote("(Run \"pkglint -e -r -Cglobal %s\" to show explanations.)", "."))
 }