From: Sergey Matveev <stargrave@stargrave.org>
Date: Fri, 16 Jan 2026 12:12:18 +0000 (+0300)
Subject: Warn if non-top target does not write anything
X-Git-Tag: v2.9.0~1
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=e42f5fc4b78400781b86bb421757d2820cbd6391;p=goredo.git

Warn if non-top target does not write anything
---

diff --git a/doc/INSTALL b/doc/INSTALL
index 9b26ded..c488783 100644
--- a/doc/INSTALL
+++ b/doc/INSTALL
@@ -11,7 +11,7 @@ Possibly goredo package already exists for your distribution:
 
 Preferable way is to [Download] tarball with the signature from website:
 
-    $ v=2.8.0
+    $ v=2.9.0
     $ [fetch|wget] http://www.goredo.cypherpunks.su/download/goredo-$v.tar.zst
     $ [fetch|wget] http://www.goredo.cypherpunks.su/download/goredo-$v.tar.zst.{asc,sig,cm}
     [Integrity] verify
diff --git a/doc/NEWS b/doc/NEWS
index 9044072..e6015e1 100644
--- a/doc/NEWS
+++ b/doc/NEWS
@@ -1,3 +1,8 @@
+A 2.9.0
+2.9.0
+    * Warn if non-top target did not write anything.
+      Idea was borrowed from redo-sh.
+
 A 2.8.0
 2.8.0
     * Fix always-OOD .do-targets with nearby default.do.
diff --git a/doc/cmd/redo-ifchange b/doc/cmd/redo-ifchange
index 8976135..f907f92 100644
--- a/doc/cmd/redo-ifchange
+++ b/doc/cmd/redo-ifchange
@@ -8,6 +8,8 @@ Pay attention that redo-ifchange enables parallel builds of the given
 targets, but ordinary redo is not: it builds specified targets
 sequentially and stops when error happens.
 
+It will warn if non-top target did not write anything.
+
 A [Env] REDO_STOP_IF_MODIFIED
 If redo sees some target modified externally, then by default it warns
 user about that, does not build that target, but continues the build
diff --git a/run.go b/run.go
index 412e895..d043d1a 100644
--- a/run.go
+++ b/run.go
@@ -745,6 +745,9 @@ func runScript(tgt *Tgt, errs chan error, forced, traced bool) error {
 
 		// Do we need to ifcreate it, or ifchange with renaming?
 		if fd == nil {
+			if Level > 0 {
+				tracef(CWarn, "%s: nothing written to target", tgt)
+			}
 			os.Remove(tgt.a)
 			err = ifcreate(fdDepW, fdDep.Name(), tgtT)
 			if err != nil {
diff --git a/t/goredo-build-uuid-for-fdood.t b/t/goredo-build-uuid-for-fdood.t
index 2930ef0..d0d7ba1 100755
--- a/t/goredo-build-uuid-for-fdood.t
+++ b/t/goredo-build-uuid-for-fdood.t
@@ -6,9 +6,12 @@ export REDO_TOP_DIR="`pwd`" REDO_NO_PROGRESS=1
 
 echo redo-ifchange l3 l2 >l1.do
 echo redo-ifchange l3 >l2.do
+echo echo ok >>l1.do
+echo echo ok >>l2.do
 cat >l3.do <<EOF
 sleep 1
 touch \$(date +%s).touch
+echo ok
 EOF
 
 redo -j 1 l1
diff --git a/t/goredo-double-consideration.t b/t/goredo-double-consideration.t
index f915147..55de358 100755
--- a/t/goredo-double-consideration.t
+++ b/t/goredo-double-consideration.t
@@ -4,7 +4,10 @@ test_description="Do not fail if two always-ed targets run simultaneously"
 . $SHARNESS_TEST_SRCDIR/sharness.sh
 export REDO_TOP_DIR="`pwd`" REDO_NO_PROGRESS=1
 
-echo redo-ifchange version.h >all.do
+cat >all.do <<EOF
+redo-ifchange version.h
+echo ok
+EOF
 cat >version.h.do <<EOF
 redo-ifchange date version version.h.in
 VERSION=\$(cat version)
diff --git a/t/redo-sh.tests/nothing_written_1/test b/t/redo-sh.tests/nothing_written_1/test
new file mode 100755
index 0000000..36a3847
--- /dev/null
+++ b/t/redo-sh.tests/nothing_written_1/test
@@ -0,0 +1,10 @@
+#!/bin/sh -eu
+# A non-top-level build rule not writing to a target must yield a warning.
+
+>all.do printf 'redo-ifchange a
+'
+
+>a.do :
+
+2>stderr redo
+<stderr grep -q 'a: nothing written to target'
diff --git a/t/redo-sh.tests/nothing_written_2/test b/t/redo-sh.tests/nothing_written_2/test
new file mode 100755
index 0000000..9919483
--- /dev/null
+++ b/t/redo-sh.tests/nothing_written_2/test
@@ -0,0 +1,14 @@
+#!/bin/sh -eu
+# Each non-top-level build rule not writing to a target must yield a warning.
+
+>all.do printf 'redo-ifchange a
+'
+
+>a.do printf 'redo-ifchange b
+'
+
+>b.do :
+
+2>stderr redo
+<stderr grep -q 'a: nothing written to target'
+<stderr grep -q 'b: nothing written to target'
diff --git a/t/redo-sh.tests/parallel_1/test b/t/redo-sh.tests/parallel_1/test
index 254b717..1930eab 100755
--- a/t/redo-sh.tests/parallel_1/test
+++ b/t/redo-sh.tests/parallel_1/test
@@ -10,6 +10,7 @@ EOF
 
 >default.do cat <<EOF
 redo-always
+date +%s
 sleep 1
 EOF
 
diff --git a/t/redosh-nothing_written_1.t b/t/redosh-nothing_written_1.t
new file mode 120000
index 0000000..3f2c214
--- /dev/null
+++ b/t/redosh-nothing_written_1.t
@@ -0,0 +1 @@
+redo-sh.tests/wrapper.rc
\ No newline at end of file
diff --git a/t/redosh-nothing_written_2.t b/t/redosh-nothing_written_2.t
new file mode 120000
index 0000000..3f2c214
--- /dev/null
+++ b/t/redosh-nothing_written_2.t
@@ -0,0 +1 @@
+redo-sh.tests/wrapper.rc
\ No newline at end of file
diff --git a/usage.go b/usage.go
index 399e85b..d18f8f1 100644
--- a/usage.go
+++ b/usage.go
@@ -24,7 +24,7 @@ import (
 )
 
 const (
-	Version  = "2.8.1"
+	Version  = "2.9.0"
 	Warranty = `Copyright (C) 2020-2026 Sergey Matveev
 
 This program is free software: you can redistribute it and/or modify