[PATCH 0/4] doc lint: fix recent regression, make non-.PHONY

[PATCH 0/4] doc lint: fix recent regression, make non-.PHONY

[Ævar Arnfjörð Bjarmason]

Recent patches of mine broke the "check-docs" target by using
;-chaining instead of &&-chaining, d'oh! That's currently hiding a
breakage in "seen"[1], sorry!

In 1/4 that's fixed, 2/4 emits errors to STDERR instead of STDOUT, 3/4
speeds up the target by ~2x by skipping unnecessary work, and 4/4
makes it non-.PHONY.

The technique in 4/4 of exhaustively generating a dependency graph
per-file is something I'm also using in some yet-to-be-submitted
series of other Makefile fixes, that similarly speed things up.

1. https://lore.kernel.org/git/87lf2ueafl.fsf@evledraar.gmail.com/

Ævar Arnfjörð Bjarmason (4):
  doc lint: fix error-hiding regression
  doc lint: emit errors on STDERR
  doc build: speed up "make lint-docs"
  doc lint: make "lint-docs" non-.PHONY

 Documentation/.gitignore                  |  1 +
 Documentation/Makefile                    | 67 ++++++++++++++++++++---
 Documentation/lint-gitlink.perl           | 10 ++--
 Documentation/lint-man-end-blurb.perl     |  2 +-
 Documentation/lint-man-section-order.perl |  2 +-
 5 files changed, 69 insertions(+), 13 deletions(-)

-- 
2.33.1.1338.g20da966911a

[PATCH 1/4] doc lint: fix error-hiding regression

[Ævar Arnfjörð Bjarmason]

Fix the broken "make lint-docs" (or "make check-docs" at the
top-level) target, which has been broken since my cafd9828e89 (doc
lint: lint and fix missing "GIT" end sections, 2021-04-09).

The CI for "seen" is emitting an error about a broken gitlink, but due
to there being 3x scripts chained via ";" instead of "&&" we're not
carrying forward the non-zero exit code.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Documentation/Makefile | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index f5605b7767f..78324934d9f 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -461,9 +461,9 @@ lint-docs::
 		$(HOWTO_TXT) $(DOC_DEP_TXT) \
 		--section=1 $(MAN1_TXT) \
 		--section=5 $(MAN5_TXT) \
-		--section=7 $(MAN7_TXT); \
-	$(PERL_PATH) lint-man-end-blurb.perl $(MAN_TXT); \
-	$(PERL_PATH) lint-man-section-order.perl $(MAN_TXT);
+		--section=7 $(MAN7_TXT) && \
+	$(PERL_PATH) lint-man-end-blurb.perl $(MAN_TXT) && \
+	$(PERL_PATH) lint-man-section-order.perl $(MAN_TXT)
 
 ifeq ($(wildcard po/Makefile),po/Makefile)
 doc-l10n install-l10n::
-- 
2.33.1.1338.g20da966911a

[PATCH 2/4] doc lint: emit errors on STDERR

[Ævar Arnfjörð Bjarmason]

Have all of the scripts invoked by "make check-docs" emit their output
on STDERR. This does not currently matter due to the way we're
invoking them, but will in a subsequent change. It's a good idea to do
this in any case for consistency with other tools we invoke.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Documentation/lint-gitlink.perl           | 4 ++--
 Documentation/lint-man-end-blurb.perl     | 2 +-
 Documentation/lint-man-section-order.perl | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/Documentation/lint-gitlink.perl b/Documentation/lint-gitlink.perl
index b22a367844a..076701ccfac 100755
--- a/Documentation/lint-gitlink.perl
+++ b/Documentation/lint-gitlink.perl
@@ -30,8 +30,8 @@ sub report {
 	my ($pos, $line, $target, $msg) = @_;
 	substr($line, $pos) = "' <-- HERE";
 	$line =~ s/^\s+//;
-	print "$ARGV:$.: error: $target: $msg, shown with 'HERE' below:\n";
-	print "$ARGV:$.:\t'$line\n";
+	print STDERR "$ARGV:$.: error: $target: $msg, shown with 'HERE' below:\n";
+	print STDERR "$ARGV:$.:\t'$line\n";
 	$exit_code = 1;
 }
 
diff --git a/Documentation/lint-man-end-blurb.perl b/Documentation/lint-man-end-blurb.perl
index d69312e5db5..6bdb13ad9fd 100755
--- a/Documentation/lint-man-end-blurb.perl
+++ b/Documentation/lint-man-end-blurb.perl
@@ -6,7 +6,7 @@
 my $exit_code = 0;
 sub report {
 	my ($target, $msg) = @_;
-	print "error: $target: $msg\n";
+	print STDERR "error: $target: $msg\n";
 	$exit_code = 1;
 }
 
diff --git a/Documentation/lint-man-section-order.perl b/Documentation/lint-man-section-order.perl
index b05f9156dd9..425377dfeb7 100755
--- a/Documentation/lint-man-section-order.perl
+++ b/Documentation/lint-man-section-order.perl
@@ -46,7 +46,7 @@
 my $exit_code = 0;
 sub report {
 	my ($msg) = @_;
-	print "$ARGV:$.: $msg\n";
+	print STDERR "$ARGV:$.: $msg\n";
 	$exit_code = 1;
 }
 
-- 
2.33.1.1338.g20da966911a

[PATCH 3/4] doc build: speed up "make lint-docs"

[Ævar Arnfjörð Bjarmason]

Extend the trick we use to speed up the "clean" target to also extend
to the "lint-docs" target. See 54df87555b1 (Documentation/Makefile:
conditionally include doc.dep, 2020-12-08) for the "clean"
implementation.

The "doc-lint" target only depends on *.txt files, so we don't need to
generate GIT-VERSION-FILE etc. if that's all we're doing. This makes
the "make lint-docs" target more than 2x as fast:

$ git show HEAD~:Documentation/Makefile >Makefile.old
$ hyperfine -L f ",.old" 'make -f Makefile{f} lint-docs'
Benchmark #1: make -f Makefile lint-docs
  Time (mean ± σ):     100.2 ms ±   1.3 ms    [User: 93.7 ms, System: 6.7 ms]
  Range (min … max):    98.4 ms … 103.1 ms    29 runs

Benchmark #2: make -f Makefile.old lint-docs
  Time (mean ± σ):     220.0 ms ±  20.0 ms    [User: 206.0 ms, System: 18.0 ms]
  Range (min … max):   206.6 ms … 267.5 ms    11 runs

Summary
  'make -f Makefile lint-docs' ran
    2.19 ± 0.20 times faster than 'make -f Makefile.old lint-docs'

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Documentation/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index 78324934d9f..e8e54e053a6 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -284,7 +284,7 @@ install-html: html
 ../GIT-VERSION-FILE: FORCE
 	$(QUIET_SUBDIR0)../ $(QUIET_SUBDIR1) GIT-VERSION-FILE
 
-ifneq ($(MAKECMDGOALS),clean)
+ifneq ($(filter-out lint-docs clean,$(MAKECMDGOALS)),)
 -include ../GIT-VERSION-FILE
 endif
 
-- 
2.33.1.1338.g20da966911a

[PATCH 4/4] doc lint: make "lint-docs" non-.PHONY

[Ævar Arnfjörð Bjarmason]

Speed up the "lint-docs" target by making it non-.PHONY. Similar to my
c234e8a0ecf (Makefile: make the "sparse" target non-.PHONY,
2021-09-23). We'll now create empty files corresponding to a
dependency graph for each of these lint scripts.

This speeds things up a bit[1], and makes the output correspond to any
in-tree changes we have:

    $ touch git-add.txt; make lint-docs; make lint-docs
        GEN cmd-list.made
        GEN doc.dep
        LINT GITLINK git-add.txt
        LINT MAN END git-add.txt
        LINT MAN SEC git-add.txt
    make: Nothing to be done for 'lint-docs'.

As with the "sparse" target changes this has a hard dependency on the
use of ".DELETE_ON_ERROR" in the Makefile, added here in
db10fc6c09f (doc: simplify Makefile using .DELETE_ON_ERROR,
2021-05-21). This method also depends on the output for us emitting
any errors on STDERR (fixed in a preceding commit), as well us these
scripts exiting with non-zero on any errors (which they were already
doing).

1.
$ git show HEAD~:Documentation/Makefile >Makefile.old
$ hyperfine --warmup 2 -L f ",.old" 'make -j1 -f Makefile{f} lint-docs'
Benchmark #1: make -j1 -f Makefile lint-docs
  Time (mean ± σ):      60.8 ms ±   1.4 ms    [User: 58.7 ms, System: 2.5 ms]
  Range (min … max):    58.9 ms …  64.0 ms    48 runs

Benchmark #2: make -j1 -f Makefile.old lint-docs
  Time (mean ± σ):      84.0 ms ±   1.5 ms    [User: 78.6 ms, System: 5.7 ms]
  Range (min … max):    81.8 ms …  87.8 ms    35 runs

Summary
  'make -j1 -f Makefile lint-docs' ran
    1.38 ± 0.04 times faster than 'make -j1 -f Makefile.old lint-docs'

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Documentation/.gitignore        |  1 +
 Documentation/Makefile          | 65 ++++++++++++++++++++++++++++++---
 Documentation/lint-gitlink.perl |  6 ++-
 3 files changed, 64 insertions(+), 8 deletions(-)

diff --git a/Documentation/.gitignore b/Documentation/.gitignore
index 9022d483554..1c3771e7d72 100644
--- a/Documentation/.gitignore
+++ b/Documentation/.gitignore
@@ -14,4 +14,5 @@ manpage-base-url.xsl
 SubmittingPatches.txt
 tmp-doc-diff/
 GIT-ASCIIDOCFLAGS
+/.build/
 /GIT-EXCLUDED-PROGRAMS
diff --git a/Documentation/Makefile b/Documentation/Makefile
index e8e54e053a6..46c91f32566 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -225,6 +225,7 @@ endif
 
 ifneq ($(findstring $(MAKEFLAGS),s),s)
 ifndef V
+	QUIET		= @
 	QUIET_ASCIIDOC	= @echo '   ' ASCIIDOC $@;
 	QUIET_XMLTO	= @echo '   ' XMLTO $@;
 	QUIET_DB2TEXI	= @echo '   ' DB2TEXI $@;
@@ -232,11 +233,15 @@ ifndef V
 	QUIET_DBLATEX	= @echo '   ' DBLATEX $@;
 	QUIET_XSLTPROC	= @echo '   ' XSLTPROC $@;
 	QUIET_GEN	= @echo '   ' GEN $@;
-	QUIET_LINT	= @echo '   ' LINT $@;
 	QUIET_STDERR	= 2> /dev/null
 	QUIET_SUBDIR0	= +@subdir=
 	QUIET_SUBDIR1	= ;$(NO_SUBDIR) echo '   ' SUBDIR $$subdir; \
 			  $(MAKE) $(PRINT_DIR) -C $$subdir
+
+	QUIET_LINT_GITLINK	= @echo '   ' LINT GITLINK $<;
+	QUIET_LINT_MANSEC	= @echo '   ' LINT MAN SEC $<;
+	QUIET_LINT_MANEND	= @echo '   ' LINT MAN END $<;
+
 	export V
 endif
 endif
@@ -343,6 +348,7 @@ GIT-ASCIIDOCFLAGS: FORCE
             fi
 
 clean:
+	$(RM) -rf .build/
 	$(RM) *.xml *.xml+ *.html *.html+ *.1 *.5 *.7
 	$(RM) *.texi *.texi+ *.texi++ git.info gitman.info
 	$(RM) *.pdf
@@ -456,14 +462,61 @@ quick-install-html: require-htmlrepo
 print-man1:
 	@for i in $(MAN1_TXT); do echo $$i; done
 
-lint-docs::
-	$(QUIET_LINT)$(PERL_PATH) lint-gitlink.perl \
+## Lint: Common
+.build:
+	$(QUIET)mkdir $@
+.build/lint-docs: | .build
+	$(QUIET)mkdir $@
+
+## Lint: gitlink
+.build/lint-docs/gitlink: | .build/lint-docs
+	$(QUIET)mkdir $@
+.build/lint-docs/gitlink/howto: | .build/lint-docs
+	$(QUIET)mkdir $@
+.build/lint-docs/gitlink/config: | .build/lint-docs
+	$(QUIET)mkdir $@
+LINT_DOCS_GITLINK = $(patsubst %.txt,.build/lint-docs/gitlink/%.ok,$(HOWTO_TXT) $(DOC_DEP_TXT))
+$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink
+$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink/howto
+$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink/config
+$(LINT_DOCS_GITLINK): lint-gitlink.perl
+$(LINT_DOCS_GITLINK): .build/lint-docs/gitlink/%.ok: %.txt
+	$(QUIET_LINT_GITLINK)$(PERL_PATH) lint-gitlink.perl \
+		$< \
 		$(HOWTO_TXT) $(DOC_DEP_TXT) \
 		--section=1 $(MAN1_TXT) \
 		--section=5 $(MAN5_TXT) \
-		--section=7 $(MAN7_TXT) && \
-	$(PERL_PATH) lint-man-end-blurb.perl $(MAN_TXT) && \
-	$(PERL_PATH) lint-man-section-order.perl $(MAN_TXT)
+		--section=7 $(MAN7_TXT) >$@
+.PHONY: lint-docs-gitlink
+lint-docs-gitlink: $(LINT_DOCS_GITLINK)
+
+## Lint: man-end-blurb
+.build/lint-docs/man-end-blurb: | .build/lint-docs
+	$(QUIET)mkdir $@
+LINT_DOCS_MAN_END_BLURB = $(patsubst %.txt,.build/lint-docs/man-end-blurb/%.ok,$(MAN_TXT))
+$(LINT_DOCS_MAN_END_BLURB): | .build/lint-docs/man-end-blurb
+$(LINT_DOCS_MAN_END_BLURB): lint-man-end-blurb.perl
+$(LINT_DOCS_MAN_END_BLURB): .build/lint-docs/man-end-blurb/%.ok: %.txt
+	$(QUIET_LINT_MANEND)$(PERL_PATH) lint-man-end-blurb.perl $< >$@
+.PHONY: lint-docs-man-end-blurb
+lint-docs-man-end-blurb: $(LINT_DOCS_MAN_END_BLURB)
+
+## Lint: man-section-order
+.build/lint-docs/man-section-order: | .build/lint-docs
+	$(QUIET)mkdir $@
+LINT_DOCS_MAN_SECTION_ORDER = $(patsubst %.txt,.build/lint-docs/man-section-order/%.ok,$(MAN_TXT))
+$(LINT_DOCS_MAN_SECTION_ORDER): | .build/lint-docs/man-section-order
+$(LINT_DOCS_MAN_SECTION_ORDER): lint-man-section-order.perl
+$(LINT_DOCS_MAN_SECTION_ORDER): .build/lint-docs/man-section-order/%.ok: %.txt
+	$(QUIET_LINT_MANSEC)$(PERL_PATH) lint-man-section-order.perl $< >$@
+.PHONY: lint-docs-man-section-order
+lint-docs-man-section-order: $(LINT_DOCS_MAN_SECTION_ORDER)
+
+## Lint: list of targets above
+.PHONY: lint-docs
+lint-docs: lint-docs-gitlink
+lint-docs: lint-docs-man-end-blurb
+lint-docs: lint-docs-man-section-order
 
 ifeq ($(wildcard po/Makefile),po/Makefile)
 doc-l10n install-l10n::
diff --git a/Documentation/lint-gitlink.perl b/Documentation/lint-gitlink.perl
index 076701ccfac..1c61dd9512b 100755
--- a/Documentation/lint-gitlink.perl
+++ b/Documentation/lint-gitlink.perl
@@ -5,11 +5,12 @@
 
 # Parse arguments, a simple state machine for input like:
 #
-# howto/*.txt config/*.txt --section=1 git.txt git-add.txt [...] --to-lint git-add.txt a-file.txt [...]
+# <file-to-check.txt> <valid-files-to-link-to> --section=1 git.txt git-add.txt [...] --to-lint git-add.txt a-file.txt [...]
 my %TXT;
 my %SECTION;
 my $section;
 my $lint_these = 0;
+my $to_check = shift @ARGV;
 for my $arg (@ARGV) {
 	if (my ($sec) = $arg =~ /^--section=(\d+)$/s) {
 		$section = $sec;
@@ -36,7 +37,8 @@ sub report {
 }
 
 @ARGV = sort values %TXT;
-die "BUG: Nothing to process!" unless @ARGV;
+die "BUG: No list of valid linkgit:* files given" unless @ARGV;
+@ARGV = $to_check;
 while (<>) {
 	my $line = $_;
 	while ($line =~ m/linkgit:((.*?)\[(\d)\])/g) {
-- 
2.33.1.1338.g20da966911a

Re: [PATCH 3/4] doc build: speed up "make lint-docs"

[Junio C Hamano]

Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:

> Extend the trick we use to speed up the "clean" target to also extend
> to the "lint-docs" target. See 54df87555b1 (Documentation/Makefile:
> conditionally include doc.dep, 2020-12-08) for the "clean"
> implementation.
>
> The "doc-lint" target only depends on *.txt files, so we don't need to
> generate GIT-VERSION-FILE etc. if that's all we're doing. This makes
> the "make lint-docs" target more than 2x as fast:

Nice. 0.2s down to 0.1 is a 2x speedup.

> $ git show HEAD~:Documentation/Makefile >Makefile.old
> $ hyperfine -L f ",.old" 'make -f Makefile{f} lint-docs'
> Benchmark #1: make -f Makefile lint-docs
>   Time (mean ± σ):     100.2 ms ±   1.3 ms    [User: 93.7 ms, System: 6.7 ms]
>   Range (min … max):    98.4 ms … 103.1 ms    29 runs
>
> Benchmark #2: make -f Makefile.old lint-docs
>   Time (mean ± σ):     220.0 ms ±  20.0 ms    [User: 206.0 ms, System: 18.0 ms]
>   Range (min … max):   206.6 ms … 267.5 ms    11 runs
>
> Summary
>   'make -f Makefile lint-docs' ran
>     2.19 ± 0.20 times faster than 'make -f Makefile.old lint-docs'
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  Documentation/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/Makefile b/Documentation/Makefile
> index 78324934d9f..e8e54e053a6 100644
> --- a/Documentation/Makefile
> +++ b/Documentation/Makefile
> @@ -284,7 +284,7 @@ install-html: html
>  ../GIT-VERSION-FILE: FORCE
>  	$(QUIET_SUBDIR0)../ $(QUIET_SUBDIR1) GIT-VERSION-FILE
>  
> -ifneq ($(MAKECMDGOALS),clean)
> +ifneq ($(filter-out lint-docs clean,$(MAKECMDGOALS)),)
>  -include ../GIT-VERSION-FILE
>  endif

Re: [PATCH 4/4] doc lint: make "lint-docs" non-.PHONY

[Bagas Sanjaya]

On 15/10/21 19.39, Ævar Arnfjörð Bjarmason wrote:
> @@ -343,6 +348,7 @@ GIT-ASCIIDOCFLAGS: FORCE
>               fi
>   
>   clean:
> +	$(RM) -rf .build/
>   	$(RM) *.xml *.xml+ *.html *.html+ *.1 *.5 *.7
>   	$(RM) *.texi *.texi+ *.texi++ git.info gitman.info
>   	$(RM) *.pdf

Why did you clean the build directory?

-- 
An old man doll... just what I always wanted! - Clara

Re: [PATCH 4/4] doc lint: make "lint-docs" non-.PHONY

[Ævar Arnfjörð Bjarmason]

On Sat, Oct 16 2021, Bagas Sanjaya wrote:

> On 15/10/21 19.39, Ævar Arnfjörð Bjarmason wrote:
>> @@ -343,6 +348,7 @@ GIT-ASCIIDOCFLAGS: FORCE
>>               fi
>>     clean:
>> +	$(RM) -rf .build/
>>   	$(RM) *.xml *.xml+ *.html *.html+ *.1 *.5 *.7
>>   	$(RM) *.texi *.texi+ *.texi++ git.info gitman.info
>>   	$(RM) *.pdf
>
> Why did you clean the build directory?

The Documentation/.build directory is added by this patch, for the lint
scratch files, but the structure is such that it can be used by other
things in the future.