[devel] [PATCH] Introduce nodiff directive for gear-rules

["Vladimir D. Seleznev" <vseleznv@altlinux.org>]

The directive specifies whitespace-separated list of glob patterns that
define files that should be excluded from diff generation.

Signed-off-by: Vladimir D. Seleznev <vseleznv@altlinux.org>
---
 gear            | 24 ++++++++++++++++++------
 gear-rules.5.in | 18 ++++++++++++++++++
 2 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/gear b/gear
index 6282c92..0589b06 100755
--- a/gear
+++ b/gear
@@ -402,13 +402,14 @@ write_git_diff()
 {
 	local optional="$1" && shift
 	local cmd="$1" && shift
+	local nodiff_patterns="$1" && shift
 	local old_tree="$1" && shift
 	local old_dir="$1" && shift
 	local new_tree="$1" && shift
 	local new_dir="$1" && shift
 	local name="${1##*/}" && shift
 
-	local old_id new_id
+	local old_id new_id nodiff=
 
 	old_id="$(traverse_tree "$old_tree" "$old_dir" "$optional")" ||
 		{
@@ -422,8 +423,13 @@ write_git_diff()
 				exit 1
 		}
 
+	for pattern in $nodiff_patterns; do
+		[ -n "$pattern" ] ||continue
+		nodiff="$nodiff $(printf ":^%s" "$pattern")"
+	done
+
 	git diff-tree --patch-with-stat --text --no-renames --no-ext-diff \
-		"$old_id" "$new_id" >"$outdir/$name"
+		"$old_id" "$new_id" $nodiff >"$outdir/$name"
 	verbose "Extracted diff: $name"
 
 	compress_file "$cmd" "$name" ''
@@ -436,6 +442,7 @@ make_difference()
 		rules_error 'No old_dir or new_dir specified'
 	local optional="$1" && shift
 	local cmd="$1" && shift
+	local nodiff_patterns="$1" && shift
 	local old_dir="$1" && shift
 	local new_dir="$1" && shift
 
@@ -456,7 +463,7 @@ make_difference()
 	diff_new_tree="$(resolve_tree_base_name "$diff_new_tree")" ||
 		rules_error "Invalid new tree: $diff_new_tree"
 
-	write_git_diff "$optional" "$cmd" "$diff_old_tree" "$old_dir" "$diff_new_tree" "$new_dir" "$diff_name"
+	write_git_diff "$optional" "$cmd" "$nodiff_patterns" "$diff_old_tree" "$old_dir" "$diff_new_tree" "$new_dir" "$diff_name"
 }
 
 extract_pattern()
@@ -564,7 +571,7 @@ parse_rules()
 	exclude_pattern_list=
 	lineno=0
 
-	local cmd options
+	local cmd options nodiff_patterns=
 	while read -r cmd options; do
 		lineno="$((lineno+1))"
 		if [ "$cmd" = 'exclude:' ]; then
@@ -572,6 +579,11 @@ parse_rules()
 				rules_error "Invalid exclude pattern specified: $options"
 			exclude_pattern_list="$exclude_pattern_list $options"
 		fi
+		if [ "$cmd" = 'nodiff:' ]; then
+			[ -z "$(printf %s "$options" |tr -d '[:alnum:]_.?*-/ ')" ] ||
+				rules_error "Invalid nodiff pattern specified: $options"
+			nodiff_patterns="$nodiff_patterns $options"
+		fi
 	done <"$workdir/rules"
 
 	lineno=0
@@ -601,7 +613,7 @@ parse_rules()
 		eval "set -- $opts"
 
 		case "$cmd" in
-			spec|specsubst|exclude|tags)
+			spec|specsubst|exclude|tags|nodiff)
 				continue
 				;;
 			tar|tar.gz|tar.bz2|tar.lzma|tar.xz|tar.zst)
@@ -613,7 +625,7 @@ parse_rules()
 					rules_error 'Failed to make archive'
 				;;
 			diff|diff.gz|diff.bz2|diff.lzma|diff.xz|diff.zst)
-				make_difference "$optional" "$cmd" "$@" ||
+				make_difference "$optional" "$cmd" "$nodiff_patterns" "$@" ||
 					rules_error 'Failed to make diff'
 				;;
 			copy|gzip|bzip2|lzma|xz|zstd)
diff --git a/gear-rules.5.in b/gear-rules.5.in
index 5469199..c1b6793 100644
--- a/gear-rules.5.in
+++ b/gear-rules.5.in
@@ -452,6 +452,12 @@ or
 .I new_tree_path
 specify non-default base trees, these trees still must be valid.
 .TP
+.BI "nodiff: " glob_pattern...
+Specify whitespace-separated list of glob patterns that define files that
+should be excluded from diff generation. Affects  all  directives  in  the
+rule file irrespective of the order. Specifying a glob pattern which does not
+match any files in the tree is not an error.
+.TP
 .BI "specsubst: " variables...
 Specify whitespace-separated list of variables that should be substituted
 in specfile.  Variable names may contain letters, digits and underscore
@@ -541,6 +547,18 @@ However, if a prerelease version is packaged, parts like
 \*(lqpreN\*(rq or \*(lqrcN\*(rq should not be included in the package
 version, therefore the rule file will need some modifications for such
 versions.
+.PP
+You can also want to exclude
+.BR .gear
+subdirectory and spec file from diff generation:
+.RS 4
+.PP
+.ft CW
+.nf
+nodiff: .gear/** *.spec
+.fi
+.RE
+.PP
 .
 .SS "Archive with unmodified sources and separate patch files"
 If you prefer to maintain patch files for local modifications instead
-- 
2.25.4