[PATCH 1/3] chainlint: sidestep impoverished macOS "terminfo"

From: Eric Sunshine via GitGitGadget <gitgitgadget@gmail.com>
Date: Nov 9, 2022, 16:58 UTC
Message-ID: <b85b28e5a6beea97c149f0b9de6ba8d0a4a7c1f9.1668013114.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.1413.git.1668013114.gitgitgadget@gmail.com>

From: Eric Sunshine <sunshine@sunshineco.com>

Although the macOS Terminal.app is "xterm"-compatible, its corresponding "terminfo" entry neglects to mention capabilities which Terminal.app actually supports (such as "dim text"). This oversight on Apple's part ends up penalizing users of "good citizen" console programs which consult "terminfo" to tailor their output based upon reported terminal capabilities (as opposed to programs which assume that the terminal supports ANSI codes).

Sidestep this Apple problem by imbuing get_colors() with specific knowledge of "xterm" capabilities rather than trusting "terminfo" to report them correctly. Although hard-coding such knowledge is ugly, "xterm" support is nearly ubiquitous these days, and Git itself sets precedence by assuming support for ANSI color codes. For non-"xterm", fall back to querying "terminfo" via `tput` as usual.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
---
 t/chainlint.pl | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/t/chainlint.pl b/t/chainlint.pl
index 7972c5bbe6f..fcf4d459249 100755
--- a/t/chainlint.pl
+++ b/t/chainlint.pl
@@ -653,21 +653,32 @@ my @NOCOLORS = (bold => '', rev => '', reset => '', blue => '', green => '', red
 my %COLORS = ();
 sub get_colors {
 	return \%COLORS if %COLORS;
-	if (exists($ENV{NO_COLOR}) ||
-	    system("tput sgr0 >/dev/null 2>&1") != 0 ||
-	    system("tput bold >/dev/null 2>&1") != 0 ||
-	    system("tput rev  >/dev/null 2>&1") != 0 ||
-	    system("tput setaf 1 >/dev/null 2>&1") != 0) {
+	if (exists($ENV{NO_COLOR})) {
 		%COLORS = @NOCOLORS;
 		return \%COLORS;
 	}
-	%COLORS = (bold  => `tput bold`,
-		   rev   => `tput rev`,
-		   reset => `tput sgr0`,
-		   blue  => `tput setaf 4`,
-		   green => `tput setaf 2`,
-		   red   => `tput setaf 1`);
-	chomp(%COLORS);
+	if ($ENV{TERM} =~ /\bxterm\b/) {
+		%COLORS = (bold  => "\e[1m",
+			   rev   => "\e[7m",
+			   reset => "\e[0m",
+			   blue  => "\e[34m",
+			   green => "\e[32m",
+			   red   => "\e[31m");
+		return \%COLORS;
+	}
+	if (system("tput sgr0 >/dev/null 2>&1") == 0 &&
+	    system("tput bold >/dev/null 2>&1") == 0 &&
+	    system("tput rev  >/dev/null 2>&1") == 0 &&
+	    system("tput setaf 1 >/dev/null 2>&1") == 0) {
+		%COLORS = (bold  => `tput bold`,
+			   rev   => `tput rev`,
+			   reset => `tput sgr0`,
+			   blue  => `tput setaf 4`,
+			   green => `tput setaf 2`,
+			   red   => `tput setaf 1`);
+		return \%COLORS;
+	}
+	%COLORS = @NOCOLORS;
 	return \%COLORS;
 }

-- 
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