Re: [PATCH 1/1 v2] pager: move pager-specific setup into the build

Originally-from:
 https://public-inbox.org/git/xmqq61piw4yf.fsf@gitster.dls.corp.google.com/

Signed-off-by: Eric Wong <redacted>
---
 Makefile         | 20 +++++++++++++++++++-
 config.mak.uname |  1 +
 git-sh-setup.sh  |  8 +++++---
 pager.c          | 29 +++++++++++++++++++++++++----
 4 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/Makefile b/Makefile
index 6a13386..0b36b5e 100644
--- a/Makefile
+++ b/Makefile

@@ -370,6 +370,14 @@ all::
 # Define HAVE_BSD_SYSCTL if your platform has a BSD-compatible sysctl function.
 #
 # Define HAVE_GETDELIM if your system has the getdelim() function.
+#
+# Define PAGER_ENV to a SP separated VAR=VAL pairs to define
+# default environment variables to be passed when a pager is spawned, e.g.
+#
+#    PAGER_ENV = LESS=FRX LV=-c
+#
+# to say "export LESS=FRX (and LV=-c) if the environment variable
+# LESS (and LV) is not set, respectively".
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN

@@ -1500,6 +1508,10 @@ ifeq ($(PYTHON_PATH),)
 NO_PYTHON = NoThanks
 endif
 
+ifndef PAGER_ENV
+PAGER_ENV = LESS=FRX LV=-c
+endif
+
 QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
 QUIET_SUBDIR1  =
 

@@ -1629,6 +1641,10 @@ ifdef DEFAULT_HELP_FORMAT
 BASIC_CFLAGS += -DDEFAULT_HELP_FORMAT='"$(DEFAULT_HELP_FORMAT)"'
 endif
 
+PAGER_ENV_CQ = "$(subst ",\",$(subst \,\\,$(PAGER_ENV)))"
+PAGER_ENV_CQ_SQ = $(subst ','\'',$(PAGER_ENV_CQ))
+BASIC_CFLAGS += -DPAGER_ENV='$(PAGER_ENV_CQ_SQ)'
+
 ALL_CFLAGS += $(BASIC_CFLAGS)
 ALL_LDFLAGS += $(BASIC_LDFLAGS)
 

@@ -1753,7 +1769,7 @@ common-cmds.h: $(wildcard Documentation/git-*.txt)
 
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
 	$(localedir_SQ):$(NO_CURL):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\
-	$(gitwebdir_SQ):$(PERL_PATH_SQ):$(SANE_TEXT_GREP)
+	$(gitwebdir_SQ):$(PERL_PATH_SQ):$(SANE_TEXT_GREP):$(PAGER_ENV)
 define cmd_munge_script
 $(RM) $@ $@+ && \
 sed -e '1s|#!.*/sh|#!$(SHELL_PATH_SQ)|' \

@@ -1766,6 +1782,7 @@ sed -e '1s|#!.*/sh|#!$(SHELL_PATH_SQ)|' \
     -e 's|@@GITWEBDIR@@|$(gitwebdir_SQ)|g' \
     -e 's|@@PERL@@|$(PERL_PATH_SQ)|g' \
     -e 's|@@SANE_TEXT_GREP@@|$(SANE_TEXT_GREP)|g' \
+    -e 's|@@PAGER_ENV@@|$(PAGER_ENV_SQ)|g' \
     $@.sh >$@+
 endef
 

@@ -2173,6 +2190,7 @@ GIT-BUILD-OPTIONS: FORCE
 	@echo NO_PERL=\''$(subst ','\'',$(subst ','\'',$(NO_PERL)))'\' >>$@+
 	@echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@+
 	@echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@+
+	@echo PAGER_ENV=\''$(subst ','\'',$(subst ','\'',$(PAGER_ENV)))'\' >>$@+
 ifdef TEST_OUTPUT_DIRECTORY
 	@echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@+
 endif

diff --git a/config.mak.uname b/config.mak.uname
index 17fed2f..2484dfb 100644
--- a/config.mak.uname
+++ b/config.mak.uname

@@ -209,6 +209,7 @@ ifeq ($(uname_S),FreeBSD)
 	HAVE_PATHS_H = YesPlease
 	GMTIME_UNRELIABLE_ERRORS = UnfortunatelyYes
 	HAVE_BSD_SYSCTL = YesPlease
+	PAGER_ENV = LESS=FRX LV=-c MORE=-R
 endif
 ifeq ($(uname_S),OpenBSD)
 	NO_STRCASESTR = YesPlease

diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 0c34aa6..0f5a56f 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh

@@ -163,9 +163,11 @@ git_pager() {
 	else
 		GIT_PAGER=cat
 	fi
-	: "${LESS=-FRX}"
-	: "${LV=-c}"
-	export LESS LV
+	for vardef in @@PAGER_ENV@@
+	do
+		var=${vardef%%=*}
+		eval ": \${$vardef} && export $var"
+	done
 
 	eval "$GIT_PAGER" '"$@"'
 }

diff --git a/pager.c b/pager.c
index 4bc0481..cd1ac54 100644
--- a/pager.c
+++ b/pager.c

@@ -63,14 +63,35 @@ const char *git_pager(int stdout_is_tty)
 	return pager;
 }
 
+static void setup_pager_env(struct argv_array *env)
+{
+	const char *pager_env = PAGER_ENV;
+
+	while (*pager_env) {
+		struct strbuf buf = STRBUF_INIT;
+		const char *cp = strchrnul(pager_env, '=');
+
+		if (!*cp)
+			die("malformed build-time PAGER_ENV");
+		strbuf_add(&buf, pager_env, cp - pager_env);
+		cp = strchrnul(pager_env, ' ');
+		if (!getenv(buf.buf)) {
+			strbuf_reset(&buf);
+			strbuf_add(&buf, pager_env, cp - pager_env);
+			argv_array_push(env, strbuf_detach(&buf, NULL));
+		}
+		strbuf_reset(&buf);
+		while (*cp && *cp == ' ')
+			cp++;
+		pager_env = cp;
+	}
+}
+
 void prepare_pager_args(struct child_process *pager_process, const char *pager)
 {
 	argv_array_push(&pager_process->args, pager);
 	pager_process->use_shell = 1;
-	if (!getenv("LESS"))
-		argv_array_push(&pager_process->env_array, "LESS=FRX");
-	if (!getenv("LV"))
-		argv_array_push(&pager_process->env_array, "LV=-c");
+	setup_pager_env(&pager_process->env_array);
 }
 
 void setup_pager(void)