From 5b2f02d826d8043b6b89860c56802ea5fed0f3bd Mon Sep 17 00:00:00 2001
From: Craig Barnes <craigbarnes@protonmail.com>
Date: Mon, 20 Mar 2023 14:40:36 +0000
Subject: [PATCH] slave: set $TERM_PROGRAM and $TERM_PROGRAM_VERSION
 environment variables

These are already being set by iTerm2, WezTerm, tmux and likely some
others. Even though using yet more environment variables seems rather
questionable, if we don't set these we run the risk of inheriting them
from other terminals.

See also:

* https://gitlab.com/gnachman/iterm2/-/blob/97a6078df8e822da165e91737a01c0b9e115dd16/sources/PTYSession.m#L2568-2570
* https://github.com/tmux/tmux/blob/1d0f68dee9f71c504e03616fa472a408a6caa49b/environ.c#L263-L264
* https://github.com/search?q=TERM_PROGRAM&type=code
---
 CHANGELOG.md         |  2 ++
 doc/foot.1.scd       | 11 +++++++++++
 doc/footclient.1.scd | 11 +++++++++++
 generate-version.sh  |  1 +
 slave.c              |  3 +++
 5 files changed, 28 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 08d7d69f..01d664fc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -61,6 +61,8 @@
 * “Report version” terminfo entries (`XR`/`xr`).
 * “Report DA2” terminfo entries (`RV`/`rv`).
 * `XF` terminfo capability (focus in/out events available).
+* `$TERM_PROGRAM` and `$TERM_PROGRAM_VERSION` environment variables
+  set in the slave process.
 
 [1136]: https://codeberg.org/dnkl/foot/issues/1136
 [1225]: https://codeberg.org/dnkl/foot/issues/1225
diff --git a/doc/foot.1.scd b/doc/foot.1.scd
index 6f63d4c8..51c53130 100644
--- a/doc/foot.1.scd
+++ b/doc/foot.1.scd
@@ -546,6 +546,17 @@ In all other cases, the exit code is that of the client application
 	This variable is set to *truecolor*, to indicate to client
 	applications that 24-bit RGB colors are supported.
 
+*TERM_PROGRAM*
+	Always set to *foot*. This can be used by client applications to
+	check which terminal is in use, but with the caveat that it may
+	have been inherited from a parent process in other terminals that
+	aren't known to set the variable.
+
+*TERM_PROGRAM_VERSION*
+	Set to the foot version string, in the format _major_*.*_minor_*.*_patch_
+	or _major_*.*_minor_*.*_patch_*-*_revision_*-\g*_commit_ for inter-release
+	builds. The same caveat as for *TERM_PROGRAM* applies.
+
 In addition to the variables listed above, custom environment
 variables may be defined in *foot.ini*(5).
 
diff --git a/doc/footclient.1.scd b/doc/footclient.1.scd
index 63235134..189d9e3c 100644
--- a/doc/footclient.1.scd
+++ b/doc/footclient.1.scd
@@ -158,6 +158,17 @@ terminfo entries manually, by copying *foot* and *foot-direct* to
 	This variable is set to *truecolor*, to indicate to client
 	applications that 24-bit RGB colors are supported.
 
+*TERM_PROGRAM*
+	Always set to *foot*. This can be used by client applications to
+	check which terminal is in use, but with the caveat that it may
+	have been inherited from a parent process in other terminals that
+	aren't known to set the variable.
+
+*TERM_PROGRAM_VERSION*
+	Set to the foot version string, in the format _major_*.*_minor_*.*_patch_
+	or _major_*.*_minor_*.*_patch_*-*_revision_*-\g*_commit_ for inter-release
+	builds. The same caveat as for *TERM_PROGRAM* applies.
+
 In addition to the variables listed above, custom environment
 variables may be defined in *foot.ini*(5).
 
diff --git a/generate-version.sh b/generate-version.sh
index a030d512..3772008b 100755
--- a/generate-version.sh
+++ b/generate-version.sh
@@ -41,6 +41,7 @@ patch=$(echo "${new_version}" | sed -r 's/([0-9]+)\.([0-9]+)\.([0-9]+).*/\3/')
 extra=$(echo "${new_version}" | sed -r 's/([0-9]+)\.([0-9]+)\.([0-9]+)(-([0-9]+-g[a-z0-9]+) .*)?.*/\5/')
 
 new_version="#define FOOT_VERSION \"${new_version}\"
+#define FOOT_VERSION_SHORT \"${git_version:-${default_version}}\"
 #define FOOT_MAJOR ${major}
 #define FOOT_MINOR ${minor}
 #define FOOT_PATCH ${patch}
diff --git a/slave.c b/slave.c
index d4861ad0..2f23e996 100644
--- a/slave.c
+++ b/slave.c
@@ -21,6 +21,7 @@
 #include "macros.h"
 #include "terminal.h"
 #include "tokenize.h"
+#include "version.h"
 #include "xmalloc.h"
 
 extern char **environ;
@@ -351,6 +352,8 @@ slave_spawn(int ptmx, int argc, const char *cwd, char *const *argv,
         }
 
         setenv("TERM", term_env, 1);
+        setenv("TERM_PROGRAM", "foot", 1);
+        setenv("TERM_PROGRAM_VERSION", FOOT_VERSION_SHORT, 1);
         setenv("COLORTERM", "truecolor", 1);
         setenv("PWD", cwd, 1);