trace2: rename environment variables to GIT_TRACE2*

For an environment variable that is supposed to be set by users, the
GIT_TR2* env vars are just too unclear, inconsistent, and ugly.

Most of the established GIT_* environment variables don't use
abbreviations, and in case of the few that do (GIT_DIR,
GIT_COMMON_DIR, GIT_DIFF_OPTS) it's quite obvious what the
abbreviations (DIR and OPTS) stand for.  But what does TR stand for?
Track, traditional, trailer, transaction, transfer, transformation,
transition, translation, transplant, transport, traversal, tree,
trigger, truncate, trust, or ...?!

The trace2 facility, as the '2' suffix in its name suggests, is
supposed to eventually supercede Git's original trace facility.  It's
reasonable to expect that the corresponding environment variables
follow suit, and after the original GIT_TRACE variables they are
called GIT_TRACE2; there is no such thing is 'GIT_TR'.

All trace2-specific config variables are, very sensibly, in the
'trace2' section, not in 'tr2'.

OTOH, we don't gain anything at all by omitting the last three
characters of "trace" from the names of these environment variables.

So let's rename all GIT_TR2* environment variables to GIT_TRACE2*,
before they make their way into a stable release.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 13 insertions, 13 deletions

diff --git a/trace2/tr2_cmd_name.c b/trace2/tr2_cmd_name.c
index e999592b4c..dd313204f5 100644
--- a/trace2/tr2_cmd_name.c
+++ b/trace2/tr2_cmd_name.c
@@ -1,7 +1,7 @@
 #include "cache.h"
 #include "trace2/tr2_cmd_name.h"
 
-#define TR2_ENVVAR_PARENT_NAME "GIT_TR2_PARENT_NAME"
+#define TR2_ENVVAR_PARENT_NAME "GIT_TRACE2_PARENT_NAME"
 
 static struct strbuf tr2cmdname_hierarchy = STRBUF_INIT;
 
diff --git a/trace2/tr2_sid.c b/trace2/tr2_sid.c
index 5047095478..6948fd4108 100644
--- a/trace2/tr2_sid.c
+++ b/trace2/tr2_sid.c
@@ -2,7 +2,7 @@
 #include "trace2/tr2_tbuf.h"
 #include "trace2/tr2_sid.h"
 
-#define TR2_ENVVAR_PARENT_SID "GIT_TR2_PARENT_SID"
+#define TR2_ENVVAR_PARENT_SID "GIT_TRACE2_PARENT_SID"
 
 static struct strbuf tr2sid_buf = STRBUF_INIT;
 static int tr2sid_nr_git_parents;
diff --git a/trace2/tr2_sysenv.c b/trace2/tr2_sysenv.c
index 9025b86303..5958cfc424 100644
--- a/trace2/tr2_sysenv.c
+++ b/trace2/tr2_sysenv.c
@@ -21,33 +21,33 @@ struct tr2_sysenv_entry {
  * The strings in this table are constant and must match the published
  * config and environment variable names as described in the documentation.
  *
- * We do not define entries for the GIT_TR2_PARENT_* environment
+ * We do not define entries for the GIT_TRACE2_PARENT_* environment
  * variables because they are transient and used to pass information
  * from parent to child git processes, rather than settings.
  */
 /* clang-format off */
 static struct tr2_sysenv_entry tr2_sysenv_settings[] = {
-	[TR2_SYSENV_CFG_PARAM]     = { "GIT_TR2_CONFIG_PARAMS",
+	[TR2_SYSENV_CFG_PARAM]     = { "GIT_TRACE2_CONFIG_PARAMS",
 				       "trace2.configparams" },
 
-	[TR2_SYSENV_DST_DEBUG]     = { "GIT_TR2_DST_DEBUG",
+	[TR2_SYSENV_DST_DEBUG]     = { "GIT_TRACE2_DST_DEBUG",
 				       "trace2.destinationdebug" },
 
-	[TR2_SYSENV_NORMAL]        = { "GIT_TR2",
+	[TR2_SYSENV_NORMAL]        = { "GIT_TRACE2",
 				       "trace2.normaltarget" },
-	[TR2_SYSENV_NORMAL_BRIEF]  = { "GIT_TR2_BRIEF",
+	[TR2_SYSENV_NORMAL_BRIEF]  = { "GIT_TRACE2_BRIEF",
 				       "trace2.normalbrief" },
 
-	[TR2_SYSENV_EVENT]         = { "GIT_TR2_EVENT",
+	[TR2_SYSENV_EVENT]         = { "GIT_TRACE2_EVENT",
 				       "trace2.eventtarget" },
-	[TR2_SYSENV_EVENT_BRIEF]   = { "GIT_TR2_EVENT_BRIEF",
+	[TR2_SYSENV_EVENT_BRIEF]   = { "GIT_TRACE2_EVENT_BRIEF",
 				       "trace2.eventbrief" },
-	[TR2_SYSENV_EVENT_NESTING] = { "GIT_TR2_EVENT_NESTING",
+	[TR2_SYSENV_EVENT_NESTING] = { "GIT_TRACE2_EVENT_NESTING",
 				       "trace2.eventnesting" },
 
-	[TR2_SYSENV_PERF]          = { "GIT_TR2_PERF",
+	[TR2_SYSENV_PERF]          = { "GIT_TRACE2_PERF",
 				       "trace2.perftarget" },
-	[TR2_SYSENV_PERF_BRIEF]    = { "GIT_TR2_PERF_BRIEF",
+	[TR2_SYSENV_PERF_BRIEF]    = { "GIT_TRACE2_PERF_BRIEF",
 				       "trace2.perfbrief" },
 };
 /* clang-format on */
diff --git a/trace2/tr2_sysenv.h b/trace2/tr2_sysenv.h
index 369b20bd87..8dd82a7a56 100644
--- a/trace2/tr2_sysenv.h
+++ b/trace2/tr2_sysenv.h
@@ -7,7 +7,7 @@
  *
  * Note that this set does not contain any of the transient
  * environment variables used to pass information from parent
- * to child git processes, such "GIT_TR2_PARENT_SID".
+ * to child git processes, such "GIT_TRACE2_PARENT_SID".
  */
 enum tr2_sysenv_variable {
 	TR2_SYSENV_CFG_PARAM = 0,