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[PATCH 11/16] pager: handle early config

From
Jeff King <peff@peff.net>
Date
Sep 13, 2016, 03:23 UTC
Message-ID
<20160913032356.mj6q5qv6kllbcdfb@sigill.intra.peff.net>
In-Reply-To
<20160913032242.coyuhyhn6uklewuk@sigill.intra.peff.net>

The pager code is often run early in the git.c startup, before we have actually found the repository. When we ask git_config() to look for values like core.pager, it doesn't know where to find the repo-level config, and will blindly examine ".git/config" if it exists. That's why t7006 shows that many pager-related features happen to work from the top-level of a repository, but not from a subdirectory.

This patch pulls that ".git/config" hack explicitly into the pager code. There are two reasons for this:

  1. We'd like to clean up the git_config() behavior, as
     looking at ".git/config" when we do not have a
     configured repository is often the wrong thing to do.
     But we'd prefer not to break the pager config any worse
     than it already is.
  2. It's one very tiny step on the road to ultimately
     making the pager config work consistently. If we
     eventually get an equivalent of setup_git_directory()
     that _just_ finds the directory and doesn't chdir() or
     set up any global state, we could plug it in here
     (instead of blindly looking at ".git/config").
Signed-off-by: Jeff King <peff@peff.net>
---
 pager.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)
diff --git a/pager.c b/pager.c
index 46cc411..ae79643 100644
--- a/pager.c
+++ b/pager.c
@@ -43,6 +43,37 @@ static int core_pager_config(const char *var, const char *value, void *data)
 	return 0;
 }
 
+static void read_early_config(config_fn_t cb, void *data)
+{
+	git_config_with_options(cb, data, NULL, 1);
+
+	/*
+	 * Note that this is a really dirty hack that does the wrong thing in
+	 * many cases. The crux of the problem is that we cannot run
+	 * setup_git_directory() early on in git's setup, so we have no idea if
+	 * we are in a repository or not, and therefore are not sure whether
+	 * and how to read repository-local config.
+	 *
+	 * So if we _aren't_ in a repository (or we are but we would reject its
+	 * core.repositoryformatversion), we'll read whatever is in .git/config
+	 * blindly. Similarly, if we _are_ in a repository, but not at the
+	 * root, we'll fail to find .git/config (because it's really
+	 * ../.git/config, etc). See t7006 for a complete set of failures.
+	 *
+	 * However, we have historically provided this hack because it does
+	 * work some of the time (namely when you are at the top-level of a
+	 * valid repository), and would rarely make things worse (i.e., you do
+	 * not generally have a .git/config file sitting around).
+	 */
+	if (!startup_info->have_repository) {
+		struct git_config_source repo_config;
+
+		memset(&repo_config, 0, sizeof(repo_config));
+		repo_config.file = ".git/config";
+		git_config_with_options(cb, data, &repo_config, 1);
+	}
+}
+
 const char *git_pager(int stdout_is_tty)
 {
 	const char *pager;
@@ -53,7 +84,7 @@ const char *git_pager(int stdout_is_tty)
 	pager = getenv("GIT_PAGER");
 	if (!pager) {
 		if (!pager_program)
-			git_config(core_pager_config, NULL);
+			read_early_config(core_pager_config, NULL);
 		pager = pager_program;
 	}
 	if (!pager)
@@ -216,7 +247,7 @@ int check_pager_config(const char *cmd)
 	data.want = -1;
 	data.value = NULL;
 
-	git_config(pager_command_config, &data);
+	read_early_config(pager_command_config, &data);
 
 	if (data.value)
 		pager_program = data.value;
-- 
2.10.0.230.g6f8d04b
Previous: Jeff KingNext: Jeff King
Message 15 of 23 in “fix config-reading in non-repos”
  1. 0/16 fix config-reading in non-reposJeff King, Sep 13, 2016
  2. 01/16 t1007: factor out repeated setupJeff King, Sep 13, 2016
  3. Stefan BellerSep 13, 2016
  4. 02/16 hash-object: always try to set up the git repositoryJeff King, Sep 13, 2016
  5. 06/16 diff: always try to set up the repositoryJeff King, Sep 13, 2016
  6. Stefan BellerSep 13, 2016
  7. Jeff KingSep 13, 2016
  8. 04/16 diff: skip implicit no-index check when given --no-indexJeff King, Sep 13, 2016
  9. 07/16 pager: remove obsolete commentJeff King, Sep 13, 2016
  10. 03/16 patch-id: use RUN_SETUP_GENTLYJeff King, Sep 13, 2016
  11. 05/16 diff: handle --no-index prefixes consistentlyJeff King, Sep 13, 2016
  12. 08/16 pager: stop loading git_default_config()Jeff King, Sep 13, 2016
  13. 09/16 pager: make pager_program a file-local staticJeff King, Sep 13, 2016
  14. 10/16 pager: use callbacks instead of configsetJeff King, Sep 13, 2016
  15. 11/16 pager: handle early configJeff King, Sep 13, 2016
  16. 12/16 t1302: use "git -C"Jeff King, Sep 13, 2016
  17. 13/16 test-config: setup git directoryJeff King, Sep 13, 2016
  18. 14/16 config: only read .git/config from configured reposJeff King, Sep 13, 2016
  19. 15/16 init: expand comments explaining config trickeryJeff King, Sep 13, 2016
  20. 16/16 init: reset cached config when entering new repoJeff King, Sep 13, 2016
  21. Stefan BellerSep 13, 2016
  22. Dennis KaarsemakerSep 14, 2016
  23. Jeff KingSep 14, 2016

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