[PATCH v3] config: improve error message for boolean config

["Andrew Klotz via GitGitGadget" <gitgitgadget@gmail.com>]

From: Andrew Klotz <agc.klotz@gmail.com>

Currently invalid boolean config values return messages about 'bad
numeric', which is slightly misleading when the error was due to a
boolean value. We can improve the developer experience by returning a
boolean error message when we know the value is neither a bool text or
int.

before with an invalid boolean value of `non-boolean`, its unclear what
numeric is referring to:
  fatal: bad numeric config value 'non-boolean' for 'commit.gpgsign': invalid unit

now the error message mentions `non-boolean` is a bad boolean value:
  fatal: bad boolean config value 'non-boolean' for 'commit.gpgsign'

Signed-off-by: Andrew Klotz <agc.klotz@gmail.com>
---
    config: improve error message for boolean config
    
    Currently invalid boolean config values return messages about 'bad
    numeric', which I found misleading when the error was due to a boolean
    string value. This change makes the error message reflect the boolean
    value.
    
    The current approach relies on GIT_TEST_GETTEXT_POISON being a boolean
    value, moving its special case out from die_bad_number() and into
    git_config_bool_or_int(). An alternative could be for die_bad_number()
    to handle boolean values when erroring, although the function name might
    need to change if it is handling non-numeric values.
    
    changes since v1
    
     * moved boolean error message change out of git_config_bool_or_int to
       just in git_config_bool and added die_bad_boolean instead of
       modifying die_bad_number.
    
    changes since v2
    
     * added a test for boolean config values
     * changed the condition to hit die_bad_bool from if (0 <= v) to if (v <
       0)
     * removed change in get-text-poison.sh test
    
    Signed-off-by: Andrew Klotz agc.klotz@gmail.com

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-841%2FKlotzAndrew%2Fbetter_bool_errors-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-841/KlotzAndrew/better_bool_errors-v3
Pull-Request: https://github.com/git/git/pull/841

Range-diff vs v2:

 1:  32dd4ee1e373 ! 1:  45a51e18c1d3 config: improve error message for boolean config
     @@ Commit message
      
          before with an invalid boolean value of `non-boolean`, its unclear what
          numeric is referring to:
     -    ```
     -    fatal: bad numeric config value 'non-boolean' for 'commit.gpgsign': invalid unit
     -    ```
     +      fatal: bad numeric config value 'non-boolean' for 'commit.gpgsign': invalid unit
      
          now the error message mentions `non-boolean` is a bad boolean value:
     -    ```
     -    fatal: bad boolean config value 'non-boolean' for 'commit.gpgsign'
     -    ```
     +      fatal: bad boolean config value 'non-boolean' for 'commit.gpgsign'
      
          Signed-off-by: Andrew Klotz <agc.klotz@gmail.com>
      
     @@ config.c: int git_config_bool_or_int(const char *name, const char *value, int *i
      -	int discard;
      -	return !!git_config_bool_or_int(name, value, &discard);
      +	int v = git_parse_maybe_bool(value);
     -+	if (0 <= v)
     -+		return v;
     -+	else
     ++	if (v < 0)
      +		die_bad_bool(name, value);
     ++	return v;
       }
       
       int git_config_string(const char **dest, const char *var, const char *value)
      
     - ## t/t0205-gettext-poison.sh ##
     -@@ t/t0205-gettext-poison.sh: test_expect_success 'eval_gettext: our eval_gettext() fallback has poison semant
     - 
     - test_expect_success "gettext: invalid GIT_TEST_GETTEXT_POISON value doesn't infinitely loop" "
     - 	test_must_fail env GIT_TEST_GETTEXT_POISON=xyz git version 2>error &&
     --	grep \"fatal: bad numeric config value 'xyz' for 'GIT_TEST_GETTEXT_POISON': invalid unit\" error
     -+	grep \"fatal: bad boolean config value 'xyz' for 'GIT_TEST_GETTEXT_POISON'\" error
     - "
     + ## t/t1300-config.sh ##
     +@@ t/t1300-config.sh: test_expect_success 'invalid unit' '
     + 	test_i18ngrep "bad numeric config value .1auto. for .aninvalid.unit. in file .git/config: invalid unit" actual
     + '
       
     - test_done
     ++test_expect_success 'invalid unit boolean' '
     ++	git config commit.gpgsign "1true" &&
     ++	test_cmp_config 1true commit.gpgsign &&
     ++	test_must_fail git config --bool --get commit.gpgsign 2>actual &&
     ++	test_i18ngrep "bad boolean config value .1true. for .commit.gpgsign." actual
     ++'
     ++
     + test_expect_success 'line number is reported correctly' '
     + 	printf "[bool]\n\tvar\n" >invalid &&
     + 	test_must_fail git config -f invalid --path bool.var 2>actual &&


 config.c          | 20 ++++++++++++++++++--
 t/t1300-config.sh |  7 +++++++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/config.c b/config.c
index b922b4f28572..f90b633dba21 100644
--- a/config.c
+++ b/config.c
@@ -1180,6 +1180,20 @@ static void die_bad_number(const char *name, const char *value)
 	}
 }
 
+NORETURN
+static void die_bad_bool(const char *name, const char *value)
+{
+	if (!strcmp(name, "GIT_TEST_GETTEXT_POISON"))
+		/*
+		 * We explicitly *don't* use _() here since it would
+		 * cause an infinite loop with _() needing to call
+		 * use_gettext_poison().
+		 */
+		die("bad boolean config value '%s' for '%s'", value, name);
+	else
+		die(_("bad boolean config value '%s' for '%s'"), value, name);
+}
+
 int git_config_int(const char *name, const char *value)
 {
 	int ret;
@@ -1252,8 +1266,10 @@ int git_config_bool_or_int(const char *name, const char *value, int *is_bool)
 
 int git_config_bool(const char *name, const char *value)
 {
-	int discard;
-	return !!git_config_bool_or_int(name, value, &discard);
+	int v = git_parse_maybe_bool(value);
+	if (v < 0)
+		die_bad_bool(name, value);
+	return v;
 }
 
 int git_config_string(const char **dest, const char *var, const char *value)
diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index 936d72041bab..e0dd5d65ceda 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -675,6 +675,13 @@ test_expect_success 'invalid unit' '
 	test_i18ngrep "bad numeric config value .1auto. for .aninvalid.unit. in file .git/config: invalid unit" actual
 '
 
+test_expect_success 'invalid unit boolean' '
+	git config commit.gpgsign "1true" &&
+	test_cmp_config 1true commit.gpgsign &&
+	test_must_fail git config --bool --get commit.gpgsign 2>actual &&
+	test_i18ngrep "bad boolean config value .1true. for .commit.gpgsign." actual
+'
+
 test_expect_success 'line number is reported correctly' '
 	printf "[bool]\n\tvar\n" >invalid &&
 	test_must_fail git config -f invalid --path bool.var 2>actual &&

base-commit: c6102b758572c7515f606b2423dfe38934fe6764
-- 
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