[PATCH] builtins + test helpers: use return instead of exit() in cmd_*

Change various cmd_* functions to use "return" instead of exit() to
indicate an exit code. On Solaris with SunCC the compiler legitimately
complains about these, since we'll e.g. skip the cleanup (e.g. closing
fd's, erroring if we can't) in git.c's run_builtin() when we exit()
directly like this.

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---

A trivial issue noticed in my pre-v2.32.0 testing that I wanted to
leave until after the release.

 builtin/difftool.c          | 5 ++---
 builtin/merge-ours.c        | 2 +-
 builtin/mktree.c            | 2 +-
 t/helper/test-hash-speed.c  | 2 +-
 t/helper/test-hash.c        | 2 +-
 t/helper/test-match-trees.c | 2 +-
 t/helper/test-reach.c       | 2 +-
 7 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/builtin/difftool.c b/builtin/difftool.c
index 89334b77fb..6a9242a803 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c

@@ -675,7 +675,7 @@ static int run_file_diff(int prompt, const char *prefix,
 		"GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
 		NULL
 	};
-	int ret = 0, i;
+	int i;
 
 	if (prompt > 0)
 		env[2] = "GIT_DIFFTOOL_PROMPT=true";

@@ -686,8 +686,7 @@ static int run_file_diff(int prompt, const char *prefix,
 	strvec_push(&args, "diff");
 	for (i = 0; i < argc; i++)
 		strvec_push(&args, argv[i]);
-	ret = run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
-	exit(ret);
+	return run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
 }
 
 int cmd_difftool(int argc, const char **argv, const char *prefix)

diff --git a/builtin/merge-ours.c b/builtin/merge-ours.c
index 4594507420..a745c32ae4 100644
--- a/builtin/merge-ours.c
+++ b/builtin/merge-ours.c

@@ -29,5 +29,5 @@ int cmd_merge_ours(int argc, const char **argv, const char *prefix)
 		die_errno("read_cache failed");
 	if (index_differs_from(the_repository, "HEAD", NULL, 0))
 		exit(2);
-	exit(0);
+	return 0;
 }

diff --git a/builtin/mktree.c b/builtin/mktree.c
index 891991b00d..ae78ca1c02 100644
--- a/builtin/mktree.c
+++ b/builtin/mktree.c

@@ -189,5 +189,5 @@ int cmd_mktree(int ac, const char **av, const char *prefix)
 		used=0; /* reset tree entry buffer for re-use in batch mode */
 	}
 	strbuf_release(&sb);
-	exit(0);
+	return 0;
 }

diff --git a/t/helper/test-hash-speed.c b/t/helper/test-hash-speed.c
index 432233c7f0..f40d9ad0c2 100644
--- a/t/helper/test-hash-speed.c
+++ b/t/helper/test-hash-speed.c

@@ -57,5 +57,5 @@ int cmd__hash_speed(int ac, const char **av)
 		free(p);
 	}
 
-	exit(0);
+	return 0;
 }

diff --git a/t/helper/test-hash.c b/t/helper/test-hash.c
index 0a31de66f3..261c545b9d 100644
--- a/t/helper/test-hash.c
+++ b/t/helper/test-hash.c

@@ -54,5 +54,5 @@ int cmd_hash_impl(int ac, const char **av, int algo)
 		fwrite(hash, 1, algop->rawsz, stdout);
 	else
 		puts(hash_to_hex_algop(hash, algop));
-	exit(0);
+	return 0;
 }

diff --git a/t/helper/test-match-trees.c b/t/helper/test-match-trees.c
index b9fd427571..4079fdee06 100644
--- a/t/helper/test-match-trees.c
+++ b/t/helper/test-match-trees.c

@@ -23,5 +23,5 @@ int cmd__match_trees(int ac, const char **av)
 	shift_tree(the_repository, &one->object.oid, &two->object.oid, &shifted, -1);
 	printf("shifted: %s\n", oid_to_hex(&shifted));
 
-	exit(0);
+	return 0;
 }

diff --git a/t/helper/test-reach.c b/t/helper/test-reach.c
index cda804ed79..2f65c7f6a5 100644
--- a/t/helper/test-reach.c
+++ b/t/helper/test-reach.c

@@ -166,5 +166,5 @@ int cmd__reach(int ac, const char **av)
 		print_sorted_commit_ids(list);
 	}
 
-	exit(0);
+	return 0;
 }

-- 
2.32.0.rc3.434.gd8aed1f08a7

Ævar Arnfjörð Bjarmason wrote:

Change various cmd_* functions to use "return" instead of exit() to
indicate an exit code. On Solaris with SunCC the compiler legitimately
complains about these, since we'll e.g. skip the cleanup (e.g. closing
fd's, erroring if we can't) in git.c's run_builtin() when we exit()
directly like this.

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>

Makes sense to me and it's obviously correct.

Reviewed-by: Felipe Contreras <redacted>

-- 
Felipe Contreras

On Mon, Jun 07, 2021 at 01:12:48PM +0200, Ævar Arnfjörð Bjarmason wrote:

Change various cmd_* functions to use "return" instead of exit() to
indicate an exit code. On Solaris with SunCC the compiler legitimately
complains about these, since we'll e.g. skip the cleanup (e.g. closing
fd's, erroring if we can't) in git.c's run_builtin() when we exit()
directly like this.

Each of these cases looks like a simple and obvious conversion, and I
certainly don't mind us doing it.

But I do wonder what SunCC is complaining about exactly. Calling exit()
means you don't have to worry about cleanup anymore. Does the compiler
not have any notion of NORETURN or equivalent? If so, I'd expect many
more complaints in general that we probably _won't_ want to silence,
because it will be awkward to do so.

This one I'm not surprised that a compiler would complain about. The
function returns an int, but there are no return paths from the
function (and hence the caller doing "return run_diff_files()" likewise
could not ever return there. Which is not quite what you said it
complained about above, hence my curiosity. :)

-Peff

Change various cmd_* functions that claim no return an "int" to use
"return" instead of exit() to indicate an exit code. These were not
marked with NORETURN, and by directly exit()-ing we'll skip the
cleanup git.c would otherwise do (e.g. closing fd's, erroring if we
can't). See run_builtin() in git.c.

In the case of shell.c and sh-i18n--envsubst.c this was the result of
an incomplete migration to using a cmd_main() in 3f2e2297b9 (add an
extra level of indirection to main(), 2016-07-01).

This was spotted by SunCC 12.5 on Solaris 10 (gcc210 on the gccfarm).

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---

Clarified the commit message, and made the same s/exit/return/g change
in shell.c and sh-i18n--envsubst.c. I also missed an "exit(2)" in a
brach in builtin/merge-ours.c.

Range-diff against v1:
1:  61d7e6e079 ! 1:  f225b78e01 builtins + test helpers: use return instead of exit() in cmd_*
    @@ Metadata
      ## Commit message ##
         builtins + test helpers: use return instead of exit() in cmd_*
     
    -    Change various cmd_* functions to use "return" instead of exit() to
    -    indicate an exit code. On Solaris with SunCC the compiler legitimately
    -    complains about these, since we'll e.g. skip the cleanup (e.g. closing
    -    fd's, erroring if we can't) in git.c's run_builtin() when we exit()
    -    directly like this.
    +    Change various cmd_* functions that claim no return an "int" to use
    +    "return" instead of exit() to indicate an exit code. These were not
    +    marked with NORETURN, and by directly exit()-ing we'll skip the
    +    cleanup git.c would otherwise do (e.g. closing fd's, erroring if we
    +    can't). See run_builtin() in git.c.
    +
    +    In the case of shell.c and sh-i18n--envsubst.c this was the result of
    +    an incomplete migration to using a cmd_main() in 3f2e2297b9 (add an
    +    extra level of indirection to main(), 2016-07-01).
    +
    +    This was spotted by SunCC 12.5 on Solaris 10 (gcc210 on the gccfarm).
     
         Signed-off-by: Ævar Arnfjörð Bjarmason [off-list ref]
     
    @@ builtin/difftool.c: static int run_file_diff(int prompt, const char *prefix,
     
      ## builtin/merge-ours.c ##
     @@ builtin/merge-ours.c: int cmd_merge_ours(int argc, const char **argv, const char *prefix)
    + 	if (read_cache() < 0)
      		die_errno("read_cache failed");
      	if (index_differs_from(the_repository, "HEAD", NULL, 0))
    - 		exit(2);
    +-		exit(2);
     -	exit(0);
    ++		return 2;
     +	return 0;
      }
     
    @@ builtin/mktree.c: int cmd_mktree(int ac, const char **av, const char *prefix)
     +	return 0;
      }
     
    + ## sh-i18n--envsubst.c ##
    +@@ sh-i18n--envsubst.c: cmd_main (int argc, const char *argv[])
    +   if (ferror (stderr) || fflush (stderr))
    +     {
    +       fclose (stderr);
    +-      exit (EXIT_FAILURE);
    ++      return (EXIT_FAILURE);
    +     }
    +   if (fclose (stderr) && errno != EBADF)
    +-    exit (EXIT_FAILURE);
    ++    return (EXIT_FAILURE);
    + 
    +-  exit (EXIT_SUCCESS);
    ++  return (EXIT_SUCCESS);
    + }
    + 
    + /* Parse the string and invoke the callback each time a $VARIABLE or
    +
    + ## shell.c ##
    +@@ shell.c: int cmd_main(int argc, const char **argv)
    + 		default:
    + 			continue;
    + 		}
    +-		exit(cmd->exec(cmd->name, arg));
    ++		return cmd->exec(cmd->name, arg);
    + 	}
    + 
    + 	cd_to_homedir();
    +
      ## t/helper/test-hash-speed.c ##
     @@ t/helper/test-hash-speed.c: int cmd__hash_speed(int ac, const char **av)
      		free(p);

 builtin/difftool.c          | 5 ++---
 builtin/merge-ours.c        | 4 ++--
 builtin/mktree.c            | 2 +-
 sh-i18n--envsubst.c         | 6 +++---
 shell.c                     | 2 +-
 t/helper/test-hash-speed.c  | 2 +-
 t/helper/test-hash.c        | 2 +-
 t/helper/test-match-trees.c | 2 +-
 t/helper/test-reach.c       | 2 +-
 9 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/builtin/difftool.c b/builtin/difftool.c
index 89334b77fb..6a9242a803 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c

@@ -675,7 +675,7 @@ static int run_file_diff(int prompt, const char *prefix,
 		"GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
 		NULL
 	};
-	int ret = 0, i;
+	int i;
 
 	if (prompt > 0)
 		env[2] = "GIT_DIFFTOOL_PROMPT=true";

@@ -686,8 +686,7 @@ static int run_file_diff(int prompt, const char *prefix,
 	strvec_push(&args, "diff");
 	for (i = 0; i < argc; i++)
 		strvec_push(&args, argv[i]);
-	ret = run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
-	exit(ret);
+	return run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
 }
 
 int cmd_difftool(int argc, const char **argv, const char *prefix)

diff --git a/builtin/merge-ours.c b/builtin/merge-ours.c
index 4594507420..3583cff71c 100644
--- a/builtin/merge-ours.c
+++ b/builtin/merge-ours.c

@@ -28,6 +28,6 @@ int cmd_merge_ours(int argc, const char **argv, const char *prefix)
 	if (read_cache() < 0)
 		die_errno("read_cache failed");
 	if (index_differs_from(the_repository, "HEAD", NULL, 0))
-		exit(2);
-	exit(0);
+		return 2;
+	return 0;
 }

diff --git a/builtin/mktree.c b/builtin/mktree.c
index 891991b00d..ae78ca1c02 100644
--- a/builtin/mktree.c
+++ b/builtin/mktree.c

@@ -189,5 +189,5 @@ int cmd_mktree(int ac, const char **av, const char *prefix)
 		used=0; /* reset tree entry buffer for re-use in batch mode */
 	}
 	strbuf_release(&sb);
-	exit(0);
+	return 0;
 }

diff --git a/sh-i18n--envsubst.c b/sh-i18n--envsubst.c
index e7430b9aa8..6cd307ac2c 100644
--- a/sh-i18n--envsubst.c
+++ b/sh-i18n--envsubst.c

@@ -104,12 +104,12 @@ cmd_main (int argc, const char *argv[])
   if (ferror (stderr) || fflush (stderr))
     {
       fclose (stderr);
-      exit (EXIT_FAILURE);
+      return (EXIT_FAILURE);
     }
   if (fclose (stderr) && errno != EBADF)
-    exit (EXIT_FAILURE);
+    return (EXIT_FAILURE);
 
-  exit (EXIT_SUCCESS);
+  return (EXIT_SUCCESS);
 }
 
 /* Parse the string and invoke the callback each time a $VARIABLE or

diff --git a/shell.c b/shell.c
index cef7ffdc9e..811e13b9c9 100644
--- a/shell.c
+++ b/shell.c

@@ -177,7 +177,7 @@ int cmd_main(int argc, const char **argv)
 		default:
 			continue;
 		}
-		exit(cmd->exec(cmd->name, arg));
+		return cmd->exec(cmd->name, arg);
 	}
 
 	cd_to_homedir();

diff --git a/t/helper/test-hash-speed.c b/t/helper/test-hash-speed.c
index 432233c7f0..f40d9ad0c2 100644
--- a/t/helper/test-hash-speed.c
+++ b/t/helper/test-hash-speed.c

@@ -57,5 +57,5 @@ int cmd__hash_speed(int ac, const char **av)
 		free(p);
 	}
 
-	exit(0);
+	return 0;
 }

diff --git a/t/helper/test-hash.c b/t/helper/test-hash.c
index 0a31de66f3..261c545b9d 100644
--- a/t/helper/test-hash.c
+++ b/t/helper/test-hash.c

@@ -54,5 +54,5 @@ int cmd_hash_impl(int ac, const char **av, int algo)
 		fwrite(hash, 1, algop->rawsz, stdout);
 	else
 		puts(hash_to_hex_algop(hash, algop));
-	exit(0);
+	return 0;
 }

diff --git a/t/helper/test-match-trees.c b/t/helper/test-match-trees.c
index b9fd427571..4079fdee06 100644
--- a/t/helper/test-match-trees.c
+++ b/t/helper/test-match-trees.c

@@ -23,5 +23,5 @@ int cmd__match_trees(int ac, const char **av)
 	shift_tree(the_repository, &one->object.oid, &two->object.oid, &shifted, -1);
 	printf("shifted: %s\n", oid_to_hex(&shifted));
 
-	exit(0);
+	return 0;
 }

diff --git a/t/helper/test-reach.c b/t/helper/test-reach.c
index cda804ed79..2f65c7f6a5 100644
--- a/t/helper/test-reach.c
+++ b/t/helper/test-reach.c

@@ -166,5 +166,5 @@ int cmd__reach(int ac, const char **av)
 		print_sorted_commit_ids(list);
 	}
 
-	exit(0);
+	return 0;
 }

-- 
2.32.0.rc3.434.gd8aed1f08a7

On Tue, Jun 08 2021, Jeff King wrote:

On Mon, Jun 07, 2021 at 01:12:48PM +0200, Ævar Arnfjörð Bjarmason wrote:

quoted

Change various cmd_* functions to use "return" instead of exit() to
indicate an exit code. On Solaris with SunCC the compiler legitimately
complains about these, since we'll e.g. skip the cleanup (e.g. closing
fd's, erroring if we can't) in git.c's run_builtin() when we exit()
directly like this.

Each of these cases looks like a simple and obvious conversion, and I
certainly don't mind us doing it.

But I do wonder what SunCC is complaining about exactly. Calling exit()
means you don't have to worry about cleanup anymore. Does the compiler
not have any notion of NORETURN or equivalent? If so, I'd expect many
more complaints in general that we probably _won't_ want to silence,
because it will be awkward to do so.

It does, but in this case there's no NORETURN and we declared the
command to return int, and it's not the "main" function.

I believe that's what trips it up, as noted in a v2 I just submitted
now:
https://lore.kernel.org/git/patch-1.1-f225b78e01-20210608T104454Z-avarab@gmail.com/

It's not whining about every instance of "exit" in the codebase.

quoted

diff --git a/builtin/difftool.c b/builtin/difftool.c
index 89334b77fb..6a9242a803 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c

@@ -675,7 +675,7 @@ static int run_file_diff(int prompt, const char *prefix,
 		"GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
 		NULL
 	};
-	int ret = 0, i;
+	int i;
 
 	if (prompt > 0)
 		env[2] = "GIT_DIFFTOOL_PROMPT=true";

@@ -686,8 +686,7 @@ static int run_file_diff(int prompt, const char *prefix,
 	strvec_push(&args, "diff");
 	for (i = 0; i < argc; i++)
 		strvec_push(&args, argv[i]);
-	ret = run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
-	exit(ret);
+	return run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
 }

This one I'm not surprised that a compiler would complain about. The
function returns an int, but there are no return paths from the
function (and hence the caller doing "return run_diff_files()" likewise
could not ever return there. Which is not quite what you said it
complained about above, hence my curiosity. :)

I sent a few miscellaneous fixes recently for 15-20 SunCC
warnings. Around 1/2 of these are legitimate issues like these, the rest
are bugs in SunCC or flaws in it flow analysis or other known bugs in
the compiler.

On 08/06/2021 07:49, Jeff King wrote:

On Mon, Jun 07, 2021 at 01:12:48PM +0200, Ævar Arnfjörð Bjarmason wrote:

quoted

Change various cmd_* functions to use "return" instead of exit() to
indicate an exit code. On Solaris with SunCC the compiler legitimately
complains about these, since we'll e.g. skip the cleanup (e.g. closing
fd's, erroring if we can't) in git.c's run_builtin() when we exit()
directly like this.

Each of these cases looks like a simple and obvious conversion, and I
certainly don't mind us doing it.

But I do wonder what SunCC is complaining about exactly. Calling exit()
means you don't have to worry about cleanup anymore. Does the compiler
not have any notion of NORETURN or equivalent? If so, I'd expect many
more complaints in general that we probably _won't_ want to silence,
because it will be awkward to do so.

It is curious that is only complaining abut exit() calls and not die(), 
maybe that is just a coincidence though if it is not complaining about 
all calls to exit()

Best Wishes

Phillip

quoted

diff --git a/builtin/difftool.c b/builtin/difftool.c
index 89334b77fb..6a9242a803 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c

@@ -675,7 +675,7 @@ static int run_file_diff(int prompt, const char *prefix,
  		"GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
  		NULL
  	};
-	int ret = 0, i;
+	int i;
  
  	if (prompt > 0)
  		env[2] = "GIT_DIFFTOOL_PROMPT=true";

@@ -686,8 +686,7 @@ static int run_file_diff(int prompt, const char *prefix,
  	strvec_push(&args, "diff");
  	for (i = 0; i < argc; i++)
  		strvec_push(&args, argv[i]);
-	ret = run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
-	exit(ret);
+	return run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
  }

This one I'm not surprised that a compiler would complain about. The
function returns an int, but there are no return paths from the
function (and hence the caller doing "return run_diff_files()" likewise
could not ever return there. Which is not quite what you said it
complained about above, hence my curiosity. :)

-Peff

On Thu, Jun 10 2021, Phillip Wood wrote:

On 08/06/2021 07:49, Jeff King wrote:

quoted

On Mon, Jun 07, 2021 at 01:12:48PM +0200, Ævar Arnfjörð Bjarmason wrote:

quoted

Change various cmd_* functions to use "return" instead of exit() to
indicate an exit code. On Solaris with SunCC the compiler legitimately
complains about these, since we'll e.g. skip the cleanup (e.g. closing
fd's, erroring if we can't) in git.c's run_builtin() when we exit()
directly like this.

Each of these cases looks like a simple and obvious conversion, and
I
certainly don't mind us doing it.
But I do wonder what SunCC is complaining about exactly. Calling
exit()
means you don't have to worry about cleanup anymore. Does the compiler
not have any notion of NORETURN or equivalent? If so, I'd expect many
more complaints in general that we probably _won't_ want to silence,
because it will be awkward to do so.

It is curious that is only complaining abut exit() calls and not
die(), maybe that is just a coincidence though if it is not
complaining about all calls to exit()

It's "function has no return statement", usually things that die() will
also return if nothing goes wrong.

It also complains about e.g. cram() in imap-send.c under NO_OPENSSL=Y,
which is an "non-void" returning function stub that just calls die().

I recall raising that on-list in the past and proposing that they have a
dummy return value, but that met lukewarm support, so I just consider
them false alarms and try to ignore them.

I do think we should have "die_report" or whatever versions of die() so you could do:

    return die_report(...);

You can do that with error(), but that means changing the error message
from "fatal:" to "error:". Those cases are obscure though, e.g. piping
to a full disk where we'd die for other reasons. Now we'll hide that
error.

I mean, we'd do so anyway since cmd_builtin() in git.c won't reach the
"closing fd's" check, but that could be fixed, and there's other similar
cases where we needlessly conflate the desire to say "fatal" and exit
with 128 with returning an error and doing cleanup etc.

quoted

quoted

diff --git a/builtin/difftool.c b/builtin/difftool.c
index 89334b77fb..6a9242a803 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c

@@ -675,7 +675,7 @@ static int run_file_diff(int prompt, const char *prefix,
  		"GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
  		NULL
  	};
-	int ret = 0, i;
+	int i;
    	if (prompt > 0)
  		env[2] = "GIT_DIFFTOOL_PROMPT=true";

@@ -686,8 +686,7 @@ static int run_file_diff(int prompt, const char *prefix,
  	strvec_push(&args, "diff");
  	for (i = 0; i < argc; i++)
  		strvec_push(&args, argv[i]);
-	ret = run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
-	exit(ret);
+	return run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
  }

This one I'm not surprised that a compiler would complain about. The
function returns an int, but there are no return paths from the
function (and hence the caller doing "return run_diff_files()" likewise
could not ever return there. Which is not quite what you said it
complained about above, hence my curiosity. :)
-Peff