Message ID | pull.1497.v5.git.git.1687980390.gitgitgadget@gmail.com (mailing list archive) |
---|---|
Headers | show |
Series | config: remove global state from config iteration | expand |
"Glen Choo via GitGitGadget" <gitgitgadget@gmail.com> writes: > As promised, this version addresses the comments on v3. > > = Changes since v4 > > - Squash 6-7/12 since `test_must_fail` doesn't catch BUG() > - Move a hunk to later in the series where it belongs > - Replace a memcpy with `*a = *b` > > = Changes since v3 > > - Rebase onto newer 'master' > - Move the 'remove UNUSED from tr2_cfg_cb' hunk from 9/12 -> 8/12. It should > have been there all along; v3 8/12 didn't build at all. Looks like all my comments have been addressed, so this patch set looks good to me.
Jonathan Tan <jonathantanmy@google.com> writes: > "Glen Choo via GitGitGadget" <gitgitgadget@gmail.com> writes: >> As promised, this version addresses the comments on v3. >> >> = Changes since v4 >> >> - Squash 6-7/12 since `test_must_fail` doesn't catch BUG() >> - Move a hunk to later in the series where it belongs >> - Replace a memcpy with `*a = *b` >> >> = Changes since v3 >> >> - Rebase onto newer 'master' >> - Move the 'remove UNUSED from tr2_cfg_cb' hunk from 9/12 -> 8/12. It should >> have been there all along; v3 8/12 didn't build at all. > > Looks like all my comments have been addressed, so this patch set looks > good to me. Thanks. Queued.
Hi Glen Sorry it has taken me so long to look at these patches. I see they're in master now but I have just had a quick look through anyway and they looked good. It would definitely be nice to fix the hacky handling of "git checkout --conflict" at some point but that is a long standing problem and not the fault of this series. Best Wishes Phillip On 28/06/2023 20:26, Glen Choo via GitGitGadget wrote: > As promised, this version addresses the comments on v3. > > = Changes since v4 > > - Squash 6-7/12 since `test_must_fail` doesn't catch BUG() > - Move a hunk to later in the series where it belongs > - Replace a memcpy with `*a = *b` > > = Changes since v3 > > - Rebase onto newer 'master' > - Move the 'remove UNUSED from tr2_cfg_cb' hunk from 9/12 -> 8/12. It should > have been there all along; v3 8/12 didn't build at all. > > > Glen Choo (11): > config: inline git_color_default_config > urlmatch.h: use config_fn_t type > config: add ctx arg to config_fn_t > config.c: pass ctx in configsets > config: pass ctx with config files > config.c: pass ctx with CLI config > trace2: plumb config kvi > config: pass kvi to die_bad_number() > config.c: remove config_reader from configsets > config: add kvi.path, use it to evaluate includes > config: pass source to config_parser_event_fn_t > > alias.c | 3 +- > archive-tar.c | 5 +- > archive-zip.c | 1 + > builtin/add.c | 8 +- > builtin/blame.c | 5 +- > builtin/branch.c | 8 +- > builtin/cat-file.c | 5 +- > builtin/checkout.c | 12 +- > builtin/clean.c | 9 +- > builtin/clone.c | 11 +- > builtin/column.c | 3 +- > builtin/commit-graph.c | 3 +- > builtin/commit.c | 20 +- > builtin/config.c | 72 ++- > builtin/difftool.c | 5 +- > builtin/fetch.c | 13 +- > builtin/fsmonitor--daemon.c | 11 +- > builtin/grep.c | 12 +- > builtin/help.c | 5 +- > builtin/index-pack.c | 9 +- > builtin/log.c | 12 +- > builtin/merge.c | 7 +- > builtin/multi-pack-index.c | 1 + > builtin/pack-objects.c | 19 +- > builtin/patch-id.c | 5 +- > builtin/pull.c | 5 +- > builtin/push.c | 5 +- > builtin/read-tree.c | 5 +- > builtin/rebase.c | 5 +- > builtin/receive-pack.c | 15 +- > builtin/reflog.c | 7 +- > builtin/remote.c | 15 +- > builtin/repack.c | 5 +- > builtin/reset.c | 5 +- > builtin/send-pack.c | 5 +- > builtin/show-branch.c | 8 +- > builtin/stash.c | 5 +- > builtin/submodule--helper.c | 3 +- > builtin/tag.c | 9 +- > builtin/var.c | 5 +- > builtin/worktree.c | 5 +- > bundle-uri.c | 9 +- > color.c | 8 - > color.h | 6 +- > compat/mingw.c | 3 +- > compat/mingw.h | 4 +- > config.c | 552 +++++++----------- > config.h | 80 ++- > connect.c | 4 +- > .../coccinelle/config_fn_ctx.pending.cocci | 144 +++++ > contrib/coccinelle/git_config_number.cocci | 27 + > convert.c | 4 +- > credential.c | 1 + > delta-islands.c | 4 +- > diff.c | 19 +- > diff.h | 7 +- > fetch-pack.c | 5 +- > fmt-merge-msg.c | 7 +- > fmt-merge-msg.h | 3 +- > fsck.c | 12 +- > fsck.h | 4 +- > git-compat-util.h | 2 + > gpg-interface.c | 7 +- > grep.c | 7 +- > grep.h | 4 +- > help.c | 9 +- > http.c | 15 +- > ident.c | 4 +- > ident.h | 4 +- > imap-send.c | 7 +- > ll-merge.c | 1 + > ls-refs.c | 1 + > mailinfo.c | 5 +- > notes-utils.c | 4 +- > notes.c | 4 +- > pager.c | 5 +- > pretty.c | 1 + > promisor-remote.c | 4 +- > remote.c | 8 +- > revision.c | 4 +- > scalar.c | 4 +- > sequencer.c | 29 +- > setup.c | 18 +- > submodule-config.c | 31 +- > submodule-config.h | 3 +- > t/helper/test-config.c | 24 +- > t/helper/test-userdiff.c | 4 +- > t/t1300-config.sh | 27 + > trace2.c | 4 +- > trace2.h | 3 +- > trace2/tr2_cfg.c | 16 +- > trace2/tr2_sysenv.c | 3 +- > trace2/tr2_tgt.h | 4 +- > trace2/tr2_tgt_event.c | 4 +- > trace2/tr2_tgt_normal.c | 4 +- > trace2/tr2_tgt_perf.c | 4 +- > trailer.c | 2 + > upload-pack.c | 18 +- > urlmatch.c | 7 +- > urlmatch.h | 8 +- > worktree.c | 2 +- > xdiff-interface.c | 5 +- > xdiff-interface.h | 4 +- > 103 files changed, 960 insertions(+), 638 deletions(-) > create mode 100644 contrib/coccinelle/config_fn_ctx.pending.cocci > create mode 100644 contrib/coccinelle/git_config_number.cocci > > > base-commit: 6ff334181cfb6485d3ba50843038209a2a253907 > Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1497%2Fchooglen%2Fconfig%2Fno-global-v5 > Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1497/chooglen/config/no-global-v5 > Pull-Request: https://github.com/git/git/pull/1497 > > Range-diff vs v4: > > 1: 7bfffb454c5 = 1: 7bfffb454c5 config: inline git_color_default_config > 2: 739c519ce62 = 2: 739c519ce62 urlmatch.h: use config_fn_t type > 3: a9a0a50f32a = 3: a9a0a50f32a config: add ctx arg to config_fn_t > 4: 39b2e291f86 = 4: 39b2e291f86 config.c: pass ctx in configsets > 5: bfc6d2833c5 = 5: bfc6d2833c5 config: pass ctx with config files > 6: 897bdc759b5 < -: ----------- builtin/config.c: test misuse of format_config() > 7: 33e4437737d ! 6: 7b24eefbcf3 config.c: pass ctx with CLI config > @@ Commit message > * git_config_parse_parameter() hasn't been setting config source > information, so plumb "kvi" there too. > > - * "git config --get-urlmatch --show-scope" iterates config to collect > - values, but then attempts to display the scope after config iteration. > - Fix this by copying the "kvi" value in the collection phase so that it > - can be read back later. This means that we can now support "git config > - --get-urlmatch --show-origin" (we don't allow this combination of args > - because of this bug), but that is left unchanged for now. > + * Several sites in builtin/config.c have been calling current_config_*() > + functions outside of config callbacks (indirectly, via the > + format_config() helper), which means they're reading state that isn't > + set correctly: > > - * "git config --default" doesn't have config source metadata when > - displaying the default value. Fix this by treating the default value > - as if it came from the command line (e.g. like we do with "git -c" or > - "git config --file"), using kvi_from_param(). > + * "git config --get-urlmatch --show-scope" iterates config to collect > + values, but then attempts to display the scope after config > + iteration, causing the "unknown" scope to be shown instead of the > + config file's scope. It's clear that this wasn't intended: we knew > + that "--get-urlmatch" couldn't show config source metadata, which is > + why "--show-origin" was marked incompatible with "--get-urlmatch" > + when it was introduced [1]. It was most likely a mistake that we > + allowed "--show-scope" to sneak through. > + > + Fix this by copying the "kvi" value in the collection phase so that > + it can be read back later. This means that we can now support "git > + config --get-urlmatch --show-origin", but that is left unchanged > + for now. > + > + * "git config --default" doesn't have config source metadata when > + displaying the default value, so "--show-scope" also results in > + "unknown", and "--show-origin" results in a BUG(). Fix this by > + treating the default value as if it came from the command line (e.g. > + like we do with "git -c" or "git config --file"), using > + kvi_from_param(). > + > + [1] https://lore.kernel.org/git/20160205112001.GA13397@sigill.intra.peff.net/ > > Signed-off-by: Glen Choo <chooglen@google.com> > > @@ config.c: static int configset_find_element(struct config_set *set, const char * > const char *value) > { > @@ config.c: static int configset_add_value(struct config_reader *reader, > - l_item->e = e; > - l_item->value_index = e->value_list.nr - 1; > - > -- if (!reader->source) > -- BUG("configset_add_value has no source"); > + if (!reader->source) > + BUG("configset_add_value has no source"); > if (reader->source->name) { > - kvi_from_source(reader->source, current_config_scope(), kv_info); > + kvi_from_source(reader->source, kvi_p->scope, kv_info); > @@ config.h: void git_global_config(char **user, char **xdg); > * Match and parse a config key of the form: > > ## t/t1300-config.sh ## > -@@ t/t1300-config.sh: test_expect_success 'urlmatch with --show-scope' ' > - EOF > +@@ t/t1300-config.sh: test_expect_success 'urlmatch' ' > + test_cmp expect actual > + ' > > - cat >expect <<-EOF && > -- unknown http.cookiefile /tmp/cookie.txt > -- unknown http.sslverify false > ++test_expect_success 'urlmatch with --show-scope' ' > ++ cat >.git/config <<-\EOF && > ++ [http "https://weak.example.com"] > ++ sslVerify = false > ++ cookieFile = /tmp/cookie.txt > ++ EOF > ++ > ++ cat >expect <<-EOF && > + local http.cookiefile /tmp/cookie.txt > + local http.sslverify false > - EOF > - git config --get-urlmatch --show-scope HTTP https://weak.example.com >actual && > - test_cmp expect actual > ++ EOF > ++ git config --get-urlmatch --show-scope HTTP https://weak.example.com >actual && > ++ test_cmp expect actual > ++' > ++ > + test_expect_success 'urlmatch favors more specific URLs' ' > + cat >.git/config <<-\EOF && > + [http "https://example.com/"] > @@ t/t1300-config.sh: test_expect_success '--show-origin blob ref' ' > + test_cmp expect output > ' > > - test_expect_success '--show-origin with --default' ' > -- test_must_fail git config --show-origin --default foo some.key > ++test_expect_success '--show-origin with --default' ' > + git config --show-origin --default foo some.key >actual && > + echo "command line: foo" >expect && > + test_cmp expect actual > - ' > - > ++' > ++ > test_expect_success '--show-scope with --list' ' > + cat >expect <<-EOF && > + global user.global=true > @@ t/t1300-config.sh: test_expect_success '--show-scope with --show-origin' ' > - > - test_expect_success '--show-scope with --default' ' > - git config --show-scope --default foo some.key >actual && > -- echo "unknown foo" >expect && > -+ echo "command foo" >expect && > - test_cmp expect actual > + test_cmp expect output > ' > > ++test_expect_success '--show-scope with --default' ' > ++ git config --show-scope --default foo some.key >actual && > ++ echo "command foo" >expect && > ++ test_cmp expect actual > ++' > ++ > + test_expect_success 'override global and system config' ' > + test_when_finished rm -f \"\$HOME\"/.gitconfig && > + cat >"$HOME"/.gitconfig <<-EOF && > 8: 9bd5f60282c = 7: 7d64dcbdade trace2: plumb config kvi > 9: 114723ee4a7 = 8: 9e71c10ca0a config: pass kvi to die_bad_number() > 10: 807057b6d7f ! 9: 4776600e790 config.c: remove config_reader from configsets > @@ config.c: static int configset_add_value(const struct key_value_info *kvi_p, > l_item->e = e; > l_item->value_index = e->value_list.nr - 1; > > +- if (!reader->source) > +- BUG("configset_add_value has no source"); > - if (reader->source->name) { > - kvi_from_source(reader->source, kvi_p->scope, kv_info); > - } else { > - kvi_from_param(kv_info); > - } > -+ memcpy(kv_info, kvi_p, sizeof(struct key_value_info)); > ++ *kv_info = *kvi_p; > si->util = kv_info; > > return 0; > 11: 3f0f84df972 = 10: 2b33977aba6 config: add kvi.path, use it to evaluate includes > 12: fe2f154fe8b = 11: 8347d3c9b80 config: pass source to config_parser_event_fn_t >
As promised, this version addresses the comments on v3. = Changes since v4 - Squash 6-7/12 since `test_must_fail` doesn't catch BUG() - Move a hunk to later in the series where it belongs - Replace a memcpy with `*a = *b` = Changes since v3 - Rebase onto newer 'master' - Move the 'remove UNUSED from tr2_cfg_cb' hunk from 9/12 -> 8/12. It should have been there all along; v3 8/12 didn't build at all. Glen Choo (11): config: inline git_color_default_config urlmatch.h: use config_fn_t type config: add ctx arg to config_fn_t config.c: pass ctx in configsets config: pass ctx with config files config.c: pass ctx with CLI config trace2: plumb config kvi config: pass kvi to die_bad_number() config.c: remove config_reader from configsets config: add kvi.path, use it to evaluate includes config: pass source to config_parser_event_fn_t alias.c | 3 +- archive-tar.c | 5 +- archive-zip.c | 1 + builtin/add.c | 8 +- builtin/blame.c | 5 +- builtin/branch.c | 8 +- builtin/cat-file.c | 5 +- builtin/checkout.c | 12 +- builtin/clean.c | 9 +- builtin/clone.c | 11 +- builtin/column.c | 3 +- builtin/commit-graph.c | 3 +- builtin/commit.c | 20 +- builtin/config.c | 72 ++- builtin/difftool.c | 5 +- builtin/fetch.c | 13 +- builtin/fsmonitor--daemon.c | 11 +- builtin/grep.c | 12 +- builtin/help.c | 5 +- builtin/index-pack.c | 9 +- builtin/log.c | 12 +- builtin/merge.c | 7 +- builtin/multi-pack-index.c | 1 + builtin/pack-objects.c | 19 +- builtin/patch-id.c | 5 +- builtin/pull.c | 5 +- builtin/push.c | 5 +- builtin/read-tree.c | 5 +- builtin/rebase.c | 5 +- builtin/receive-pack.c | 15 +- builtin/reflog.c | 7 +- builtin/remote.c | 15 +- builtin/repack.c | 5 +- builtin/reset.c | 5 +- builtin/send-pack.c | 5 +- builtin/show-branch.c | 8 +- builtin/stash.c | 5 +- builtin/submodule--helper.c | 3 +- builtin/tag.c | 9 +- builtin/var.c | 5 +- builtin/worktree.c | 5 +- bundle-uri.c | 9 +- color.c | 8 - color.h | 6 +- compat/mingw.c | 3 +- compat/mingw.h | 4 +- config.c | 552 +++++++----------- config.h | 80 ++- connect.c | 4 +- .../coccinelle/config_fn_ctx.pending.cocci | 144 +++++ contrib/coccinelle/git_config_number.cocci | 27 + convert.c | 4 +- credential.c | 1 + delta-islands.c | 4 +- diff.c | 19 +- diff.h | 7 +- fetch-pack.c | 5 +- fmt-merge-msg.c | 7 +- fmt-merge-msg.h | 3 +- fsck.c | 12 +- fsck.h | 4 +- git-compat-util.h | 2 + gpg-interface.c | 7 +- grep.c | 7 +- grep.h | 4 +- help.c | 9 +- http.c | 15 +- ident.c | 4 +- ident.h | 4 +- imap-send.c | 7 +- ll-merge.c | 1 + ls-refs.c | 1 + mailinfo.c | 5 +- notes-utils.c | 4 +- notes.c | 4 +- pager.c | 5 +- pretty.c | 1 + promisor-remote.c | 4 +- remote.c | 8 +- revision.c | 4 +- scalar.c | 4 +- sequencer.c | 29 +- setup.c | 18 +- submodule-config.c | 31 +- submodule-config.h | 3 +- t/helper/test-config.c | 24 +- t/helper/test-userdiff.c | 4 +- t/t1300-config.sh | 27 + trace2.c | 4 +- trace2.h | 3 +- trace2/tr2_cfg.c | 16 +- trace2/tr2_sysenv.c | 3 +- trace2/tr2_tgt.h | 4 +- trace2/tr2_tgt_event.c | 4 +- trace2/tr2_tgt_normal.c | 4 +- trace2/tr2_tgt_perf.c | 4 +- trailer.c | 2 + upload-pack.c | 18 +- urlmatch.c | 7 +- urlmatch.h | 8 +- worktree.c | 2 +- xdiff-interface.c | 5 +- xdiff-interface.h | 4 +- 103 files changed, 960 insertions(+), 638 deletions(-) create mode 100644 contrib/coccinelle/config_fn_ctx.pending.cocci create mode 100644 contrib/coccinelle/git_config_number.cocci base-commit: 6ff334181cfb6485d3ba50843038209a2a253907 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1497%2Fchooglen%2Fconfig%2Fno-global-v5 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1497/chooglen/config/no-global-v5 Pull-Request: https://github.com/git/git/pull/1497 Range-diff vs v4: 1: 7bfffb454c5 = 1: 7bfffb454c5 config: inline git_color_default_config 2: 739c519ce62 = 2: 739c519ce62 urlmatch.h: use config_fn_t type 3: a9a0a50f32a = 3: a9a0a50f32a config: add ctx arg to config_fn_t 4: 39b2e291f86 = 4: 39b2e291f86 config.c: pass ctx in configsets 5: bfc6d2833c5 = 5: bfc6d2833c5 config: pass ctx with config files 6: 897bdc759b5 < -: ----------- builtin/config.c: test misuse of format_config() 7: 33e4437737d ! 6: 7b24eefbcf3 config.c: pass ctx with CLI config @@ Commit message * git_config_parse_parameter() hasn't been setting config source information, so plumb "kvi" there too. - * "git config --get-urlmatch --show-scope" iterates config to collect - values, but then attempts to display the scope after config iteration. - Fix this by copying the "kvi" value in the collection phase so that it - can be read back later. This means that we can now support "git config - --get-urlmatch --show-origin" (we don't allow this combination of args - because of this bug), but that is left unchanged for now. + * Several sites in builtin/config.c have been calling current_config_*() + functions outside of config callbacks (indirectly, via the + format_config() helper), which means they're reading state that isn't + set correctly: - * "git config --default" doesn't have config source metadata when - displaying the default value. Fix this by treating the default value - as if it came from the command line (e.g. like we do with "git -c" or - "git config --file"), using kvi_from_param(). + * "git config --get-urlmatch --show-scope" iterates config to collect + values, but then attempts to display the scope after config + iteration, causing the "unknown" scope to be shown instead of the + config file's scope. It's clear that this wasn't intended: we knew + that "--get-urlmatch" couldn't show config source metadata, which is + why "--show-origin" was marked incompatible with "--get-urlmatch" + when it was introduced [1]. It was most likely a mistake that we + allowed "--show-scope" to sneak through. + + Fix this by copying the "kvi" value in the collection phase so that + it can be read back later. This means that we can now support "git + config --get-urlmatch --show-origin", but that is left unchanged + for now. + + * "git config --default" doesn't have config source metadata when + displaying the default value, so "--show-scope" also results in + "unknown", and "--show-origin" results in a BUG(). Fix this by + treating the default value as if it came from the command line (e.g. + like we do with "git -c" or "git config --file"), using + kvi_from_param(). + + [1] https://lore.kernel.org/git/20160205112001.GA13397@sigill.intra.peff.net/ Signed-off-by: Glen Choo <chooglen@google.com> @@ config.c: static int configset_find_element(struct config_set *set, const char * const char *value) { @@ config.c: static int configset_add_value(struct config_reader *reader, - l_item->e = e; - l_item->value_index = e->value_list.nr - 1; - -- if (!reader->source) -- BUG("configset_add_value has no source"); + if (!reader->source) + BUG("configset_add_value has no source"); if (reader->source->name) { - kvi_from_source(reader->source, current_config_scope(), kv_info); + kvi_from_source(reader->source, kvi_p->scope, kv_info); @@ config.h: void git_global_config(char **user, char **xdg); * Match and parse a config key of the form: ## t/t1300-config.sh ## -@@ t/t1300-config.sh: test_expect_success 'urlmatch with --show-scope' ' - EOF +@@ t/t1300-config.sh: test_expect_success 'urlmatch' ' + test_cmp expect actual + ' - cat >expect <<-EOF && -- unknown http.cookiefile /tmp/cookie.txt -- unknown http.sslverify false ++test_expect_success 'urlmatch with --show-scope' ' ++ cat >.git/config <<-\EOF && ++ [http "https://weak.example.com"] ++ sslVerify = false ++ cookieFile = /tmp/cookie.txt ++ EOF ++ ++ cat >expect <<-EOF && + local http.cookiefile /tmp/cookie.txt + local http.sslverify false - EOF - git config --get-urlmatch --show-scope HTTP https://weak.example.com >actual && - test_cmp expect actual ++ EOF ++ git config --get-urlmatch --show-scope HTTP https://weak.example.com >actual && ++ test_cmp expect actual ++' ++ + test_expect_success 'urlmatch favors more specific URLs' ' + cat >.git/config <<-\EOF && + [http "https://example.com/"] @@ t/t1300-config.sh: test_expect_success '--show-origin blob ref' ' + test_cmp expect output ' - test_expect_success '--show-origin with --default' ' -- test_must_fail git config --show-origin --default foo some.key ++test_expect_success '--show-origin with --default' ' + git config --show-origin --default foo some.key >actual && + echo "command line: foo" >expect && + test_cmp expect actual - ' - ++' ++ test_expect_success '--show-scope with --list' ' + cat >expect <<-EOF && + global user.global=true @@ t/t1300-config.sh: test_expect_success '--show-scope with --show-origin' ' - - test_expect_success '--show-scope with --default' ' - git config --show-scope --default foo some.key >actual && -- echo "unknown foo" >expect && -+ echo "command foo" >expect && - test_cmp expect actual + test_cmp expect output ' ++test_expect_success '--show-scope with --default' ' ++ git config --show-scope --default foo some.key >actual && ++ echo "command foo" >expect && ++ test_cmp expect actual ++' ++ + test_expect_success 'override global and system config' ' + test_when_finished rm -f \"\$HOME\"/.gitconfig && + cat >"$HOME"/.gitconfig <<-EOF && 8: 9bd5f60282c = 7: 7d64dcbdade trace2: plumb config kvi 9: 114723ee4a7 = 8: 9e71c10ca0a config: pass kvi to die_bad_number() 10: 807057b6d7f ! 9: 4776600e790 config.c: remove config_reader from configsets @@ config.c: static int configset_add_value(const struct key_value_info *kvi_p, l_item->e = e; l_item->value_index = e->value_list.nr - 1; +- if (!reader->source) +- BUG("configset_add_value has no source"); - if (reader->source->name) { - kvi_from_source(reader->source, kvi_p->scope, kv_info); - } else { - kvi_from_param(kv_info); - } -+ memcpy(kv_info, kvi_p, sizeof(struct key_value_info)); ++ *kv_info = *kvi_p; si->util = kv_info; return 0; 11: 3f0f84df972 = 10: 2b33977aba6 config: add kvi.path, use it to evaluate includes 12: fe2f154fe8b = 11: 8347d3c9b80 config: pass source to config_parser_event_fn_t