From 33be6cf51acf74e623fb3c4e287f7aebbedf5c09 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ren=C3=A9=20Scharfe?= Date: Sun, 9 Jun 2024 09:38:24 +0200 Subject: [PATCH 1/3] t4020: test exit code with external diffs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add tests to check the exit code of git diff with its options --quiet and --exit-code when using an external diff program. Currently we cannot tell whether it found significant changes or not. While at it, document briefly that --quiet turns off execution of external diff programs because that behavior surprised me for a moment while writing the tests. Signed-off-by: René Scharfe Signed-off-by: Junio C Hamano --- Documentation/diff-options.txt | 1 + t/t4020-diff-external.sh | 53 ++++++++++++++++++++++++++++++++++ 2 files changed, 54 insertions(+) diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index c7df20e571..6b73daf540 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -820,6 +820,7 @@ ifndef::git-log[] --quiet:: Disable all output of the program. Implies `--exit-code`. + Disables execution of external diff helpers. endif::git-log[] endif::git-format-patch[] diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh index fdd865f7c3..4070523cdb 100755 --- a/t/t4020-diff-external.sh +++ b/t/t4020-diff-external.sh @@ -172,6 +172,59 @@ test_expect_success 'no diff with -diff' ' grep Binary out ' +check_external_diff () { + expect_code=$1 + expect_out=$2 + expect_err=$3 + command_code=$4 + shift 4 + options="$@" + + command="echo output; exit $command_code;" + desc="external diff '$command'" + with_options="${options:+ with }$options" + + test_expect_success "$desc via attribute$with_options" " + test_config diff.foo.command \"$command\" && + echo \"file diff=foo\" >.gitattributes && + test_expect_code $expect_code git diff $options >out 2>err && + test_cmp $expect_out out && + test_cmp $expect_err err + " + + test_expect_success "$desc via diff.external$with_options" " + test_config diff.external \"$command\" && + >.gitattributes && + test_expect_code $expect_code git diff $options >out 2>err && + test_cmp $expect_out out && + test_cmp $expect_err err + " + + test_expect_success "$desc via GIT_EXTERNAL_DIFF$with_options" " + >.gitattributes && + test_expect_code $expect_code env \ + GIT_EXTERNAL_DIFF=\"$command\" \ + git diff $options >out 2>err && + test_cmp $expect_out out && + test_cmp $expect_err err + " +} + +test_expect_success 'setup output files' ' + : >empty && + echo output >output && + echo "fatal: external diff died, stopping at file" >error +' + +check_external_diff 0 output empty 0 +check_external_diff 128 output error 1 + +check_external_diff 1 output empty 0 --exit-code +check_external_diff 128 output error 1 --exit-code + +check_external_diff 1 empty empty 0 --quiet +check_external_diff 1 empty empty 1 --quiet # we don't even call the program + echo NULZbetweenZwords | perl -pe 'y/Z/\000/' > file test_expect_success 'force diff with "diff"' ' From 54443bbfc38d0252b31c821fea77320fcf0fe277 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ren=C3=A9=20Scharfe?= Date: Sun, 9 Jun 2024 09:39:08 +0200 Subject: [PATCH 2/3] userdiff: add and use struct external_diff MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Wrap the string specifying the external diff command in a new struct to simplify adding attributes, which the next patch will do. Make sure external_diff() still returns NULL if neither the environment variable GIT_EXTERNAL_DIFF nor the configuration option diff.external is set, to continue allowing its use in a boolean context. Use a designated initializer for the default builtin userdiff driver to adjust to the type change of the second struct member. Spelling out only the non-zero members improves readability as a nice side-effect. No functional change intended. Signed-off-by: René Scharfe Signed-off-by: Junio C Hamano --- diff.c | 32 +++++++++++++++++--------------- userdiff.c | 4 ++-- userdiff.h | 6 +++++- 3 files changed, 24 insertions(+), 18 deletions(-) diff --git a/diff.c b/diff.c index e70301df76..4b86c61631 100644 --- a/diff.c +++ b/diff.c @@ -57,7 +57,7 @@ static int diff_color_moved_ws_default; static int diff_context_default = 3; static int diff_interhunk_context_default; static char *diff_word_regex_cfg; -static char *external_diff_cmd_cfg; +static struct external_diff external_diff_cfg; static char *diff_order_file_cfg; int diff_auto_refresh_index = 1; static int diff_mnemonic_prefix; @@ -431,7 +431,7 @@ int git_diff_ui_config(const char *var, const char *value, return 0; } if (!strcmp(var, "diff.external")) - return git_config_string(&external_diff_cmd_cfg, var, value); + return git_config_string(&external_diff_cfg.cmd, var, value); if (!strcmp(var, "diff.wordregex")) return git_config_string(&diff_word_regex_cfg, var, value); if (!strcmp(var, "diff.orderfile")) @@ -548,18 +548,20 @@ static char *quote_two(const char *one, const char *two) return strbuf_detach(&res, NULL); } -static const char *external_diff(void) +static const struct external_diff *external_diff(void) { - static const char *external_diff_cmd = NULL; + static struct external_diff external_diff_env, *external_diff_ptr; static int done_preparing = 0; if (done_preparing) - return external_diff_cmd; - external_diff_cmd = xstrdup_or_null(getenv("GIT_EXTERNAL_DIFF")); - if (!external_diff_cmd) - external_diff_cmd = external_diff_cmd_cfg; + return external_diff_ptr; + external_diff_env.cmd = xstrdup_or_null(getenv("GIT_EXTERNAL_DIFF")); + if (external_diff_env.cmd) + external_diff_ptr = &external_diff_env; + else if (external_diff_cfg.cmd) + external_diff_ptr = &external_diff_cfg; done_preparing = 1; - return external_diff_cmd; + return external_diff_ptr; } /* @@ -4375,7 +4377,7 @@ static void add_external_diff_name(struct repository *r, * infile2 infile2-sha1 infile2-mode [ rename-to ] * */ -static void run_external_diff(const char *pgm, +static void run_external_diff(const struct external_diff *pgm, const char *name, const char *other, struct diff_filespec *one, @@ -4386,7 +4388,7 @@ static void run_external_diff(const char *pgm, struct child_process cmd = CHILD_PROCESS_INIT; struct diff_queue_struct *q = &diff_queued_diff; - strvec_push(&cmd.args, pgm); + strvec_push(&cmd.args, pgm->cmd); strvec_push(&cmd.args, name); if (one && two) { @@ -4512,7 +4514,7 @@ static void fill_metainfo(struct strbuf *msg, } } -static void run_diff_cmd(const char *pgm, +static void run_diff_cmd(const struct external_diff *pgm, const char *name, const char *other, const char *attr_path, @@ -4530,8 +4532,8 @@ static void run_diff_cmd(const char *pgm, if (o->flags.allow_external || !o->ignore_driver_algorithm) drv = userdiff_find_by_path(o->repo->index, attr_path); - if (o->flags.allow_external && drv && drv->external) - pgm = drv->external; + if (o->flags.allow_external && drv && drv->external.cmd) + pgm = &drv->external; if (msg) { /* @@ -4597,7 +4599,7 @@ static void strip_prefix(int prefix_length, const char **namep, const char **oth static void run_diff(struct diff_filepair *p, struct diff_options *o) { - const char *pgm = external_diff(); + const struct external_diff *pgm = external_diff(); struct strbuf msg; struct diff_filespec *one = p->one; struct diff_filespec *two = p->two; diff --git a/userdiff.c b/userdiff.c index 82bc76b910..f47e2d9f36 100644 --- a/userdiff.c +++ b/userdiff.c @@ -333,7 +333,7 @@ PATTERNS("scheme", "|([^][)(}{[ \t])+"), PATTERNS("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$", "\\\\[a-zA-Z@]+|\\\\.|([a-zA-Z0-9]|[^\x01-\x7f])+"), -{ "default", NULL, NULL, -1, { NULL, 0 } }, +{ .name = "default", .binary = -1 }, }; #undef PATTERNS #undef IPATTERN @@ -445,7 +445,7 @@ int userdiff_config(const char *k, const char *v) if (!strcmp(type, "binary")) return parse_tristate(&drv->binary, k, v); if (!strcmp(type, "command")) - return git_config_string(&drv->external, k, v); + return git_config_string(&drv->external.cmd, k, v); if (!strcmp(type, "textconv")) return git_config_string(&drv->textconv, k, v); if (!strcmp(type, "cachetextconv")) diff --git a/userdiff.h b/userdiff.h index cc8e5abfef..2d59a8fc56 100644 --- a/userdiff.h +++ b/userdiff.h @@ -11,9 +11,13 @@ struct userdiff_funcname { int cflags; }; +struct external_diff { + char *cmd; +}; + struct userdiff_driver { const char *name; - char *external; + struct external_diff external; char *algorithm; int binary; struct userdiff_funcname funcname; From d7b97b7185521e3b9364b3abc6553df2480da173 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ren=C3=A9=20Scharfe?= Date: Sun, 9 Jun 2024 09:41:44 +0200 Subject: [PATCH 3/3] diff: let external diffs report that changes are uninteresting MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The options --exit-code and --quiet instruct git diff to indicate whether it found any significant changes by exiting with code 1 if it did and 0 if there were none. Currently this doesn't work if external diff programs are involved, as we have no way to learn what they found. Add that ability in the form of the new configuration options diff.trustExitCode and diff..trustExitCode and the environment variable GIT_EXTERNAL_DIFF_TRUST_EXIT_CODE. They pair with the config options diff.external and diff..command and the environment variable GIT_EXTERNAL_DIFF, respectively. The new options are off by default, keeping the old behavior. Enabling them indicates that the external diff returns exit code 1 if it finds significant changes and 0 if it doesn't, like diff(1). The name of the new options is taken from the git difftool and mergetool options of similar purpose. (There they enable passing on the exit code of a diff tool and to infer whether a merge done by a merge tool is successful.) The new feature sets the diff flag diff_from_contents in diff_setup_done() if we need the exit code and are allowed to call external diffs. This disables the optimization that avoids calling the program with --quiet. Add it back by skipping the call if the external diff is not able to report empty diffs. We can only do that check after evaluating the file-specific attributes in run_external_diff(). If we do run the external diff with --quiet, send its output to /dev/null. I considered checking the output of the external diff to check whether its empty. It was added as 11be65cfa4 (diff: fix --exit-code with external diff, 2024-05-05) and quickly reverted, as it does not work with external diffs that do not write to stdout. There's no reason why a graphical diff tool would even need to write anything there at all. I also considered using a non-zero exit code for empty diffs, which could be done without adding new configuration options. We'd need to disable the optimization that allows git diff --quiet to skip calling external diffs, though -- that might be quite surprising if graphical diff programs are involved. And assigning the opposite meaning of the exit codes compared to diff(1) and git diff --exit-code to the external diff can cause unnecessary confusion. Suggested-by: Phillip Wood Signed-off-by: René Scharfe Signed-off-by: Junio C Hamano --- Documentation/config/diff.txt | 18 +++++++++++++++++ Documentation/diff-options.txt | 6 +++++- Documentation/git.txt | 10 +++++++++ Documentation/gitattributes.txt | 5 +++++ diff.c | 36 ++++++++++++++++++++++++++++++++- t/t4020-diff-external.sh | 29 ++++++++++++++++++-------- userdiff.c | 4 ++++ userdiff.h | 1 + 8 files changed, 99 insertions(+), 10 deletions(-) diff --git a/Documentation/config/diff.txt b/Documentation/config/diff.txt index 5ce7b91f1d..190bda17e5 100644 --- a/Documentation/config/diff.txt +++ b/Documentation/config/diff.txt @@ -79,6 +79,15 @@ diff.external:: you want to use an external diff program only on a subset of your files, you might want to use linkgit:gitattributes[5] instead. +diff.trustExitCode:: + If this boolean value is set to true then the + `diff.external` command is expected to return exit code + 0 if it considers the input files to be equal or 1 if it + considers them to be different, like `diff(1)`. + If it is set to false, which is the default, then the command + is expected to return exit code 0 regardless of equality. + Any other exit code causes Git to report a fatal error. + diff.ignoreSubmodules:: Sets the default value of --ignore-submodules. Note that this affects only 'git diff' Porcelain, and not lower level 'diff' @@ -164,6 +173,15 @@ diff..command:: The custom diff driver command. See linkgit:gitattributes[5] for details. +diff..trustExitCode:: + If this boolean value is set to true then the + `diff..command` command is expected to return exit code + 0 if it considers the input files to be equal or 1 if it + considers them to be different, like `diff(1)`. + If it is set to false, which is the default, then the command + is expected to return exit code 0 regardless of equality. + Any other exit code causes Git to report a fatal error. + diff..xfuncname:: The regular expression that the diff driver should use to recognize the hunk header. A built-in pattern may also be used. diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index 6b73daf540..cd0b81adbb 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -820,7 +820,11 @@ ifndef::git-log[] --quiet:: Disable all output of the program. Implies `--exit-code`. - Disables execution of external diff helpers. + Disables execution of external diff helpers whose exit code + is not trusted, i.e. their respective configuration option + `diff.trustExitCode` or `diff..trustExitCode` or + environment variable `GIT_EXTERNAL_DIFF_TRUST_EXIT_CODE` is + false. endif::git-log[] endif::git-format-patch[] diff --git a/Documentation/git.txt b/Documentation/git.txt index a31a70acca..4489e2297a 100644 --- a/Documentation/git.txt +++ b/Documentation/git.txt @@ -644,6 +644,16 @@ parameter, . For each path `GIT_EXTERNAL_DIFF` is called, two environment variables, `GIT_DIFF_PATH_COUNTER` and `GIT_DIFF_PATH_TOTAL` are set. +`GIT_EXTERNAL_DIFF_TRUST_EXIT_CODE`:: + If this Boolean environment variable is set to true then the + `GIT_EXTERNAL_DIFF` command is expected to return exit code + 0 if it considers the input files to be equal or 1 if it + considers them to be different, like `diff(1)`. + If it is set to false, which is the default, then the command + is expected to return exit code 0 regardless of equality. + Any other exit code causes Git to report a fatal error. + + `GIT_DIFF_PATH_COUNTER`:: A 1-based counter incremented by one for every path. diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index 4338d023d9..80cae17f37 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -776,6 +776,11 @@ with the above configuration, i.e. `j-c-diff`, with 7 parameters, just like `GIT_EXTERNAL_DIFF` program is called. See linkgit:git[1] for details. +If the program is able to ignore certain changes (similar to +`git diff --ignore-space-change`), then also set the option +`trustExitCode` to true. It is then expected to return exit code 1 if +it finds significant changes and 0 if it doesn't. + Setting the internal diff algorithm ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/diff.c b/diff.c index 4b86c61631..39ba842049 100644 --- a/diff.c +++ b/diff.c @@ -432,6 +432,10 @@ int git_diff_ui_config(const char *var, const char *value, } if (!strcmp(var, "diff.external")) return git_config_string(&external_diff_cfg.cmd, var, value); + if (!strcmp(var, "diff.trustexitcode")) { + external_diff_cfg.trust_exit_code = git_config_bool(var, value); + return 0; + } if (!strcmp(var, "diff.wordregex")) return git_config_string(&diff_word_regex_cfg, var, value); if (!strcmp(var, "diff.orderfile")) @@ -556,6 +560,8 @@ static const struct external_diff *external_diff(void) if (done_preparing) return external_diff_ptr; external_diff_env.cmd = xstrdup_or_null(getenv("GIT_EXTERNAL_DIFF")); + if (git_env_bool("GIT_EXTERNAL_DIFF_TRUST_EXIT_CODE", 0)) + external_diff_env.trust_exit_code = 1; if (external_diff_env.cmd) external_diff_ptr = &external_diff_env; else if (external_diff_cfg.cmd) @@ -4387,6 +4393,19 @@ static void run_external_diff(const struct external_diff *pgm, { struct child_process cmd = CHILD_PROCESS_INIT; struct diff_queue_struct *q = &diff_queued_diff; + int quiet = !(o->output_format & DIFF_FORMAT_PATCH); + int rc; + + /* + * Trivial equality is handled by diff_unmodified_pair() before + * we get here. If we don't need to show the diff and the + * external diff program lacks the ability to tell us whether + * it's empty then we consider it non-empty without even asking. + */ + if (!pgm->trust_exit_code && quiet) { + o->found_changes = 1; + return; + } strvec_push(&cmd.args, pgm->cmd); strvec_push(&cmd.args, name); @@ -4408,7 +4427,15 @@ static void run_external_diff(const struct external_diff *pgm, diff_free_filespec_data(one); diff_free_filespec_data(two); cmd.use_shell = 1; - if (run_command(&cmd)) + cmd.no_stdout = quiet; + rc = run_command(&cmd); + if (!pgm->trust_exit_code && rc == 0) + o->found_changes = 1; + else if (pgm->trust_exit_code && rc == 0) + ; /* nothing */ + else if (pgm->trust_exit_code && rc == 1) + o->found_changes = 1; + else die(_("external diff died, stopping at %s"), name); remove_tempfile(); @@ -4926,6 +4953,13 @@ void diff_setup_done(struct diff_options *options) options->flags.exit_with_status = 1; } + /* + * External diffs could declare non-identical contents equal + * (think diff --ignore-space-change). + */ + if (options->flags.allow_external && options->flags.exit_with_status) + options->flags.diff_from_contents = 1; + options->diff_path_counter = 0; if (options->flags.follow_renames) diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh index 4070523cdb..3baa52a9bf 100755 --- a/t/t4020-diff-external.sh +++ b/t/t4020-diff-external.sh @@ -177,15 +177,17 @@ check_external_diff () { expect_out=$2 expect_err=$3 command_code=$4 - shift 4 + trust_exit_code=$5 + shift 5 options="$@" command="echo output; exit $command_code;" - desc="external diff '$command'" + desc="external diff '$command' with trustExitCode=$trust_exit_code" with_options="${options:+ with }$options" test_expect_success "$desc via attribute$with_options" " test_config diff.foo.command \"$command\" && + test_config diff.foo.trustExitCode $trust_exit_code && echo \"file diff=foo\" >.gitattributes && test_expect_code $expect_code git diff $options >out 2>err && test_cmp $expect_out out && @@ -194,6 +196,7 @@ check_external_diff () { test_expect_success "$desc via diff.external$with_options" " test_config diff.external \"$command\" && + test_config diff.trustExitCode $trust_exit_code && >.gitattributes && test_expect_code $expect_code git diff $options >out 2>err && test_cmp $expect_out out && @@ -204,6 +207,7 @@ check_external_diff () { >.gitattributes && test_expect_code $expect_code env \ GIT_EXTERNAL_DIFF=\"$command\" \ + GIT_EXTERNAL_DIFF_TRUST_EXIT_CODE=$trust_exit_code \ git diff $options >out 2>err && test_cmp $expect_out out && test_cmp $expect_err err @@ -216,14 +220,23 @@ test_expect_success 'setup output files' ' echo "fatal: external diff died, stopping at file" >error ' -check_external_diff 0 output empty 0 -check_external_diff 128 output error 1 +check_external_diff 0 output empty 0 off +check_external_diff 128 output error 1 off +check_external_diff 0 output empty 0 on +check_external_diff 0 output empty 1 on +check_external_diff 128 output error 2 on -check_external_diff 1 output empty 0 --exit-code -check_external_diff 128 output error 1 --exit-code +check_external_diff 1 output empty 0 off --exit-code +check_external_diff 128 output error 1 off --exit-code +check_external_diff 0 output empty 0 on --exit-code +check_external_diff 1 output empty 1 on --exit-code +check_external_diff 128 output error 2 on --exit-code -check_external_diff 1 empty empty 0 --quiet -check_external_diff 1 empty empty 1 --quiet # we don't even call the program +check_external_diff 1 empty empty 0 off --quiet +check_external_diff 1 empty empty 1 off --quiet # we don't even call the program +check_external_diff 0 empty empty 0 on --quiet +check_external_diff 1 empty empty 1 on --quiet +check_external_diff 128 empty error 2 on --quiet echo NULZbetweenZwords | perl -pe 'y/Z/\000/' > file diff --git a/userdiff.c b/userdiff.c index f47e2d9f36..6cdfb147c3 100644 --- a/userdiff.c +++ b/userdiff.c @@ -446,6 +446,10 @@ int userdiff_config(const char *k, const char *v) return parse_tristate(&drv->binary, k, v); if (!strcmp(type, "command")) return git_config_string(&drv->external.cmd, k, v); + if (!strcmp(type, "trustexitcode")) { + drv->external.trust_exit_code = git_config_bool(k, v); + return 0; + } if (!strcmp(type, "textconv")) return git_config_string(&drv->textconv, k, v); if (!strcmp(type, "cachetextconv")) diff --git a/userdiff.h b/userdiff.h index 2d59a8fc56..f5cb53d0d4 100644 --- a/userdiff.h +++ b/userdiff.h @@ -13,6 +13,7 @@ struct userdiff_funcname { struct external_diff { char *cmd; + unsigned trust_exit_code:1; }; struct userdiff_driver {