builtin/diff-pairs: allow explicit diff queue flush
The diffs queued from git-diff-pairs(1) are flushed when stdin is closed. To enable greater flexibility, allow control over when the diff queue is flushed by writing a single NUL byte on stdin between input file pairs. Diff output between flushes is separated by a single NUL byte. Signed-off-by: Justin Tobler <jltobler@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Justin Tobler committed
Feb 28, 2025 at 15:33 UTC
cf15095ec52f1e997ec9eef42bdf275d2a68fe66
3 files changed
+27
Documentation/git-diff-pairs.adoc
+4
@@ -17,6 +17,10 @@ in the NUL-terminated raw output format as generated by commands such as `git
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diff-tree -z -r --raw`. By default, the outputted diffs are computed and shown
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in the patch format when stdin closes.
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+A single NUL byte may be written to stdin between raw input lines to compute
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+file pair diffs up to that point instead of waiting for stdin to close. A NUL
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+byte is also written to the output to delimit between these batches of diffs.
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+
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Usage of this command enables the traditional diff pipeline to be broken up
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into separate stages where `diff-pairs` acts as the output phase. Other
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commands, such as `diff-tree`, may serve as a frontend to compute the raw
builtin/diff-pairs.c
+14
@@ -57,6 +57,7 @@ int cmd_diff_pairs(int argc, const char **argv, const char *prefix,
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show_usage_with_options_if_asked(argc, argv, builtin_diff_pairs_usage, parseopts);
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repo_config(repo, git_diff_basic_config, NULL);
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+ revs.diffopt.no_free = 1;
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revs.disable_stdin = 1;
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revs.abbrev = 0;
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revs.diff = 1;
@@ -106,6 +107,18 @@ int cmd_diff_pairs(int argc, const char **argv, const char *prefix,
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break;
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p = meta.buf;
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+ if (!*p) {
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+ diffcore_std(&revs.diffopt);
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+ diff_flush(&revs.diffopt);
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+ /*
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+ * When the diff queue is explicitly flushed, append a
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+ * NUL byte to separate batches of diffs.
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+ */
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+ fputc('\0', revs.diffopt.file);
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+ fflush(revs.diffopt.file);
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+ continue;
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+ }
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+
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if (*p != ':')
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die(_("invalid raw diff input"));
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p++;
@@ -179,6 +192,7 @@ int cmd_diff_pairs(int argc, const char **argv, const char *prefix,
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}
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}
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+ revs.diffopt.no_free = 0;
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diffcore_std(&revs.diffopt);
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diff_flush(&revs.diffopt);
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ret = diff_result_code(&revs);
t/t4070-diff-pairs.sh
+9
@@ -78,4 +78,13 @@ test_expect_success 'diff-pairs does not support pathspec arguments' '
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test_cmp expect err
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'
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+test_expect_success 'diff-pairs explicit queue flush' '
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+ git diff-tree -r -M -C -C -z base new >expect &&
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+ printf "\0" >>expect &&
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+ git diff-tree -r -M -C -C -z base new >>expect &&
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+
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+ git diff-pairs --raw -z <expect >actual &&
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+ test_cmp expect actual
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+'
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+
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test_done