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b5a8169752
Without this bug fix, t7519's four "status doesn't detect unreported modifications" test cases would fail occasionally (and, oddly enough, *a lot* more frequently on Windows). The reason is that these test cases intentionally use the side effect of `git status` to re-write the index if any updates were detected: they first clean the worktree, run `git status` to update the index as well as show the output to the casual reader, then make the worktree dirty again and expect no changes to reported if running with a mocked fsmonitor hook. The problem with this strategy was that the index was written during said `git status` on the clean worktree for the *wrong* reason: not because the index was marked as changed (it wasn't), but because the recorded mtimes were racy with the index' own mtime. As the mtime granularity on Windows is 100 nanoseconds (see e.g. https://docs.microsoft.com/en-us/windows/desktop/SysInfo/file-times), the mtimes of the files are often enough *not* racy with the index', so that that `git status` call currently does not always update the index (including the fsmonitor extension), causing the test case to fail. The obvious fix: if we change *any* index entry's `CE_FSMONITOR_VALID` flag, we should also mark the index as changed. That will cause the index to be written upon `git status`, *including* an updated fsmonitor extension. Side note: Even though the reader might think that the t7519 issue should be *much* more prevalent on Linux, given that the ext4 filesystem (that seems to be used by every Linux distribution) stores mtimes in nanosecond precision. However, ext4 uses `current_kernel_time()` (see https://unix.stackexchange.com/questions/11599#comment762968_11599; it is *amazingly* hard to find any proper source of information about such ext4 questions) whose accuracy seems to depend on many factors but is safely worse than the 100-nanosecond granularity of NTFS (again, it is *horribly* hard to find anything remotely authoritative about this question). So it seems that the racy index condition that hid the bug fixed by this patch simply is a lot more likely on Linux than on Windows. But not impossible ;-) Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
78 lines
2.4 KiB
C
78 lines
2.4 KiB
C
#ifndef FSMONITOR_H
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#define FSMONITOR_H
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#include "cache.h"
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#include "dir.h"
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extern struct trace_key trace_fsmonitor;
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/*
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* Read the fsmonitor index extension and (if configured) restore the
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* CE_FSMONITOR_VALID state.
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*/
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int read_fsmonitor_extension(struct index_state *istate, const void *data, unsigned long sz);
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/*
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* Fill the fsmonitor_dirty ewah bits with their state from the index,
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* before it is split during writing.
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*/
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void fill_fsmonitor_bitmap(struct index_state *istate);
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/*
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* Write the CE_FSMONITOR_VALID state into the fsmonitor index
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* extension. Reads from the fsmonitor_dirty ewah in the index.
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*/
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void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate);
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/*
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* Add/remove the fsmonitor index extension
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*/
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void add_fsmonitor(struct index_state *istate);
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void remove_fsmonitor(struct index_state *istate);
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/*
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* Add/remove the fsmonitor index extension as necessary based on the current
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* core.fsmonitor setting.
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*/
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void tweak_fsmonitor(struct index_state *istate);
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/*
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* Run the configured fsmonitor integration script and clear the
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* CE_FSMONITOR_VALID bit for any files returned as dirty. Also invalidate
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* any corresponding untracked cache directory structures. Optimized to only
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* run the first time it is called.
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*/
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void refresh_fsmonitor(struct index_state *istate);
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/*
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* Set the given cache entries CE_FSMONITOR_VALID bit. This should be
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* called any time the cache entry has been updated to reflect the
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* current state of the file on disk.
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*/
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static inline void mark_fsmonitor_valid(struct index_state *istate, struct cache_entry *ce)
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{
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if (core_fsmonitor && !(ce->ce_flags & CE_FSMONITOR_VALID)) {
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istate->cache_changed = 1;
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ce->ce_flags |= CE_FSMONITOR_VALID;
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trace_printf_key(&trace_fsmonitor, "mark_fsmonitor_clean '%s'", ce->name);
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}
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}
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/*
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* Clear the given cache entry's CE_FSMONITOR_VALID bit and invalidate
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* any corresponding untracked cache directory structures. This should
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* be called any time git creates or modifies a file that should
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* trigger an lstat() or invalidate the untracked cache for the
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* corresponding directory
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*/
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static inline void mark_fsmonitor_invalid(struct index_state *istate, struct cache_entry *ce)
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{
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if (core_fsmonitor) {
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ce->ce_flags &= ~CE_FSMONITOR_VALID;
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untracked_cache_invalidate_path(istate, ce->name, 1);
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trace_printf_key(&trace_fsmonitor, "mark_fsmonitor_invalid '%s'", ce->name);
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}
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}
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#endif
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