From: Paul Tarjan via GitGitGadget Date: Sat, 28 Feb 2026 17:37:57 GMT Subject: [PATCH v2] fsmonitor-watchman: fix variable reference and remove redundant code Message-ID: In-Reply-To: From: Paul Tarjan The is_work_tree_watched() function in fsmonitor-watchman.sample has two bugs: 1. Wrong variable in error check: After calling watchman_clock(), the result is stored in $o, but the code checks $output->{error} instead of $o->{error}. This means errors from the clock command are silently ignored. 2. Double output violates protocol: When the retry path triggers (the directory wasn't initially watched), output_result() is called with the "/" flag, then launch_watchman() is called recursively which calls output_result() again. This outputs two clock tokens to stdout, but git's fsmonitor v2 protocol expects exactly one response. Fix #1 by checking $o->{error} after watchman_clock(). Fix #2 by removing the recursive launch_watchman() call. The "/" "everything is dirty" flag already tells git to do a full scan, and git will call the hook again on the next invocation with a valid clock token. With the recursive call removed, the $retry guard is no longer needed since it only existed to prevent infinite recursion. Remove it. Apply the same fixes to the test helper scripts in t/t7519/. Signed-off-by: Paul Tarjan --- fsmonitor-watchman: fix variable reference and remove redundant code fsmonitor-watchman: fix variable reference and remove redundant code The is_work_tree_watched() function in fsmonitor-watchman.sample has two bugs: 1. Wrong variable in error check: After calling watchman_clock(), the result is stored in $o, but the code checks $output->{error} instead of $o->{error}. This means errors from the clock command are silently ignored. 2. Double output violates protocol: When the retry path triggers (the directory wasn't initially watched), output_result() is called with the "/" flag, then launch_watchman() is called recursively which calls output_result() again. This outputs two clock tokens to stdout, but git's fsmonitor v2 protocol expects exactly one response. Fix #1 by checking $o->{error} after watchman_clock(). Fix #2 by removing the recursive launch_watchman() call. The "/" "everything is dirty" flag already tells git to do a full scan, and git will call the hook again on the next invocation with a valid clock token. Apply the same fixes to the test helper scripts in t/t7519/. Changes since v1: * Removed $retry variable and associated logic, which only existed to prevent infinite recursion from the now-removed recursive launch_watchman() call * Fixed commit authorship Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-2180%2Fptarjan%2Fclaude%2Ffix-watchman-query-bug-sfbIw-v2 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-2180/ptarjan/claude/fix-watchman-query-bug-sfbIw-v2 Pull-Request: https://github.com/git/git/pull/2180 Range-diff vs v1: 1: 116d26287f ! 1: b9e00b8ab5 fsmonitor: fix two bugs in watchman hook retry path @@ ## Metadata ## -Author: Claude +Author: Paul Tarjan ## Commit message ## - fsmonitor: fix two bugs in watchman hook retry path + fsmonitor-watchman: fix variable reference and remove redundant code The is_work_tree_watched() function in fsmonitor-watchman.sample has two bugs: @@ Commit message git will call the hook again on the next invocation with a valid clock token. + With the recursive call removed, the $retry guard is no longer needed + since it only existed to prevent infinite recursion. Remove it. + Apply the same fixes to the test helper scripts in t/t7519/. Signed-off-by: Paul Tarjan ## t/t7519/fsmonitor-watchman ## +@@ t/t7519/fsmonitor-watchman: if ($^O =~ 'msys' || $^O =~ 'cygwin') { + $git_work_tree = Cwd::cwd(); + } + +-my $retry = 1; +- + launch_watchman(); + + sub launch_watchman { +@@ t/t7519/fsmonitor-watchman: sub launch_watchman { + + my $o = $json_pkg->new->utf8->decode($response); + +- if ($retry > 0 and $o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) { ++ if ($o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) { + print STDERR "Adding '$git_work_tree' to watchman's watch list.\n"; +- $retry--; + qx/watchman watch "$git_work_tree"/; + die "Failed to make watchman watch '$git_work_tree'.\n" . + "Falling back to scanning...\n" if $? != 0; @@ t/t7519/fsmonitor-watchman: sub launch_watchman { close $fh; @@ t/t7519/fsmonitor-watchman: sub launch_watchman { ## t/t7519/fsmonitor-watchman-v2 ## +@@ t/t7519/fsmonitor-watchman-v2: if ($version ne 2) { + + my $git_work_tree = get_working_dir(); + +-my $retry = 1; +- + my $json_pkg; + eval { + require JSON::XS; +@@ t/t7519/fsmonitor-watchman-v2: sub watchman_query { + sub is_work_tree_watched { + my ($output) = @_; + my $error = $output->{error}; +- if ($retry > 0 and $error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { +- $retry--; ++ if ($error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { + my $response = qx/watchman watch "$git_work_tree"/; + die "Failed to make watchman watch '$git_work_tree'.\n" . + "Falling back to scanning...\n" if $? != 0; @@ t/t7519/fsmonitor-watchman-v2: sub is_work_tree_watched { # Watchman query just to get it over with now so we won't pay # the cost in git to look up each individual file. @@ t/t7519/fsmonitor-watchman-v2: sub is_work_tree_watched { ## templates/hooks/fsmonitor-watchman.sample ## +@@ templates/hooks/fsmonitor-watchman.sample: if ($version ne 2) { + + my $git_work_tree = get_working_dir(); + +-my $retry = 1; +- + my $json_pkg; + eval { + require JSON::XS; +@@ templates/hooks/fsmonitor-watchman.sample: sub watchman_query { + sub is_work_tree_watched { + my ($output) = @_; + my $error = $output->{error}; +- if ($retry > 0 and $error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { +- $retry--; ++ if ($error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { + my $response = qx/watchman watch "$git_work_tree"/; + die "Failed to make watchman watch '$git_work_tree'.\n" . + "Falling back to scanning...\n" if $? != 0; @@ templates/hooks/fsmonitor-watchman.sample: sub is_work_tree_watched { # Watchman query just to get it over with now so we won't pay # the cost in git to look up each individual file. t/t7519/fsmonitor-watchman | 6 +----- t/t7519/fsmonitor-watchman-v2 | 10 ++-------- templates/hooks/fsmonitor-watchman.sample | 10 ++-------- 3 files changed, 5 insertions(+), 21 deletions(-) diff --git a/t/t7519/fsmonitor-watchman b/t/t7519/fsmonitor-watchman index 264b9daf83..bcc055c1e0 100755 --- a/t/t7519/fsmonitor-watchman +++ b/t/t7519/fsmonitor-watchman @@ -38,8 +38,6 @@ if ($^O =~ 'msys' || $^O =~ 'cygwin') { $git_work_tree = Cwd::cwd(); } -my $retry = 1; - launch_watchman(); sub launch_watchman { @@ -92,9 +90,8 @@ sub launch_watchman { my $o = $json_pkg->new->utf8->decode($response); - if ($retry > 0 and $o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) { + if ($o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) { print STDERR "Adding '$git_work_tree' to watchman's watch list.\n"; - $retry--; qx/watchman watch "$git_work_tree"/; die "Failed to make watchman watch '$git_work_tree'.\n" . "Falling back to scanning...\n" if $? != 0; @@ -109,7 +106,6 @@ sub launch_watchman { close $fh; print "/\0"; - eval { launch_watchman() }; exit 0; } diff --git a/t/t7519/fsmonitor-watchman-v2 b/t/t7519/fsmonitor-watchman-v2 index 14ed0aa42d..368604c278 100755 --- a/t/t7519/fsmonitor-watchman-v2 +++ b/t/t7519/fsmonitor-watchman-v2 @@ -29,8 +29,6 @@ if ($version ne 2) { my $git_work_tree = get_working_dir(); -my $retry = 1; - my $json_pkg; eval { require JSON::XS; @@ -122,8 +120,7 @@ sub watchman_query { sub is_work_tree_watched { my ($output) = @_; my $error = $output->{error}; - if ($retry > 0 and $error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { - $retry--; + if ($error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { my $response = qx/watchman watch "$git_work_tree"/; die "Failed to make watchman watch '$git_work_tree'.\n" . "Falling back to scanning...\n" if $? != 0; @@ -141,15 +138,12 @@ sub is_work_tree_watched { # Watchman query just to get it over with now so we won't pay # the cost in git to look up each individual file. my $o = watchman_clock(); - $error = $output->{error}; + $error = $o->{error}; die "Watchman: $error.\n" . "Falling back to scanning...\n" if $error; output_result($o->{clock}, ("/")); - $last_update_token = $o->{clock}; - - eval { launch_watchman() }; return 0; } diff --git a/templates/hooks/fsmonitor-watchman.sample b/templates/hooks/fsmonitor-watchman.sample index 23e856f5de..429e0a51c1 100755 --- a/templates/hooks/fsmonitor-watchman.sample +++ b/templates/hooks/fsmonitor-watchman.sample @@ -29,8 +29,6 @@ if ($version ne 2) { my $git_work_tree = get_working_dir(); -my $retry = 1; - my $json_pkg; eval { require JSON::XS; @@ -123,8 +121,7 @@ sub watchman_query { sub is_work_tree_watched { my ($output) = @_; my $error = $output->{error}; - if ($retry > 0 and $error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { - $retry--; + if ($error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { my $response = qx/watchman watch "$git_work_tree"/; die "Failed to make watchman watch '$git_work_tree'.\n" . "Falling back to scanning...\n" if $? != 0; @@ -142,15 +139,12 @@ sub is_work_tree_watched { # Watchman query just to get it over with now so we won't pay # the cost in git to look up each individual file. my $o = watchman_clock(); - $error = $output->{error}; + $error = $o->{error}; die "Watchman: $error.\n" . "Falling back to scanning...\n" if $error; output_result($o->{clock}, ("/")); - $last_update_token = $o->{clock}; - - eval { launch_watchman() }; return 0; } base-commit: 68cb7f9e92a5d8e9824f5b52ac3d0a9d8f653dbe -- gitgitgadget