Rename FISH_READ_BYTE_LIMIT to fish_read_limit

Fixes #4414

doc_src/index.hdr.in

@@ -475,7 +475,7 @@ The exit status of the last run command substitution is available in the <a href
 
 Only part of the output can be used, see <a href='#expand-index-range'>index range expansion</a> for details.
 
-Fish has a default limit of 10 MiB on the amount of data a command substitution can output. If the limit is exceeded the entire command, not just the substitution, is failed and `$status` is set to 122. You can modify the limit by setting the `FISH_READ_BYTE_LIMIT` variable at any time including in the environment before fish starts running. If you set it to zero then no limit is imposed. This is a safety mechanism to keep the shell from consuming an too much memory if a command outputs an unreasonable amount of data. Note that this limit also affects how much data the `read` command will process.
+Fish has a default limit of 10 MiB on the amount of data a command substitution can output. If the limit is exceeded the entire command, not just the substitution, is failed and `$status` is set to 122. You can modify the limit by setting the `fish_read_limit` variable at any time including in the environment before fish starts running. If you set it to zero then no limit is imposed. This is a safety mechanism to keep the shell from consuming an too much memory if a command outputs an unreasonable amount of data. Note that this limit also affects how much data the `read` command will process.
 
 Examples:
 

doc_src/read.txt

@@ -61,7 +61,7 @@ Otherwise, it is set to 0.
 In order to protect the shell from consuming too many system resources, `read` will only consume a
 maximum of 10 MiB (1048576 bytes); if the terminator is not reached before this limit then VARIABLE
 is set to empty and the exit status is set to 122. This limit can be altered with the
-`FISH_READ_BYTE_LIMIT` variable. If set to 0 (zero), the limit is removed.
+`fish_read_limit` variable. If set to 0 (zero), the limit is removed.
 
 \subsection read-history Using another read history file
 

src/env.cpp

@@ -69,7 +69,7 @@
 extern char **environ;
 
 // Limit `read` to 10 MiB (bytes not wide chars) by default. This can be overridden by the
-// FISH_READ_BYTE_LIMIT variable.
+// fish_read_limit variable.
 #define READ_BYTE_LIMIT 10 * 1024 * 1024
 size_t read_byte_limit = READ_BYTE_LIMIT;
 
@@ -680,11 +680,11 @@ bool env_set_pwd() {
 /// Allow the user to override the limit on how much data the `read` command will process.
 /// This is primarily for testing but could be used by users in special situations.
 void env_set_read_limit() {
-    auto read_byte_limit_var = env_get(L"FISH_READ_BYTE_LIMIT");
+    auto read_byte_limit_var = env_get(L"fish_read_limit");
     if (!read_byte_limit_var.missing_or_empty()) {
         size_t limit = fish_wcstoull(read_byte_limit_var->as_string().c_str());
         if (errno) {
-            debug(1, "Ignoring FISH_READ_BYTE_LIMIT since it is not valid");
+            debug(1, "Ignoring fish_read_limit since it is not valid");
         } else {
             read_byte_limit = limit;
         }
@@ -846,7 +846,7 @@ static void setup_var_dispatch_table() {
     var_dispatch_table.emplace(L"fish_escape_delay_ms", handle_escape_delay_change);
     var_dispatch_table.emplace(L"LINES", handle_term_size_change);
     var_dispatch_table.emplace(L"COLUMNS", handle_term_size_change);
-    var_dispatch_table.emplace(L"FISH_READ_BYTE_LIMIT", handle_read_limit_change);
+    var_dispatch_table.emplace(L"fish_read_limit", handle_read_limit_change);
     var_dispatch_table.emplace(L"fish_history", handle_fish_history_change);
     var_dispatch_table.emplace(L"TZ", handle_tz_change);
 }

tests/read.in

@@ -135,13 +135,13 @@ rm $path
 # The following tests verify that `read` correctly handles the limit on the
 # number of bytes consumed.
 #
-set FISH_READ_BYTE_LIMIT 8192
+set fish_read_limit 8192
 set line abcdefghijklmnopqrstuvwxyz
 
 # Ensure the `read` command terminates if asked to read too much data. The var
 # should be empty. We throw away any data we read if it exceeds the limit on
 # what we consider reasonable.
-yes $line | dd bs=1024 count=(math "1 + $FISH_READ_BYTE_LIMIT / 1024") ^/dev/null | read --null x
+yes $line | dd bs=1024 count=(math "1 + $fish_read_limit / 1024") ^/dev/null | read --null x
 if test $status -ne 122
     echo reading too much data did not terminate with failure status
 end
@@ -155,7 +155,7 @@ and echo reading too much data resulted in a var with unexpected data
 # Ensure the `read` command terminates if asked to read too much data even if
 # given an explicit limit. The var should be empty. We throw away any data we
 # read if it exceeds the limit on what we consider reasonable.
-yes $line | read --null --nchars=(math "$FISH_READ_BYTE_LIMIT + 1") x
+yes $line | read --null --nchars=(math "$fish_read_limit + 1") x
 if test $status -ne 122
     echo reading too much data did not terminate with failure status
 end
@@ -178,21 +178,21 @@ if test $exp_length -ne $act_length
 end
 
 # Confirm we can read exactly up to the limit.
-yes $line | read --null --nchars $FISH_READ_BYTE_LIMIT x
+yes $line | read --null --nchars $fish_read_limit x
 if test $status -ne 0
     echo the read of the max amount of data with --nchars failed unexpectedly
 end
-if test (string length "$x") -ne $FISH_READ_BYTE_LIMIT
+if test (string length "$x") -ne $fish_read_limit
     echo reading the max amount of data with --nchars failed the length test
 end
 
 # Same as previous test but limit the amount of data fed to `read` rather than
 # using the `--nchars` flag.
-yes $line | dd bs=1024 count=(math "$FISH_READ_BYTE_LIMIT / 1024") ^/dev/null | read --null x
+yes $line | dd bs=1024 count=(math "$fish_read_limit / 1024") ^/dev/null | read --null x
 if test $status -ne 0
     echo the read of the max amount of data failed unexpectedly
 end
-if test (string length "$x") -ne $FISH_READ_BYTE_LIMIT
+if test (string length "$x") -ne $fish_read_limit
     echo reading the max amount of data with --nchars failed the length test
 end
 

tests/test_cmdsub.in

@@ -1,7 +1,7 @@
 # This tests various corner cases involving command substitution. Most
 # importantly the limits on the amount of data we'll substitute.
 
-set FISH_READ_BYTE_LIMIT 512
+set fish_read_limit 512
 
 function subme
     set -l x (string repeat -n $argv x)